Monday, June 7, 2021

The Missionary and the Enchanted Princess, a Frog Story

(Yeah, I know this is an old bad joke, and I know you're not supposed to take jokes too far. But this is how I'd see this story playing out in this world, in this church:)

Elder Michelson squatted down by the concrete irrigation mizo between the road and the water-covered rice field, staring at the edge of the water.

Elder Shirōto stopped beside him. "What'ya lookin' at?"

"Just a cute little frog."

Elder Shirōto squatted down, too. "It's rainy season. Lots of cute little frogs in this field. Wait. That frog's not so little." He reached out to grab the frog, but it sprang out of reach, and plopped into the water. Inexplicably, it swam back to the edge a little farther away and climbed back out, to sit on the edge of the mizo surrounding the field, watching the two missionaries cautiously.

"Help me!" it croaked shrilly.

Elder Michelson started.

Elder Shirōto chuckled. "That's a high-pitched croak for such a big frog."

Elder Michelson glanced back at his companion. "That was not just a croak!" Turning to look at the frog again, he added, "She said, 'Help me!'"

Elder Shirōto stared at his companion, then broke into a loud guffaw. "Right." He controlled his laughter. "Now it's going to say, 'I'm a beautiful princess, kiss me.'"

The frog puffed out its pouch. "I am a princess," she said, with all the haughtiness she could muster. "Maybe I'm not so beautiful, but if you kiss me, you'll free me from this spell."

Elder Michelson's chin dropped to his chest as he stared at the frog.

Elder Shirōto started laughing again. "What'd she say now? 'Kiss me and you'll live forever?" He paused for effect, and then added, in mock seriousness, "You'll be a frog, but you'll live forever." He snickered, "You should see your face, Elder Mishi."

"I said nothing of the sort," the frog ribbited huffily. "That's not the kind of spell I'm under."

Elder Michelson looked back at his companion with amusement and then turned again to examine the frog. "She says she's not under that kind of spell."

"Okay, Elder Mishi. Maybe you're the senior companion and I'm the greenie, but I think we should call our district leader and ask to be sent somewhere there are people to teach. We've hailed at every house in this village three times this month, and the best we've got is doors slid shut in our faces. I think the stress is gettin' to you."

"What a rude little boy he is. Don't listen to him. I need your help," the frog ribbitted plaintively.

"I'll admit, the way it croaks is cute." Elder Shirōto snickered again.

"Yeah, cute." Elder Michelson stood up. "But we're missionaries, and we should be doing other things."

Elder Shirōto nodded his head. "Now you're making sense."

"Listen, I'm desperate."  The frog hopped closer. "And I am a princess. I can reward you well if you kiss me."

"Reward? I don't guess either of us needs a reward. And missionaries aren't supposed to mess with magic." Elder Michelson turned to walk away.

"My father is powerful wizard king."

Elder Michelson stopped and thought for a moment. "Not magic, not rewards, but, ..." Then he squatted back down, and reached out and picked up the frog, now quite docile in his hand. He put it in his jacket pocket.

"Hey! Wait." Her cry was muffled by the fabric.

"That frog has prejudices. She jumped away from me, but lets you put it in your pocket. And now I'm calling it 'she'."

"So? You don't seem to be able to hear her words."

The frog poked its head out of the pocket. "D&C 50," it said. "Maybe he's not listening to the same spirit."

"D&C 50? Elder Shiro, this frog also invokes scriptures."

"Well," Elder Shirōto snickered again, "I guess we can't baptize her if she's already a member. What are you planning to do with her? -- it, I mean."

"We can teach members practice lessons and have gospel discussions and do service projects with them." Elder Michelson stood up, gently pushing the frog back into his suit pocket, and started walking. "So let's walk around the farms looking for people to help or talk to." He started walking along the dote toward a field where a farmer was working.

"There's no need to take me any place special," the frog croaked from inside the pocket. "You can break the spell anywhere, and here is just fine. Please?"

"Now she's," Elder Shirōto stopped to correct himself again. "Uhm, it's getting excited." He followed his companion.

"Please! I'll give you anything you want! I can do anything you want! -- for a day."

"Okay, so she really wants you to kiss her." Elder Shirōto continued chuckling.

"I thought you couldn't hear her." Elder Michelson kept walking.

"I'm guessing what she's saying. Hey, if I'm not careful, you're going to have me believing she's really talking."

"Two days!" The frog struggled inside the pocket.

"But you can't kiss her because you're a missionary."


"Anything you want for a week!" The frog practically screamed.

"She says she'll do anything we want for a week."

"We can't take that bargain. Even if she weren't a member, we couldn't force her to be baptized. Not she. It. And frogs don't need baptism."

"I'm not a member. I left the Church." Now it was pleading. "But I'll be in the water forever if someone doesn't kiss me!"

"You left the Church?" Elder Michelson stopped again, clearly puzzled.

Elder Shirōto stopped just in time to avoid bumping into his companion. "Shouldn't you be keeping this frog at arm's length?" he suggested.

"Arm's length?" the frog croaked.

"I'm not touching her while she's in my pocket."

"You're rationalizing, Elder." Elder Shirōto's voice took on an accusatory tone.


The frog poked it's head out of the pocket. "Why won't you kiss me?"

Now Elder Shirōto shrugged. "Why not kiss it and show yourself it's just your imagination? Look, you have a naked frog in your pocket. Kissing a frog can't be breaking the rules much worse than carrying it around."

"Naked frog. That's ..."

"Wash your laundry, clean your apartment, cook your meals, anything you want for a whole month!" she exclaimed.

"A month? You'll do anything we want for a whole month?"

"Not we. Elder Michelson. It's just a frog and it can't talk. I think we really should call the district leader."

"A month is long enough to teach someone the discussions, wouldn't you say, Elder Shirōto?"

"That does it, Elder. That frog is possessed, and it's got you under a curse, too. I'm calling the district leader." Elder Shirōto took out his cell phone and started dialing.

"Discussions?" The frog was shocked. "You wouldn't force me listen to those again!"

"Well," Elder Michelson sighed, "I guess, since we can't force you to get baptized, we probably shouldn't try to force you to participate in lessons, either." He scratched his chin.

"Answer your phone, Sister Morinokami, my companion's going crazy!" (Okay, we can see that it is not quite the Church of this present world.)

"Moshi-moshi. Sister Morinokami here." Her face came up on the screen. "Elder Shirōto. I can see you are excited. What's the problem that your companion can't handle?"

"My companion thinks he has a talking frog in his pocket!"

"So he's talking to an imaginary frog?"

"No, the frog is real."

"Then the problem is that the frog can't talk?"

"Huh?" Elder Shirōto's mouth dropped open slightly.

Siter Morinokami sighed in turn. "Let me try talking to the poor thing."

"Here, Elder Michelson, she wants to talk to you."

Elder Michelson took the phone. "Uhm, ..."

"Not you Elder Michelson, the frog!"

Elder Shirōto tilted his head in disbelief as Elder Michelson moved the phone so the frog was within the camera's view field.

"I can talk, and Elder Shirōto or whatever his name is, can't understand me."

"Oh, I see. He can't understand you. Hello, Miss Frog. I am Sister Morinokami."

"My name is not Frog."

"Okay, Miss Not-frog."

The frog huffed. "Cindy."

"What can we do for you, Miss Cindy?"

"She wants someone to kiss her and turn her back into a princess," Elder Michelson explained.

"What's this about a talking frog?" The voice of Sister Morinokami's companion came through the phone speakers.

"Let me handle this, Sister Severus. Is what he says true, Miss Cindy?"

"Pretty much. One little kiss and I'll be free of this spell."

"Well, kissing a princess would be breaking the rules, but kissing a frog, I think that would be an act of service."

"But, ... but, ..." Elder Michelson stuttered in surprise and panic. "Uhh, what if she turns into a princess while I'm still kissing her?"

"Then you'll have to back away quickly. Would that work, Miss Cindy?"

"Yes!" the frog practically squealed in excitement. "Just a little kiss from a handsome prince and I'll be free of this spell!"

"But," Elder Michelson pointed out, "a princess, ... a princess is interesting, sure. But princesses aren't very useful. They mostly waste their time trying to look beautiful. A talking frog, though, that's really cool."

"Elder Michelson!" Sister Morinokami remonstrated "You're being selfish."

"People would listen to the lessons if we had a talking frog," he explained.

"Not if they can't understand her, and that's not teaching the gospel, anyway," Sister Morinokami chastised.

"I think," Sister Severus commented, still off-screen, "we'd better call the mission president."



The Missionary and the Enchanted Princess,

a Frog Story

Joel Matthew Rees, Amagasaki, Japan
Copyright Joel Matthew Rees, 2019 - 2021
  1. The Frog (this chapter)
  2. Missionaries and Magic



(First write here:

Tuesday, September 29, 2020

33209: Rocks -- An Evening Together

Chapter 14.2 Rocks -- Moving Ahead

Chapter 14.3: Rocks -- An Evening Together

"I'm glad they had the Micro Chroma kits so we can take them home." Pat was examining the kit she was carrying as we entered the front door.

"I don't know about you guys, but I'm watching Hello Dolly tonight." Denise looked up from where she was watching TV and grinned as we came in the front door. 

I went to the kitchenette and set the bags I was carrying down.

Pat looked from her kit to the TV with a perplexed frown.

"Joe?" Julia looked over at me with a question in her eyes.

I shook my head. "No complaints from me."

Julia happily sat herself on the couch beside Denise, and I sat on the floor in front of her, leaning back against the couch beside her knees. 

Denny carried a couple of flat boxes into the kitchenette muttering something amusingly inane about TV.

Pat sat beside Julia. George and Mike took the flat boxes they were carrying into the kitchenette and returned to sit on the floor in front of her, dividing their attention between the TV and their kits.

"Somebody help me with the pizza I brought home!" Denny called out.

"Pizza?" Denise looked up from the TV hopefully. "I thought I smelled pizza. You brought some home?"

I got back up and went into the kitchen area, and George and Mike followed.

"On the company tab. Leftover from recruitment party."

We quickly had plates out and filled, and we passed them back into the living room, then passed out cups and soft drink bottles and returned to sitting on the floor.

"Tell your boss I thank him," Denise said between bites. "Very considerate, and better than the fried chicken I thought you had forgotten."

Denny grinned and joined us, giving Denise's rounding abdomen a caress before he sat down in front of her on the floor. "Kids asleep?"

"I doubt it."

The older boy peeked in through the boys' room door. I motioned to him to join us, and he came in and sat beside me. Denny stood back up and brought the younger one in, letting him lie in his lap and go back to sleep.


"Money is like manure." Julia gave me a glance and look as quiet as her voice. Denny and Denise had invited us to join in their family prayers, and, that done, Julia and I had carried the boys back to their beds and were now returning to the living room.

"Horace. Prompted evidently by Dolly's late husband from the other side." I also spoke quietly. "Spread it around and make green things grow. Not a bad metaphor, in a country where the banknotes are green."

She gave that a quiet laugh. "I guess it's not quite the same metaphor if the paper money isn't green."

"Still a useful principle."

Mike and George looked into the boys' room behind us. 

"Tight squeeze with three of us," George muttered. He turned back to the living room. "In my economics class, the teacher compared money to air. Pointed out that it's a medium of communication and essential to society's functioning."

"Essential?" Pat raised an eyebrow.

"You need something that can be used to communicate about value," he replied. 

"And any medium for communicating value just ends up looking like money," I added for him. 


Pat asked, "Then how about blood as a metaphor, since it has to circulate, and it carries stuff with it?"

Mike suppressed a snort. "More like pus."

I glanced up at him. "Because it tends to accumulate most in the wounds of society."

He nodded. "Exactly."

"Pus?" Julia scrunched her face. "Yuck. I could hate you for that, Mike." She shook her head and chuckled.

He just grinned back.

George groaned, but Pat nodded her head appreciatively. 

"Are you guys sure you're not already all related to the Reeves clan?" Denise asked.



"Philosophizing when we should be getting ready hit the hay," I explained.

"All the Reeveses do it," she laughingly complained.

Denny and I chuckled, and Julia reached out to take my hand. I gave her a smile and hug in reply.



Mike's low voice from beside me broke into my pre-dream thoughts. 

George's breathing from the other side of him was deep and regular.


"Julia tell you about her and me?"


"I wish I'd known you in high school."


"I think I needed better role models."

"Heh. I was not much of a role model in high school. Two years as a missionary helped, but, ..." and I stopped, in the realization that what I was about to say might be rather painful to Mike.

"Then maybe it's just that you and Julia are a better match than I'd have been for her."

"Maybe." I guessed he'd understood -- from his point of view -- some, if not all, of what I hadn't said.

"Even if ...," he trailed off.

 I waited for him to finish.

"Even though I can't expect to win Julia back, I want to be your friend."

"I hope we can be friends. I think Julia has some unhealed wounds that could be healed if we could all be friends."

"I think we can. But that's what it is. What I want to learn from you. I want to be able to think like that."

"I think it has something to do with religion."

"I know."

I waited for him to say something more.

"Thanks for letting us come along."

"Thanks for coming."

Mike grunted an affirmative, and slowly his breathing became regular and deep.

I was reminded of listening to my missionary companions' breathing in the middle of the night. There's something companionable about sharing a room to sleep in.


In the morning, we met the others at the park and spent a half hour walking and wading in the water before heading out for breakfast and to the surplus store.

John was happy to have the group of students browsing his selection of surplus, and he was happy to talk with me about the controller circuit.  He was worried about Motorola wanting to prevent him from passing the diagram and code out with the drives he sold, but Denny and assured him Motorola had agreed to keep it openly usable. 

Denny had already put copyright notice, notice of intent to patent, with notice of license and disclaimer of liability on the diagrams he passed out among his friends, and John was leaving the notices intact on the copies he kept to pass out.

About lunchtime, we went back to the park and met the other group coming in. Motorola's recruiters found us there, bringing more pizza and the remainder of the Micro Chroma 68 kits. But they kept the recruitment activities short, to leave the second group as much time at the surplus store as possible.

Julia and I spent a couple of hours with Denny and his boss at Motorola, learning how to use the test equipment to go through the reject bin to fish out parts that were functional enough, even though the batch they had come from had not qualified as product. We were able to collect a couple of rails of parts that members of our group could use in their projects.

By the time we got ready to leave, we had, in addition to the Micro Chroma 68 kits and the hardware we had purchased, something of an agreement that many of the students in our group would be working on projects for Motorola over spring break and the summer holidays.


Julia wrapped my arms around her as we stood facing the moon on the sidewalk outside her house about a half hour before midnight. Neither of us spoke for maybe a couple of minutes, then she turned and gave me a kiss that must have lasted as long. It tore me up to tear myself away so we could unload her hardware.

Her mother was sitting on the couch with some knitting when we entered the front door.

"Mom, don't say a thing."

"About what?"

"About it would be faster and easier for me to stay over in Joe's spare room. 

"But that would mean Dad wouldn't be able to help you build your computer." She smiled. "We're putting enough pressure on you two. Take your time and don't mind us."

Chapter 14.4: Rocks -- what?

[Backed up at]

Monday, September 14, 2020

33209: Rocks -- Moving Ahead

Chapter 14.1 Rocks -- Bit Multiply

Chapter 14.2: Rocks -- Moving Ahead

[Please pardon the layout change. Google is being the 800 pound prima donna and making all blogspot users use a buggy blog editor now.]

"Are you sure that there's nothing in what you and Julia just went over that you won't be claiming as IP?" Bill wrinkled his forehead.

I shrugged. "Trying to claim IP on this kind of thing is only one step beyond trying to claim IP on binary addition. No real circuitry to base claims on, nothing but ideas and math."

(We won't mention a very famous, wealthy corporation that did, in fact, attempt patent claims on binary addition in an ALU, buried in its claims concerning a programming language and programming environment they developed and sold. We also won't dwell here on the fact that, once upon a time, ideas, math, and algorithms were considered well outside the domain of patents in the USA.)

"Would it be possible," I asked, pressing my own agenda, "to reduce the cycle count to one on reads and two on writes in the direct page RAM, without blowing the transistor budget on a 6805 or 6801? That alone could better than double the speed of software multiply and divide."

There was a bit of uncomfortable chuckling and clearing of throats.


Several engineers looked at Pete. He shrugged.

Tobias tilted his head apologetically. "We'd have to fix the prefetch/decode circuit so it's a real pipeline of depth one."

"It's not a real pipeline?"

 "The eight-bit designs don't have a place to keep the instruction in its partial and fully-decoded states, so we go back and redo the prefetch if we don't use it immediately." 


"And then we'd have to test it. Testing is what we get stuck on budgeting time for. You should talk with your brother about that."

"Denny's not in charge of test, is he?"

"No, but he could tell you something about the backlog."

Our Bob spoke up, "Could interns help with the grunt work?"

Motorola's Bob exchanged glances with Bill, then turned to Jesse. "Should we look at that?"

"Maybe we should," Jesse frowned. "I'll discuss it with my group on Monday, see if we can separate something out that a non-engineering tech could handle."

"Remember that these guys seem to have a bit more of a handle on the tech than our usual crop of interns."

"We'll take that into consideration."

I ventured a bit further. "I'm not just thinking of fast direct-page RAM, though. The 6809 and the 68000 have enough index registers to support separating the parameter stack from the return pointer stack, and that means one might profitably attach a hysteric cache to both pointers, with the appropriate control signals."

That got me looks of confusion and amusement.

"I mean a cache that tracks the stack pointer with hysteresis." I borrowed Julia's notepad again and sketched out something like this:

Ms. Philips reached over and lifted the notepad and waved it at me. "I am sure this is IP."

"It's just a lousy diagram of spill-fill cache tied to a stack pointer. Calling it hysteric is a bit of a pun, is all. Not even a really good pun, at that."

Jesse started chuckling. "If it works," he commented, "it'd be more appropriate to call it an anti-histrionic stack cache." 

A number of other engineers echoed his chuckles of appreciation.

Ms. Philips and Ms. Steward put their heads together and started working on something. Bill and Motorola's Bob refrained from comment, keeping an unobtrusive eye on what they were working out.

I added, "If such a cache could also be accessed in single-cycle reads and two-cycle writes, local variables would be almost as good as registers."

Bill leaned forward. "We've taken a lot of your time on this blue-sky brainstorming, but Bob and I wanted to get your opinion on something."

I let the amusing, but perhaps meaningful mixed metaphor pass and nodded.

"If you were designing a mass-market personal computer using an existing CPU, would you use Intel's 8086 or 8088?"

It was my turn to be confused. "Maybe I should give it more careful consideration, but my impression is that instruction set is an improvement over the 8080, but not much. And it has those sloppy segments. No. I'd use the 6809 for its instruction set, addressing modes, and register set before I'd use the 8088, even though the 6809 is a bit slower on multiplies and a lot slower on divides, and, for a PC, would require bank-switching or the 6844 MMU. 

(PC? I had become accustomed to the abbreviation in Japan while I was there as a missionary. How quickly people forgot, in our real world, that there was more than half a decade of PCs before the IBM PC.)

"And I'd use the 68000 over the 8086 even though the 68000 costs a bit more, because the 8086 just doesn't make sense as a design. It requires 16 bit wide memory, but it still gives only 16 bit addresses unless you play bad programming practices games with your code. Sloppy segments are a bug generator and a security booby-trap."

Bob nodded. "Are you sure your antipathies are not colored by family loyalties? The tech industry doesn't forgive misplaced family loyalties."

"Family loyalties may induce some of the heat, but, really, if they want to map 16-bit logical addresses into a 20-bit physical address space, they should make the segments fully 20 bits wide. 24 or 32 bits wide would make even more sense, even if the top four or twelve bits aren't brought out of the package or don't even physically exist. And the segments should have limit registers, as well, if they're going to mean anything besides crude bank-switching with the improvement of being able to tie specific banks of memory to specific index registers, including the instruction pointer. Half-baked MMU."

"But potentially useful, no?"

"With extreme caution. Too much caution, really."

"How about segment registers for the 6809 or 68000?"

"You can use the 68000's address registers for segmentation if you want, although the segment limit problem remains, and there is a memory cycle penalty if you don't handle the segments well."

I stopped to think my next words through.

"If I were adding segmentation to the 6809, I'd want full 32-bit segment registers. The limit registers would be as wide as the index registers, so if you had a derivative with only 16-bit wide index registers, the limit registers would also be 16-bit. Instead of a segment override prefix like the 8086, I'd just have the register-to-register transfer instructions move the segment and limit registers, as well."

Bill and Bob were both nodding. Bill asked, "You've taken a look at the 68008, haven't you?"

"Yeah. But I'm letting Mike be the one to have fun with it."

Mike snickered.

"If it were available in, say, three months, in small lots, would you use it?"

"There are a lot of things that a 4 megahertz 68000 is going to be no faster doing than a 1 megahertz 6809, because of the memory cycle speed, the extra width of instructions, and other things. Many of those things are precisely what a personal computer is going to be used for, at least for the next several years. A 4 megahertz  68008 is going to be about half to two thirds of the speed of the 68000, I think. The only advantage is the megabyte address space, which really won't be quite enough in the near future."

Bill and Bob both frowned.

I continued, "Now, if we had a further evolution of the 6801 with an additional 8 bits attached to the top of the index register and program counter, a long jump, and either a long load of X or a transfer A to XHi or some such, at a price not too much higher than the 6801, that would make a good cheap personal computer. Or my pet imaginary evolved version of the 6809 with PC, X, Y, U, and S extended by 16 bits and new indexing modes to make the long addresses accessible, at a price not too much higher than the 6809, that would be ideal for the current market."

"One megabyte is too tight?" Bob asked.

"64 kilobytes is too tight?" Bill asked.

"Look at the 6847. Julia and I and my sister write reports using that because we are patient with the narrow window on the text, and we like the ability to type, think, erase, and type again. But my mom just gets frustrated, and my dad barely avoids going to sleep using it. People with no reason to be patient won't get it, and they are the ones who will be buying most of the personal computers sold. A personal computer has to be able to show the equivalent of a typewritten page on its screen, at minimum, or at least have a clear upgrade path to get there. That's what's stalling Radio Shack's Color Computer in the market right now. Besides lack of MMU."

Pete said, "But a typewritten page of text would only need a 2 kilobyte screen buffer. I've seen the Japanese personal computers, and they're pretty functional with only 16 bits of address."

"How functional?"

 "All the useful characters."

"Not by a long shot. Less than two thousand. The real count for a good newspaper is estimated at over 3,000 characters, but they aren't taking into account that what will be included in that 3000 will vary from month to month. And even newspapers will use really oddball characters regularly, when they need something more precise in meaning, and if you include the ability to display all the oddball characters, you're well into 9,000 characters or more. Add historical characters and you easily triple that count. Chinese is on the order of a hundred thousand characters. Sixteen bits doesn't cut it, except for very limited purposes like cash register receipts and utility bills."

"You can't be serious."

"I've lived over there. I know the hype they give the current crop of PCs and the sell-job they give the new student of the Japanese language, and I know the reality when you start reading serious literature. The standard character set is just enough to get started."

"How does anyone remember them all?"

"They don't, but that's going to be one of the things a real personal computer will be good for, helping them find and use the ones that they have trouble remembering. The personal computers they have now are very limited in scope relative to what they need, and what they will have in the future. They sell because they don't have anything better."

I continued after a moments' thought, "If the characters are to have decently defined glyphs, you want bit-mapped characters that are 32 by 32 pixels, not 16 by 16. 10,000 characters at 128 bytes per glyph is going to eat up a megabyte of address spaced pretty quickly." (Vector glyphs were still a bit exotic for a conversation like this until a couple of years later.)

"And graphics." I pointed at the TV. "How many kilobytes is the graphics mode screen buffer on the 6847, for just fuzzy monochrome on a color TV?"


"How would the same resolution graphics in four colors be, if the 6847 supported it, or if you modified the output and added the RAM?"

"An extra bit per pixel, so twelve."

"That takes 12K out of the program space on the 6801 or 6809, just for four colors, and everyone will want a much bigger gamut of color. And resolution at least double what the 6847 offers. 64K was tight to start with, and a megabyte will soon be tight for color graphics. One advantage, I guess, to the 68008 is the implicit upgrade path to the 68000, but 24 bits of address will shortly be too few, also."

"16 megabytes too tight? RAM is expensive," Sharon pointed out.

"If you don't want to be a foundry for other companies' designs, you have to have a base technology where you develop your testing and manufacturing techniques. That's RAM. It pays for itself without even being on the market by helping you get your other products right, faster."

"That kind of thinking'll push the price of RAM right through the floor," Motorola's Bob said with a frown.

"Exactly. But you won't care, because RAM pays for itself in shortening your development cycles for your profitability products. RAM should be like candy, anyway."

"RAM should be like candy." Bill harrumphed. "I think you've said that before." He reached into his briefcase and pulled out an advanced information datasheet and handed it to me. "Has Denny shown you this?"

The datasheet described the planned 68010 and 68012. I scanned it quickly. "No. Can Julia and Mike also take a look at this?"

"Sure. And anyone else in this room, really."

I showed Julia the changes in the addressing mode, allowing 32 bit constant offsets, and the short loop cache mode. 

She tilted her head grinned apologetically. "I guess it's an improvement?"

"Definitely. And the exception frame looks more manageable."

I passed it to Mike, and Bob and Jennifer looked over his shoulder. 

After a quick scan, he looked up. "Why isn't the 68008 based on this? The short loop execution mode would be especially useful when memory's only eight bits wide."

"Timing. Market and management." Bob shrugged.

"If I were you guys, I'd hold the 68008 off until I could make it an 8-bit version of the 68010. In spite of the fact that I personally really want to get my hands on one."

I nodded my agreement with Mike. "Or, if you just have to have an eight-bit 68000 now and this allows testing to complete more quickly, plan and advertise a 68018 that will be an 8-bit 68010."

"What if we have plans for adding more addressing modes and wider math, and dropping the loop mode for a small general cache, in another CPU in the early planning stages?" Bill's face was unreadable. "Not saying we do, but what if?"

I took a deep breath. "You know, in the 6809, extended mode was added to the index post-byte for doing memory indirect on absolute addresses. I'm wondering how much more it would have cost to included direct page in the index post-byte, as well. That would allow using the load effective address instruction to get the address of a direct page variable without using the accumulator, which would make the direct page much more useful for statically allocated local variables. But adding many more addressing modes would quickly get into negative trade-offs."

"But that's talking about the 6809."

"Yeah. The 6502 needs two kinds of memory indirect because it's so register poor. And those two kinds were a very strategic choice. The 68000 already effectively has both kinds, because it has lots of indexable registers. It doesn't need more addressing modes, not considering how much it will cost to test and get right. Except for the 32-bit constant offsets, those will be worthwhile. And it especially doesn't need addressing modes that can be as quickly executed using existing instructions and a register or two. I'd have liked it to have memory indirection, but that's just an address register load, so maybe not really worth it. Sure, eight address registers is a shade tight for some uses, but you don't want to clutter the upgrade path to a 64-bit CPU with a bunch of new, untested addressing modes."

There was a chorus of cleared throats and exchanged glances.

"Would it cost too much to somehow allow engineers to experiment with variations of your primary designs, to push the envelope with real hardware, even if it's not tested?"

"What do you mean?" asked Bill.

"Like a skunkworks, but officially supported."

Motorola's Bob leaned forward. "Assuming we dare put our fab facilities at risk, where are we going to get the manpower?"

"Just let your engineers take up to eight hours a week on blue-sky projects on company time, no questions asked."

Sharon shook her head. "We're already short of time."

"Blue-sky projects give you a chance to figure out better ways to do things. You'll end up being more efficient and closer to on-schedule."

"Hard to believe," Pete complained.

I shrugged. "Well, you guys have the experience, not me. I've said my opinion."

"Okay, we have another addendum." Ms. Philips and Ms. Steward looked up from their writing and interrupted, and Ms. Philips showed Bill what they had. He passed the addendum to Bob, and Bob looked it over and passed it to me.

It consisted of mutual permission to use ideas and concepts we had talked about over the course of a couple of hours that night with a promise of best effort to offer each other consideration. The five of us figured that was more than agreeable, and added it to our agreement contracts.

As we wrapped up, Jesse asked me, "Could you put a Forth interpreter on a 6805?"


"Of course."

Julia looked up from the notes she and Ms. Steward were arranging to make copies of. 

"Self-hosted?" she asked. "That's where the language runs on the same processor that compiles the code, kind of the opposite of the cross-assembler that runs on the 6800 but produces code for the 6805?"

I nodded. "Yeah. Maybe self-hosted could be done, if you have enough ROM and RAM. The virtual instruction pointer needs more than 8 bits, but self-modifying code might work -- using an extended mode jump where the code writes over the jump address before executing the jump. Cheating, but it might work."

Jesse smirked and I chuckled.

Julia asked, "Can you show me an example?"

She handed me her pad again, and I wrote out some code:

   LDA IP+1
   STA SELFMO+2 ; direct-threaded
   JMP $EEEE ; provisional target address
* The 16 bit address $EEEE just got overwritten by the target address. 

She looked at it with a frown. "What's the purpose in this?"

"It's the part of the virtual machine emulator where the CPU calls the code to emulate each virtual instruction. And each emulation routine ends in a jump back to NEXT."

She tilted her head. "Sorry. I'm totally lost."

"For example, the routine to add two numbers on the stack would look something like this:

   LDX USP ; parameter stack
   LDA 3,X ; low bytes
   ADDA 1,X
   STA 3,X
   LDA 2,X ; high bytes
   ADCA ,X
   STA 2,X
   INX ; drop argument
   STX USP ; update the stack pointer
"The routine for a jump would look something like this:"

   LDX IP ; IP is pointing at the in-line offset.
   LDA IP+1
   ADDA #2 ; bump past offset
   ADDA 1,X ; add the low byte of the offset
   STA IP+1
   ADCA ,X ; and the high byte

"And the routine for nesting calls would look something like this:"

   LDX RSP ; return address stack
   DEX ; room for old IP
   LDA IP+1
   ADDA #2 ; bump past call address
   STA 1,X ; tuck the address to return to away
   STA ,X

And then I was stuck. "Wait. This isn't going to work."

Jesse chuckled again.

I went back to the NEXT routine. "Yep. I'm forgetting to actually get the jump address in the NEXT routine, and maybe a bit more."

Jesse agreed with a grunt. 

I shook my head and laughed. After staring at the code for NEXTIP for a minute or two while Jesse smirked and Julia looked puzzled, I shook my head. "Not having a sixteen-bit pointer is a real pain." 

Julia met my eyes and sighed. "Don't worry about it. I don't think the eight kilobyte maximum address space is going to leave much room for a program to run in, anyway."

"Yeah, but they're going to eventually make a chip with a full sixteen-bit wide CPU. I want to convince myself of this."

Her forehead creased.

"We need to grab two bytes pointed at by the sixteen bit IP in the direct page."

   LDA IP+1
   JMP $EEEE ; provisional target address
* Had to overwrite lots of addresses.
I sighed. "And all of that in the small RAM is going to run us out of RAM."

Jesse let out a horse laugh.

"I guess this needs to be done a bit more simply."

"No. I think you nailed it. But put the code from NEXTIP to NXADD1 in ROM, followed by a jump to NXADD1 in RAM." He continued to chuckle.

Julia said, "It's okay. I don't care. We're all tired. Let's go home, or, well, back to your brother's place."

"But I want to work the rest of this out. Borrow from ..." 

She took the Forth listing I had picked back up and her pencil and the sheet of paper I was trying to work on out of my hands while Jesse laughed. 

"You got a real jewel there, Joe," he said. "You'd better listen to her. And don't worry about the Forth on the 6805. I think that's about as good as it gets, and as Julia says, it's not much use until we have a 6805 MPU with fourteen bits or more of address. And I look forward to working with you as an intern, and having you join us when you graduate. I like the way you think. I think we all do." He looked around at the engineers and his managers, and everyone nodded in agreement.

I suddenly turned Japanese and ducked my head. "Sorry. I mean, thanks."

[Backed up at]

Tuesday, September 8, 2020

33209: Rocks -- Bit Multiply

Chapter 14.0 Rocks -- 2805

Chapter 14.1: Rocks -- Bit Multiply

Julia caught my eye with a puzzled look.

"Gotta question?"

She nodded. "The 6805 doesn't have a multiply instruction."


"Neither does the 6800."


"Tiny BASIC and Forth don't multiply 12 by 10 by adding twelve up ten times, do they?"

"No, ..."

"Does it have something to do with that bit multiply you were talking about?"

I looked around at the group of engineers, managers, legal staff, and students, and asked, "Can we take a detour?"

Bill leaned back with an expectant smile, his hands behind his head, and nodded.

Motorola's Bob said, "Go ahead."

"Can I borrow that Forth listing back?"

Bill picked it up and handed it to me without comment.

I opened it up and leafed through it until I found the USTARS routine on page 17 (SCR 23). I read through the routine, thought for a moment, then set it back down, reaching in my shirt pocket for a pencil that wasn't there.

Julia turned her notepad to a blank page and handed the notepad and her pencil to me.

"Thanks. Say we want to multiply two eight-bit numbers. I'm going to arbitrarily pick eleven and five." I wrote the two numbers down in binary and decimal, vertically, for multiplying by hand, then proceeded to work the product out. "I'll use the method we usually use for decimal, multiplying the multiplicand on top by each column of the multiplier on bottom, and adding them up:

            00001011 => 11 (8+2+1)
          x 00000101 =>  5 (4+1)
-- -------- --------   ---
            00001011 => 11
          0 00000000 =>  0
         00 00101100 => 44 (32+8+4)
(Abbreviating the zeroes.)
-- -------- --------   ---
 0 00000000 00110111 => 55 (32+16+4+2+1)

Julia held her hand out and I gave her back her notepad and pencil.

She proceeded to write out a decimal product:

   x 4321


Mike grumbled, "Grade school."

Julia gave him a glare. "Looking at the fundamentals so I can understand what the computer has to do, Mike!"

He shrugged.

She turned back to me. "Okay, I think I can see how you're doing basically the same thing both ways. So multiplying each column in binary is what you are calling a bit multiply?"

"Sort-of. Maybe. Perhaps more a bit multiply-and-accumulate instruction."

She shook her head with a blank look and handed me back her notepad and pencil.

"Hmm. Let's look at  how the Forth multiply routine works. It says it multiplies the top two 16-bit words on the stack, and puts the low 16 bits of the result back on the stack, keeping the high 16 bits in A and B." I picked the Forth Listing back up and copied the routine out, modifying the comments:

    LDA A    #16    ; bits in a word (two bytes)
    PSH A    ; counter in temporary on stack
    CLR A    ; ready to accumulate the product
    CLR B    ; clears carry
    TSX    ; point X to the parameter stack
USTAR2     ; top of loop
    ROR    5,X   ;  shift multiplier, pull last carry in from result
    ROR    6,X   ; leaves low bit of multiplier in carry
    DEC    0,X   ; count down -- leaves carry alone
    BMI    USTAR4   ; counted out?
    BCC    USTAR3   ; skip add if low bit is 0
    ADD B    4,X   ; low bit is 1, add
    ADC A    3,X   ; now carry is carry from add
    ROR A    ; shifts carry from add into result
    ROR B    ; shifts low bit of accumulator into carry
    BRA    USTAR2   ; next bit
USTAR4    ; counted out
    INS    ; remove counter from stack

Julia shook her head.

I grinned. "Yeah, it looks like it's out of phase with itself, but that's because it's reusing the multiplier variable to pick up the low bits of the result. Saves space on stack and saves some shifting instructions."

"Out of phase?" Now she gave me a moue.

"Like the loop starts part-way through, because it kind of does. Hmm. Let's write a loop that would look more like what we do on paper." I stopped to think, then started to write and erase and rewrite.

"To avoid confusion, let's not use any tricks. In fact, let's not use the S stack for parameters, either. But there will be one sort-of-trick, shifting the value down in the accumulator is the same as shifting the calculation window up."

"Oh-kay ..." But she looked even more perplexed.

Here's what I ended up with:

* Multiplicand at 2,X:3,X
* Multiplier at 0,X:1,X
    LDX PSP ; parameter stack
    DEX ; allocate work space
    STX PSP ; just in case
* Multiplicand at 7,X:8,X
* Multiplier at 5,X:6,X
    LDAA #15
    STAA 4,X ; bit count
    CLR 3,X
    CLR 2,X ; result low word
    CLR 1,X
    CLR 0,X ; accumulator, result high word
    CLC ; known state
    LDAA #1
    BITA 6,X ; low bit of multiplier
    LDAB 1,X
    ADDB 8,X ; multiplicand low byte
    STAB 1,X
    LDAB 0,X
    ADCB 7,X ; multiplicand high byte
    STAB 0,X
    DEC 4,X
* Relativity --
* shifting the contents right is same as
* shifting the calculation window left.
    ROR 0,X ; moves carry into accumulator
    ROR 1,X
    ROR 2,X ; shift into low word
    ROR 3,X
    LSR 5,X ; shift multiplier down
    ROR 6,X ; for next bit test (relative shift)
    LDAA #3 ; 4 bytes to copy
USTARC ; copy result back into stack
    LDAB 0,X
    STAB 5,X
    INX ; drop count from stack
    STX PSP ; restore parameter stack pointer

She looked the code over. "Do you have to save and load accumulator B every time through? Nothing else seems to be happening to it and it would save instructions and time."

"Nope. True. And yep. It would."

"And," she paused, "could you use an ANDA instead of a BITA to test the low bit of the multiplier, since you reload it each time through?"

"Sure. Or, if we had another 16-bit accumulator to hold it, we could use the bit test instruction and rotate the bit to test instead of rotating the multiplier down."

"Hmmm. In the Forth code, shifting the multiplier right and testing the carry is another way of testing the lowest bit, isn't it?"

"That's right, and it does save a few more instructions."

"On the 6805, you could use a branch if set instruction, couldn't you?"

"I was afraid you were going to ask that."

"It wouldn't work?"

"Well, the multiplier has to be addressed as a direct page variable if you use the BRSET or BRCLR instruction. I assume you would use BRCLR. Other than that, it should work."

She thought for a minute. "Okay, so using global parameters instead of passing them on the stack, ...," and started writing.

    ORG $80
    ORG $200
    LDA  #15
    CLR ACCM+1
    CLR ACCM+2
    CLR ACCM+3
    CLC ; known state
    LDA ACCM+1
    STA ACCM+1

"And an 8-bit multiply probably wouldn't have to save and load the accumulator?"

"I think it wouldn't. This code looks good, let's test it later."

She thought some more and started writing again.

USTAR    LDX PSP ; parameter stack
    DEX ; allocate work space
    DEX    DEX
* Multiplicand at 5,X:6,X* Multiplier at 3,X:4,X
    LDAA  #15
    STAA  2,X ; bit count
    LDD #0
    STD 2,X ; result low word
    STD 0,X ; accumulator, result high word
    ADDD  7,X
    RORA ; moves carry into accumulator    RORB
    ROR 0,X ; shift into low word
    ROR 1,X
    STD  3,X
    LDD 0,X
    STD 5,X
    INX ; drop count from stack

"Did I get that right for the 6801?"

"I think so. Pretty close if not."

"So would an instruction that adds the source to the accumulator if the carry is set be your bit multiply?"

"Yes, but. Part of the reason I want the bit multiply is to save instructions extending the multiply to 32 bits or more. But if the bit multiply is add if carry set, I'm pretty sure you'll have conflicting uses of the carry."

"Oh. Adding the multiplicand is going to give us the carry from the addition, and overwrite the state of bit 0 that we put in the carry flag." She paused to think. So it would only work once."

"Myep. So it looks like the bit multiply would need to be based on the branch if bit 0 clear or bit test immediate 1 instruction, instead of testing the carry. And we'd want to be able to specify both the multiplier and multiplicand independently, too, if it's going to be extendable."

"And all it'd replace is just the branch and the add, so it would really only speed things up a little."

"Maybe so. If it's going to speed things up significantly, it also has to shift the multiplier and the accumulator. And the carry out of the bottom bit of the accumulator has to go somewhere, so there's a third memory argument. And shifting into low-order fields after the low-order fields have already been added and shifted is going to double-shift the low-order fields. The bits have to be fed forward the full width of the multiply. Maybe trying to make a single bit multiply that can be extended as far as we want is just not going to work."

"What if you don't shift the accumulator fields in memory?"

"I think that's going to make it hard to do one bit at a time, because the whole reason multiplying a bit at a time works is that we're moving that window across the inner products."

Ms. Philips cleared her throat. "Bob, have these two just shared things that should have been trade secrets?"

I looked up. "I'm sure your engineers have been down this road before."

Greg nodded. "We have. I must admit, it took me longer, but I was working by myself and making sure I had enough notes to explain to my manager why not, if I couldn't get a circuit that would work."

"Gate counts, power dissipation, that kind of thing?"


Jesse leaned forward with a grin. "Dang. And you two do this kind of thing for fun."

I grinned back.

Julia sighed. "He does." And she smirked. "Oh, it's kind of fun watching him go down the rabbit holes, and sometimes going down there with him."

That got more whistles and some "Hey, hey, hey!" comments.

[Backed up at]

Monday, August 24, 2020

33209: Rocks -- 2805

Chapter 13.8 Straits -- Intellectual Property Agreements

Chapter 14.0: Rocks -- 2805

Bill grinned sardonically. "Well, I think this will work out well."

(You may want to put your BS meter away for this chapter, or at least set the threshold level pretty high.)

Bob chuckled. "Stephanie, can you get together with Carrie and see that what these three signed gets replaced with a more appropriate agreement?"

"I'd be happy to, sir."

"The same as Joe and Julia's agreements, with an addendum for their projects?" Ms. Philips asked.

Bill answered for him. "Yes, yes, of course."

And Bob nodded.

Ms. Steward, Ms. Philips, Mike, our Bob, and Jennifer got together at one end of the table.

As Julia and I connected her mainboard to one of the TVs, I whispered to her. "I thought the two guys were from Motorola's legal department."

"I did, too," she whispered back. "Must be much higher up in management."

I nodded my agreement.

(No, I never even came close to meeting Motorola's Bob and Bill in the real world.)

A number of engineers came in, bringing in pizza and liquid refreshment.

"Your friends," Motorola's Bob said to me with a grin, "are having pizza elsewhere. I think we should have some pizza in here, too." He turned to one of the engineers. "Jess, I hope there's something non-alcoholic to drink?"

The engineer named Jesse started, and looked up guiltily from the six-packs he was carrying. "Erm ...."

An engineer on the other side of the room called out, "Denny made sure we had root beer, and I made sure we had some other options." He held up two-liter bottles of soft drinks. "Not all of us are fueled by beer."

"Good job, Tobe."

Tobias gave Bob a thumbs-up.

As we ate pizza and talked, we demonstrated what we had done so far -- the ROM menus, BASIC, TSC's debug system, and Flex, and using Flex to run Motorola's assemblers.

We shared some comments and discussion of the process of getting Flex to run on the Micro Chroma 68, and I described my dynamic RAM refresh circuit, explaining how I borrowed the video scan counter of the 6847, and mentioning the problems I had run into with my original design. I also explained the simplistic bank switching that made it possible to run Flex.

Several of the engineers commented on how my refresh circuit sounded similar to a circuit the engineers who worked with Radio Shack on the Color Computer had produced before they designed the sequential address multiplexor as a separate circuit. Not yet being familiar with the SAM, I couldn't comment.

Jennifer, our Bob, and Mike had taken care of their paperwork by then. Bob knew something about the SAM already, and he discussed it a bit with the engineers.

We showed them the 6801 daughterboard on Julia's mainboard, and her keyboard, and she described the way we were using the 6805 and its timer to scan and debounce the keyboard and control the hexadecimal display, augmenting the I/O with either latch or multiplexor.

Then she loaded Forth on her computer from tape and used it to send numbers out to her keyboard's hexadecimal display.

We stopped for a few minutes while Bob, Bill, and some of the engineers discussed whether Motorola wanted to ask us for permission to use the keyboard decoder/numeric display design and code for an application note, and the upshot was that they did, and the five of us agreed to discuss that with the rest of the group.

Most of the engineers were appreciative of Julia's Forth examples, and I explained what I had done to get the drivers to work, mentioning that we hadn't solved the disk problems yet for Forth.

My disk interface was the topic of considerable discussion, and Ms. Philips and Ms. Steward quickly produced a sharing addendum to allow us to get the schematics out for everyone to look at. Before long, Julia and I had another addendum to our agreements -- an internship contract for producing several tech notes on the use of the 6801 as a floppy disk controller. The addendum allowed Motorola the option of building a semi-custom "system on a chip" SOC floppy disk controller based on my circuits.

Denny had already shared the schematics Julia had drawn up from my scrawls with some of his friends. But now the context was Motorola, so the addendum was deemed wise.

"Ah, to be an undergrad with all the time in the world again," Tobias reflected jocularly. "Do you think you could get a 6805 to handle the floppy controller functions?"

I tilted my head and thought. "That would probably limit sector size, with X being only eight bits. Come to think of it, the size of X might require enough extra code to prevent the processor from keeping up with the data."

Another engineer, Sharon, asked, "What's your general impression of the 6805?"

"It does the job for little things like the keyboard controller," our Bob volunteered.

I concurred.

There was general approval of that analysis.

"But I miss stack support," I added.

"On an eight-bitter?" Jesse queried. "You'd prefer the 6502, maybe?"

Jennifer noted, "The 6502 is a clever design, but it belongs to MOS Technologies and Commodore, doesn't it?"

(In the real world, Motorola might have been smart to use their patent agreements with MOS Technologies and second-source the 6502 in the late 1970s. They did offer to produce SOC chips with the 6502 as the CPU core in the mid-to-late 1980s. But that history is not for this story.)

"The 6502 is a good chip," I asserted. "It straddles some boundaries like the 6809, but I think the way it does so constrains compatible upgrade paths." I paused for thought and emphasis. "Every application wants room to grow. Maybe some shouldn't, but many can profitably grow in scope and function. And growing software reliably wants things like code re-use by re-entrant subroutine call, and keeping subroutines re-entrant requires something like a stack that you can push to and pop from, for parameters and local variables. There's no push or pop on the 6805."

Julia added, "Even if you aren't calling subroutines a lot, a stack helps manage RAM. Global RAM is harder to keep track of, even if you never re-use any variables."

I turned and raised my eyebrows. "You're picking this stuff up."

"A little. Dad has been explaining things you haven't."

"Oh. Sorry. I'll have to do better."

"It's okay." She smiled. "He enjoys it. He always wanted his oldest child to be an engineer."

"Now I know why he likes me so much."

We grinned at each other, then Julia coughed discreetly.

I ducked my head and turned back to the engineers, several of whom were quietly clapping their hands, rolling their eyes, or pretending to give us wolf-whistles.

"Anyway, as Julia points out, a stack you can reference makes RAM much easier to manage. Of course, you can synthesize a stack, but synthesizing is slow, and a disincentive, and the code to support the synthesized stack is a distraction."

An engineer named Pete objected. "Moving up to the 6801 is not that hard."

"But it does require reworking a lot of the code, and checking all of it for side-effects of the differences between the two," I parried. "And there are the bit manipulation instructions in the 6805 that the 6801 does not have, easy enough to synthesize on the 6801, but still requiring time and effort. Adding stack support to the 6805 ought not to be that much of a change, and it would support quite a bit of application growth. That would give the customers' engineers much more confidence in choosing the improved 6805 for small projects with the potential to become large."

(The 68HC11, an evolutionary step from the 6801 that Motorola introduced in 1984, did have bit manipulation instructions. And the 6805 itself later evolved to the confusingly named 68HC08, which did introduce more complete stack support via instruction pre-byte escape -- single stack with stack indexing, as opposed to the dual stack and index marking I suggest  below. In the real world. Several years later.)

Jesse countered, "Okay, how do you propose to add stack support with minimal change? Pre-bytes like on the 6809 are too expensive for a pure eight-bitter."

(Well, they were just a little too expensive in the early 1980s.)

"Add a second stack register. Maybe call it U for user stack, following the 6809's register naming. Add push and pop instructions that push and pop to the U stack, and transfer instructions that allow moving U to X and back. And instructions to save U and restore it using the S stack. Eight instructions should do the trick."

Julia handed me a sheet of scratch paper, and I wrote down the additional instructions:
I drew out a map of the registers of the 6805, except for the condition codes:

6805 register b15b14b13b12 b11b10b9b8 b7b6b5b4 b3b2b1b0
A7A6A5A4 A3A2A1A0
X7X6X5X4 X3X2X1X0
SP:00000000 1(SP6)SP5SP4 SP3SP2SP1SP0

Then I drew out a modified map, including the U stack:

2805 register b15b14b13b12 b11b10b9b8 b7b6b5b4 b3b2b1b0
A7A6A5A4 A3A2A1A0
X7X6X5X4 X3X2X1X0
U:00000000 1(U6)U5U4 U3U2U1U0
SP:00000001 00SP5SP4 SP3SP2SP1SP0

"Keeping the stacks separate will allow moving the return stack out of the direct page. It could then be given its own port to the CPU, in its own address space, with separate on-chip address and data lines. That would allow proceeding to the next instruction while the call instruction stacks the return address. That way, calls should end up costing no more than jumps, and it should be possible to make the return operator faster, as well."

The comment about calls taking less time got some discussion of a nature too technical to bore you with here.

Except for the subroutine entry and exit protocol. "Subroutines," I continued, "could look like this:"
    LDA 0,X ; 1st parameter
    LDX 1,X ; 2nd parameter
    LDA 2,X ; 3rd parameter
    INX ; clear all parameters
"But X is only eight bits," an engineer named Wayne objected.

"The S register is only six or seven bits in the 6805. The return stack is so small it that it will run out of memory before it cycles through the addresses allocated to it in the direct page. But you can move it out of the direct page and no one would notice, and it could still be effectively less than eight bits to be decremented and incremented by the push and pop.

"If it weren't for wanting to sometimes directly shift local variables, and the lack of sixteen-bit index offsets for the unary instructions in the 6805, you could put the parameter stack outside the direct page, too. Putting it where the return stack is now should be no problem, at any rate, and allow access by unary instructions."

Several of the engineers started scribbling on scratch paper.

Sharon said, "This could be useful."

An engineer named Chuck intoned, "Room in the design for improvement is good engineering."

Bill asked, "Are you taking notes on this, Julia?"

"Is that okay?"

"Can we get a copy, and can we mark parts we don't want shared outside?"


"In that case, thank you, make sure you get Chuck's comment about room for improvement in, too, and please continue."

He and Motorola's Bob again exchanged silent words, and both nodded in agreement.

I shook my head and said quietly, "Julia, I presume upon you too much."

Julia grinned. "I'll claim my pay when we get back home."

I grinned back.

"Get a room!" There was a bit of chuckling. We had an audience again.

An engineer named Jack objected. "Isn't dedicating RAM to a second stack a waste?"

I shook my head. "RAM is easy to make and relatively easy to test, isn't it? Shouldn't it be cheap? Like candy. And the call stack doesn't have to be completely inaccessible. If it's in the extended address space, it would be accessible via extended addressing or 16-bit index offsets."

An engineer named Monty grumbled to himself. "Testing RAM is a good way to bring up new processes, too. Forcing the customer to scrimp on RAM is just a little anti-social."

Motorola's Bob chuckled at that, and asked Julia to quote Monty on it.

Jesse was also sketching something on note paper. "Separate address spaces. We could put part of the direct page RAM in its own address space and give it its own port to the ALU, and shave a cycle of access time for that area in direct page RAM," he muttered, half to himself.

Julia repeated, sub-vocalizing, "... shave a cycle for the direct page RAM access."

Jennifer overheard Jesse, and asked him, "Could that be done without making it difficult to speed the processor up?"

Jesse scratched his head. "Actually, if we're careful, it should make it easier to keep things in sync in a process shrink."

"I was thinking about overclocking."

Jesse chuckled. "Overclocking is one of those dirty secrets we don't talk about, but it can be used to predict whether certain aspects of a process shrink will work."

Our Bob joined him in chuckling.

"Is a process shrink where you make the masks smaller?" Jennifer asked.

Our Bob nodded.

Jesse answered, "It's more than that, but, yeah."

"Could that be used to improve access time to the parameter stack?" I asked.

"That would be a bit more complicated," he replied. "Might be too much beyond the concept of an eight-bit micro-controller."

"You know," I commented, "one thing I'd like to have is a way for the CPU to catch things when calls or interrupts try to push too much on the stack, and when return instructions try to pull too much off."

"How can you save state on the stack when the stack isn't valid?" Wayne asked in a tone that was almost rhetorical.

"Could you have a limit register for S that could trigger an interrupt when a call or interrupt would decrement S below it? The limit register could be set by the program, high enough to allow the stack interrupt room to save state without walking on variables."

Jesse looked up from his scratch calculations. "Shadow register sets that get switched in when handling interrupts could be a rather more elegant solution to the stack overflow conundrum."

Julia held her hand up. "Can you help me write that as a note?"

"Interrupts work like calls on our processors. They save the processor state on the call stack. That allows interrupts to nest, to a certain extent. A stack overflow interrupt would fundamentally be unable to nest anyway, so saving state somewhere else might make sense. Some processors have shadow registers --"

Our Bob cleared his throat and said, in a loud whisper, "Z-80. And the 68000's A7 system stack, although that's just one register."

"-- for fast context switches." Jesse chuckled before continuing. "Shadow registers might be one place where you could save the processor's state on stack overflow."

Julia and Ms. Philips conferred with Jesse and our Bob on this and Julia continued with her notes.

"Speaking of the interrupt stack," an engineer named Craig pointed out, "stacking the U stack on interrupts will mess with stack frame compatibility."

"That's part of the reason I call this ideal processor with conflicting specifications the 2805," I explained.

"Conflicting specifications," Motorola's Bob chuckled, and all the engineers joined him.

Julia looked at me in puzzlement.

Tobias explained with a grin: "Conflicting specifications is part of what makes engineering fun." That got more chuckles.

"Giving the processor another name would help let customers know not to expect perfect compatibility," Wayne nodded. "But it also might make sense to not automatically save the U stack pointer." He frowned in thought.

"Assume the interrupt handler routine will behave nicely with the interrupted routine's parameter space, or switch it out itself?" I asked.

"Something like that. There won't be a lot of RAM to switch the stack around in, in a 6805."


"So, while we're critiquing the 6805, is there anything else?" Motorola's Bob asked.

"Not enough I/O pins. We had to use either an external 8 bit latch or an external multiplexor to get enough I/O bits to read 64 keys and communicate with the main CPU. If we had a package with sixteen more bits of I/O, we could decode larger keyboards without external parts and still give a parallel interface to the main processor. A serial keyboard interface could be done with fewer, but it would still need more than we have."

Julia looked up as she handed Ms. Steward another page-full of notes. "Serial keyboard cables will be better for office computers anyway, right, Joe?"

I agreed.

Jesse nodded, too. "Flatpack can give 64 pins in a reasonably small package. Socketing those is expensive for now, but surface mount is cheap."

Julia stopped him for explanation, and he drew pictures for her. "Flat-pick looks more like a square black chip than a millipede. Contacts on the edges like this. Sockets for them look like cups, but they are often soldered flat on top of the circuit board."

"So separate parts might actually be a better engineering option?" I asked.


"Anything else?" Motorola's Bob prompted.

"Daydreams?" I laughed.

"Sure." He grinned.

"The 6801's eight-bit multiply is useful. A pair of eight-bit divides -- integer and fractional -- might be useful, too. But I'm thinking about a complete one-bit multiply and one-bit divide."

He furrowed his brow. "Single bit? That seems like swimming against the current."

"Software multiplies spend a lot of time in branch instructions. If you could do a full single-bit multiply with one instruction and stack those instructions up, you could cut the time for a multiply to maybe a quarter of the time of a software multiply on the 6805 and 6801, without the complexity of a full multiplier circuit. You could get similar improvements with a single-bit divide."

(Again, many versions of the 6805 ended up getting a full 8-bit multiplier circuit, and the 68HC11 ended up getting both the 8-bit integer and fractional divides, in the real world.)

Craig responded. "Which algorithm, and how are the arguments addressed? Several known pits to fall into, but it might be worth looking at again."

Bill had picked up the Forth listing, and was looking at the first page.

"This is the license for using Forth?" he asked.

"For the Forth Interest Group's model interpreter," I replied

Monty explained, "There are many Forth development systems with more traditional licensing. The Forth Interest Group uses the liberal license and some of the models are known to be a little buggy in places. In some cases, it's almost as if they just threw code over the wall and abandoned it."

"How do you mean?" Bob asked.

"A liberal license requires an active development team to be useful. The development team can charge to fix bugs. But their model interpreter for our 6800 has nobody following up on it."

Bill laughed. "There's something cynical about giving code away for free and charging to fix bugs."

Monty shrugged. "On the other hand, the user is also able to look for and fix bugs himself. I saw this work at MIT. The group that works with the liberally licensed LISP interpreters only allows contributions that are liberally licensed into their code base. It's a rather elegant approach to sharing. Code that doesn't get used doesn't get fixed."

Bill's forehead wrinkled. "Elegant and efficient. Survival of the fittest. Hmm."

(I should note, I was actually as prescient as the me of this chapter -- two or three years later in my college career in the real world.

And we should also assure ourselves that the real engineers who worked for the real Motorola were aware of pretty much all of this.

Which path is best is often not clear. Motorola's management in the real world made decisions that, in hindsight, appear to have been counterproductive. Examining certain of those decisions is part of my reason for writing this story.

Hindsight does appear to be clearer than foresight, which is precisely the reason that this story is something of a waste of time, in effect, an idolatry of idealized abstract mathematical machines.

But if we are comparing ways to destructively waste time, I think it's less a waste of time than body pornography -- that's essentially an idolatry of idealized bodies. Modern pornography adds saccharin personality to the mix. Some rich person's ideal, not real, imaginary value only.

Speaking of the real world, of course you know, in the real world, Motorola's management and engineers had no reason to do blue-sky brainstorming like this with me, much less believe my ideas. But for this experiment to work, in the world of this novel, they must.)

[Third version backed up at
First and second versions backed up at]

33209: Straits -- Intellectual Property Agreements

Chapter 13.7 Straits -- The Road to Austin

Chapter 13.8: Straits -- Intellectual Property Agreements

"Ms. Philips."

"Hi, Joe, Julia. We're glad you could both make it."

We were in a conference room that seemed large for just Julia, me, Ms. Philips, and the two men in suits flanking her, whom I supposed were from Motorola's legal department. Two small stacks of papers and a legal-size note pad lay in front of Ms. Philips.

"We seem to be underdressed," I began.

"No problem. You've been on the road, we didn't tell you what to expect. But if it's okay, we want to take video of our meeting again for management." She pointed out the cameras.

Julia and I both nodded.


"No problem."

Ms. Philips continued, "Management also wanted to get non-disclosures and some other IP agreements signed."

I checked with Julia and she gave me an inquisitive look.

I shrugged and turned back to Ms. Philips. "I guess we missed something here. We need NDAs and IP agreements?"

"Ahh ..." Now it was Ms. Philips turn to look puzzled. She turned to the man on her right.

"There are some chicken-and-egg problems here," he replied to her unasked question.

"Can't talk without agreeing not to talk?" Julia asked.

I nodded once in concurrence. "I don't know why we should need that kind of agreement. I'm just some guy taking tech courses at a podunk college in west Texas ..."

"Hey!" Julia gave me an elbow and a sharp look.

I returned her look of reproach with a look of chagrin. "Okay, not podunk, but definitely not a big name like MIT, or even moderately well-known like Renssalaer Poly or Texas Tech."

She gave me another sharp look and I closed my eyes and nodded resignedly."I don't mean to disparage OC. It's a good school. But I don't think I'm doing anything special. Whose toes did I tread on?"

Julia sighed.

Ms. Philips laughed. "Not treading on toes. Just, well, it's a competitive industry, lots of players, not enough customers to support them all."

"Masaka." I shook my head. "Amortize the development cost and push the price down, and people'll be putting microcontrollers in everything. There won't be any bounds to the market."

None of the three sitting across the table from us commented on that.

"But I guess boards of directors start talking about market limits when they want control, and computers do carry that cachet of the mirage of control. I really must have tread somewhere too close to something, but I assume we can't expect an answer to that without a non-disclosure agreement?"

The man to Ms. Philips's right cleared his throat with a cough.

The man to her left said simply, "Please don't jump to conclusions."

"I guess I should have gotten Denny to give me more specifics." Julia and I both leaned forward to stand. "I'm not sure what I, uhm, we expected, but I feel like we've been caught out of position."

Now the man to her left smiled and waved for us to sit back down. "I must apologize. We should have coordinated better. Carrie, can I get a look at the paperwork?"

The man at her right frowned.

Julia and I both hesitated between sitting and standing.

"Sir." Ms. Philips handed him the stacks of papers.

He scanned them quickly. "Stock NDAs for new hires. Not appropriate here."

"Bob, ..." the man to her left began, and they exchanged an unspoken word or two before he leaned back with an air of dissatisfaction.

"Sir," Carrie pointed to certain paragraphs on the first page of one stack, "I edited these clauses appropriately, made some substitutions and deletions, and changed the document ID." She turned to the next page to show more.

Bob stopped her. "I'm sorry, Carrie, I should have taken a more direct hand in this. Do you have a legal pad?"

She handed him her legal pad

He turned to some blank pages and wrote too quickly for me to follow upside-down without making myself too obvious. "Make it simple, limit it to best effort to avoid representing themselves as being privy to Motorola's plans until two years or superseded by other agreement. And state that we'll give our best effort to refrain from using their work without permission."

He looked up at me. "We'll take the responsibility of avoiding exposing you to sensitive materials, if you'll be responsible for not sharing things you don't want us to see. And if we need to share something, we can make specific agreements." He turned again to Ms. Philips. "You can add a clause about special agreements, as well."

Julia and I exchanged looks again.

Julia said, "I might be able to sign something like that."

I nodded in agreement, and Carrie stood and moved to a stenographer's typewriter in a corner.

The other man cleared his throat again.

"Okay, Bill, Let's hear it."

"Bob, you know that's going to be a lot of work to go through every time we want to work together on something new. Clumsy. And the board will raise Cain about lost revenue."

"Bill, you know as well as I that expected revenue can't be dealt with as revenue until we have legitimate reason to expect it, and NDAs and NCAs do not provide that reason. The board may not want to listen to sound economic principles, but there is no loss until there is something to be gained."

"I agree with that." Bob nodded.

"We have some good processors."

"Of course."

"But every time we get some grass-roots excitement going about our processors, we've  been having the engineers sign non-disclosures and non-competes, and suddenly all the market excitement evaporates into the long tail of big projects. I think we've been cutting off our corporate nose to spite our corporate face --"

"You've said that before."

"-- killing the goose that lays the golden egg." He turned to me. "Pardon the expression."

I grinned. "I don't see a problem with the expression, as long as it remains metaphor. And I probably agree about NDAs and NCAs as not being what they appear to be. I'll need a lot of leeway if I'm going to keep the group we've got motivated."

I checked with Julia, and she smiled and nodded. "I'm with Joe on that." She reached out and gave my hand a squeeze.

"Thanks for being patient with us."

Bill nodded with a still-dissatisfied attempt at a smile. "Well, while we're waiting for some new documents, how was the trip?"

We offered a few details of the road down and the weather, but didn't mention the undercurrents. Both men were amused at the idea of five adults packed into a subcompact station wagon for six hours. Even Ms. Philips chuckled a bit while she typed.

"You didn't happen to bring the computer you're working on?" Bill asked, somewhat out of the blue.

Bob lifted an eyebrow. "I don't suppose there was room in that car."

"Actually, we did."

"Would you be willing to let us take a look at it?"

"Bill, I don't know if we want to expose the company too fully to their work just yet."

"There's nothing I consider proprietary in it. How about you, Julia?"

She nodded. "I trust your judgement."

Carrie took a page from the typewriter, and brought it to Bob. "What do you think?"

He read it carefully, then handed it to me. I put it between Julia and me, and we read it together.

"I think," I said, "it'll give us the room we need to work and allow you to protect Motorola's interests."

"Joe, shouldn't it mention existing work, and avoid making claims for the group?"

"Ah, yes. Of course."

With Julia's input, we added wording for existing work, a disclaimer relative to the group, and an addendum describing what we and the group had done to that point. With a bit of discussion we found wording we could all agree on. Then Julia joined Ms. Philips at the typewriter.

Bill asked, "So, can we get a peek at what you've done?"

"I think it's okay, Joe," Julia said from where she and Ms. Philips were working. "Why don't you go ahead and bring them in?"

"Them?" Bob asked.

"Julia's and mine."

Bill and I went out to the car and brought the computers in. When we returned, Bob had brought in a couple of color TVs to use as displays.

Julia and I looked over the completed agreement together, then faced each other, communicating silently.

"If you'll excuse us a minute," Julia said.

"Sure," Bob nodded.

"Do you need a place to talk alone?" Bill asked.

"If it's okay."

Ms. Philips opened a door to an office connected to the conference room, turned on the light, and left us alone.

We both knelt down and joined hands, and Julia offered her prayer for wisdom and blessings in making decisions. I added to that a prayer that the directions we took would be guided for our own benefit and for all involved.

"I feel like we can sign this," Julia's face showed mixed trepidation and confidence.

"I feel similarly impressed."

Julia's expression cleared, and we shared a hug.

After we returned to the conference room and had both signed the agreement, Julia and I unpacked our computers and set them up.

While we did so, the door opened, and Ms. Steward showed Mike, Bob, and Jennifer in.

Mike looked at us a bit uncertainly. "We signed," he said, more as a question than a statement. "The internship seemed too good to pass up."

[Backed up at]

Monday, August 17, 2020

PHR: Pink Heels and Rusty -- Title Page and Table of Contents

Pink Heels and Rusty

by Joel Matthew Rees,
Amagasaki, Japan, October 2017
Copyright 2017, 2020 Joel Matthew Rees. 
All rights reserved.

Cheryl is new in town, the only daughter of a systems researcher and an IT professional, a competition swimmer from her previous high school, and a hacker -- and owner of a pair of pink stilettos.

Rusty is the son of the owner of the local independent network service, a hardworking network engineer in training, an avid swimmer, and a white-hat hacker.

Their story is a little geekly romance -- a coming-of-age adventure in the modern world.

  1. Paperboy
  2. UDP Packets
  3. Invitation
  4. Swimmingly
  5. Deeper Water
  6. The New School

Author's note (17 August 2020):

This is derived from a pseudo-flash fiction piece I wrote from a writing prompt that Jenny Flake Rabe posted in the LDS Beta Readers group on Facebook (

I started writing the rest of the story  just before I ran into an open car door on my bicycle, sheering a couple of ribs and shattering my elbow. The accident and the recovery afterwards effectively hid the plot and the world it takes place in from me. (I could read my notes, but I couldn't immerse myself in them deeply enough to continue.)

Truth be told, I'm looking back at my edits, and the edits were going the wrong direction even before the accident. Too much listening to other people, perhaps. It might be interesting to set those up as separate branches of evolution, if I have the time some day.

But other things take priority now, for reasons I don't have time to delineate, but I'm sure can be intuited. I don't know when I might have the spare time, budget, and energy to rebuild the world and the plot and finish it, but I decided to put the chapters I had up in my novels blog anyway.

The first chapter, I'm going to do a clean edit on, since I sort of promised someone I'd give them a first page of something for them to try editing, but everything I write is too non-conventional. The first chapter of this one is at least close to conventional.

If you think this story is interesting, leave me a note. If enough people like it, I'll see if I can shift some things around and resurrect the whole thing, but no promises.

The Missionary and the Enchanted Princess, a Frog Story

(Yeah, I know this is an old bad joke , and I know you're not supposed to take jokes too far. But this is how I'd see this st...