6802 with OS/9 Contract

[Platypus]

Last time I used it was on a Tandy. One of you Mac boys perhaps?

I thought the Tandy was a Zilog Z80 processor?

MAC boys no, but Apple II boys I think.

I programmed 6502 on a Commodore Pet

[Diver]

http://en.wikipedia.org/wiki/TRS-80_Color_Computer


Apple I stand corrected

[NickFitz]

I thought the Tandy was a Zilog Z80 processor?

MAC boys no, but Apple II boys I think.

I programmed 6502 on a Commodore Pet

The Apple II (and, indeed, Apple I) had a 6502 processor (which was manufactured by MOS Technology, not Motorola). The original Mac had a 68000, which was from Motorola, and all Macs had 680x0 chips until the PowerPC range was introduced (although Mac OS could still run 680x0 code under automatic emulation right until OS X was introduced - indeed, a friend of mine only got rid of his last Mac OS 9.x machine a couple of years ago, when he'd found a suitable replacement for a font utility he'd been using from his 68030 Mac II onwards).

The Apple III also had a 6502-family processor, although nobody really likes to talk about that one - in fact, when a batch of Apple IIIs were stolen from a warehouse at the time when they were still on sale, the local police chief described the thieves as "dumb"

Z80 was for people who prized high-level processor instructions over computational efficiency. People who can't think down to the level of "these values are asserted on the low-order 8 bits of the address bus and the upper 8 bits of the address bus are ignored during the fetch of the operand... of course, that's why accessing values in page zero saves a clock cycle! "

Having an instruction that meant they didn't have to keep track of the loop index themselves was more important to the Zilog enthusiasts.

In my experience, many of them would crow about "their" processor running at 6 MHz, while 6502s in competing systems "only" ran at 2 Mhz... they didn't even realise that the microcoding of the Z80, compared to the hard-wiring of the 6502, meant that the Z80 had to run at 6 MHz to have the same speed as a 6502 running at 2 MHz - but this also meant that it consumed more power and ran hotter.

There are good reasons why the 6502 was called "the first RISC processor". And there are good reasons why RISC processors didn't win out over CISC processors, the primary reason being that most people who dignify themselves with the term "programmer" are too ignorant of the way a von Neumann architecture processor works to be able to make any adequate use of it.

The triumph of the Intel chip is a triumph of the dumb masses over the truly competent. Still, we're stuck with it now

[NickFitz]

http://en.wikipedia.org/wiki/TRS-80_Color_Computer


Apple I stand corrected

No need to top yourself yet, Diver: the TRS80CC may have had a Zilog chip (as implied by the "80"), but it also ran OS/9 - so that's probably where you used that OS, although the instruction set used by the processor specified for this contract would be somewhat different

[Churchill]

No need to top yourself yet, Diver: the TRS80CC may have had a Zilog chip (as implied by the "80"), but it also ran OS/9 - so that's probably where you used that OS, although the instruction set used by the processor specified for this contract would be somewhat different

Wrong, wrong, wrong.

The Tandy Color(sic) Computer utilised a 6809 derivative.

[NickFitz]

Wrong, wrong, wrong.

The Tandy Color(sic) Computer utilised a 6809 derivative.

DOH!

Of course it did, it was the original Trash 80s that use the Z80

[Churchill]

DOH!

Of course it did, it was the original Trash 80s that use the Z80

Well bugger me! I've out-geeked a geek!

The Z80(x) chips were quite famous for their ability to run CP/M apps so I don't think the TRS/80 was that crap.

In fact there used to be a TRS80 Business Center on Deansgate in Manchester.

[Diver]

I deny all responsibility for hijacking this thread

[VectraMan]

I programmed 6502 on an Oric-1, and then Z80 on a Tatung Einstein.

Having an instruction that meant they didn't have to keep track of the loop index themselves was more important to the Zilog enthusiasts.

I assume you mean "LOOP", but I didn't think that was in z80. I can't say I've ever used it in x86 either, nothing wrong with dec and a jump not zero.

I went to an Intel developer conference once where they told us to only use the "RISC" instruction as they were much more optimised, and the more sophisticated CISC instructions were only included for backwards compatibility. And implementing a complex instruction yourself with the RISC instructions was much better, even if it meant 10 instructions instead of one.

I guess to some extent Intel were victims of their own success: they couldn't release something clean and simple because they had to make the chips backwards compatible.

I wonder if assembler skills will ever become fashionable again.

[Churchill]

I programmed 6502 on an Oric-1, and then Z80 on a Tatung Einstein.



I assume you mean "LOOP", but I didn't think that was in z80. I can't say I've ever used it in x86 either, nothing wrong with dec and a jump not zero.

I went to an Intel developer conference once where they told us to only use the "RISC" instruction as they were much more optimised, and the more sophisticated CISC instructions were only included for backwards compatibility. And implementing a complex instruction yourself with the RISC instructions was much better, even if it meant 10 instructions instead of one.

I guess to some extent Intel were victims of their own success: they couldn't release something clean and simple because they had to make the chips backwards compatible.

I wonder if assembler skills will ever become fashionable again.

The've always been fashionable. You just forgot where to look.

With regards to the RISC vs CISC debate, just look at the money ARM has made...