39 votes
Accepted

What is happening in this algorithm scaling an 8-bit 0-99 value to full-range 16-bit?

Technically, this is just scaling, as quantization means a completely different process. That's simply a multiplication, done with an algorithm which exploits the range of used numbers and avoids the ...
Justme's user avatar
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35 votes
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How common was programming in C targeting 8-bit processors in 1983?

How often was C used to program firmware for 8-bit processors in the early 80s? It would have been a rather unusual choice in 1983. True, C was slowly creeping in, but only on 'big' machines and 16 ...
Raffzahn's user avatar
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18 votes

Is there a common name for this 'switch' like 6800 assembly routine?

The term that comes to mind is "dispatch table". This is a table containing pointers to functions, one of which will be chosen based on an index that has been provided or gets calculated. ...
Walter Mitty's user avatar
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15 votes

What is happening in this algorithm scaling an 8-bit 0-99 value to full-range 16-bit?

The algorithm is called "multiplication". The code appears to compute A×2×165×2, which simplifies to A×660. This linearly maps the range 0–99 into 0–65,340. I don't know the 6303, but ...
pndc's user avatar
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14 votes

How common was programming in C targeting 8-bit processors in 1983?

I was programming full-time on Aztec-C (for Z-80s) starting in mid to late 1982. Our target systems were embedded devices using STD-Bus. We used CP/M as a dev environment. The company also had ...
Flydog57's user avatar
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12 votes

What is happening in this algorithm scaling an 8-bit 0-99 value to full-range 16-bit?

If you look at what's happening step for step, you can see where the 165 is coming from: A is multiplied by 2 (ASLA) A*2 is now multipled by "magic" value 165 (LDAB #165, MUL) Result (HI ...
Retrograde's user avatar
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8 votes

Is there a common name for this 'switch' like 6800 assembly routine?

Is there a common name for this 'switch' like 6800 assembly routine? No. There is no specific name for exactly this technique. In fact, even generic names vary depending on whom to ask. I do need to ...
Raffzahn's user avatar
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7 votes

How common was programming in C targeting 8-bit processors in 1983?

Full C compilers on the 8-bit series was not widely seen, but "mini-C" and "tiny-C" compilers were fairly common. One example is the OSS tiny-C for the Atari machines or Abacus on ...
Maury Markowitz's user avatar
4 votes

Any recommendations for a Hitachi HD6303 assembler?

There's also asl assembler that supports a hell large set of CPUs. The author also supports it (last release dated, at the time of writing this, 2022.02.02), yet without all that fancy github stuff.
lvd's user avatar
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4 votes
Accepted

Any recommendations for a Hitachi HD6303 assembler?

DASM appears to be supported and current (recent release Nov '21), if you have specific issues with specific instructions, you could probably raise them with the maintainer and they'll likely fix them....
Will Hartung's user avatar
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3 votes

How common was programming in C targeting 8-bit processors in 1983?

The Hitachi 6303 is unlike typical 8-bit CPUs of the era, and is in fact suitable for high level language programming and C in particular. It has a stack that can hold local variables. Subroutines ...
JDługosz's user avatar
  • 370
2 votes

How common was programming in C targeting 8-bit processors in 1983?

A quoted comment (by lloyd 2019-02-05 12:54 UTC) from an interesting article about the 6303, MC3 - A DIY 8-bit computer (emphasis is mine): I used those same '80s processors a lot and still find much ...
Greenonline's user avatar
  • 4,356
2 votes

How common was programming in C targeting 8-bit processors in 1983?

I worked in 1984-86 on CAD software for 6502 machines. We did our coding, assembling and linking on CP/M, and wrote a few utilities in C for the CP/M side during 1984. It was probably Aztec C, and ...
John Dallman's user avatar
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2 votes

How common was programming in C targeting 8-bit processors in 1983?

A personal anecdote: My first computer book in 1981 was called "Programming the Z80". It was focussed on assembly. I had learned Fortran in school but the main language for my home computer ...
Bruce J's user avatar
  • 21
2 votes

Can anyone help me identify what 6803/6303 development tools might have been used to build this program?

I think you may be misunderstanding the differing levels at which these things exist. A symbol table for an assembler (the "assembler" level) would not usually make its way into the code in ...
paxdiablo's user avatar
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1 vote

How common was programming in C targeting 8-bit processors in 1983?

I started programming 1984 on a Sinclair (Farewell, Sir Clive!) ZX Spectrum, (which was invented two yeas earlier). Around 1983 was the start of the golden era of 8-bit "home computers" like ...
hvb's user avatar
  • 119

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