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While the 68000's registers are 32-bit, the data bus is 16 bit, the A1000, A2000 and A500 that defined the range had 16-bit fetching chipsets, they literally ha

While the 68000's registers are 32-bit, the data bus is 16 bit, the A1000, A2000 and A500 that defined the range had 16-bit fetching chipsets, they literally had 24-bit address buses. None of this says "32-bit". It can't be overlooked. Many games crashed on the 32-bit clean A3000, A1200, A600, A4000 because programmers used the upper byte of addresses for their IQ or whatever. (Similar issues with ARM2 to ARM3 in Acorns, even RISC OS itself can be categorized into '26-bit' and '32-bit clean' varieties due to Acorn thinking the memory space ignores the upper 6 bits so they can store what they like there) The competition before the Amiga's launch solidly called itself "8-bit". The next generation called itself "16-bit" to hype itself. Later machines touted their "32-bit"ness, and then came the Nintendo 64 and PSX on MIPS processors... All the hedges you made, "don't look here, look there" can be reversed to emphasize the 16-bitness! Does this say something about you? Did you come to the Amiga later in its life, e.g. 1991-1993, when 68020s/030s/040s were an option? Or were you there in 1985 when it debuted?

icedchai 6mo ago
I can see it both ways. I remember the Amiga always being compared to other "16-bit" machines, like the Apple IIgs, Atari ST, and early Macs. I also remember the 68000 being referred to as 16/32-bit. Still, from a programmer perspective, the 68000 looked like a 32-bit machine, similar to what Intel did with the 386DX and SX.
kstrauser 6mo ago
The Opteron had a 32 bit HyperTransport bus. Modern CPUs only implement 48 address lines. And yet we’d call all of those 64 bit systems. We wouldn’t call them 32 bit systems, and surely not 48 bit. The 68k’s ISA is 32 bit through and through, however the underlying implementation looks. It did since I bought my A1000, marketed as a 32 bit system, in 1985.
- vidarh 6mo ago
  > marketed as a 32 bit system, in 1985. I'm sure there must have been some, but most of Commodore's early Amiga ads didn't mention the number of bits at all, and from looking through old magazines it doesn't seem most vendors did either.
  - kjs3 6mo ago
    So marketing is how we define ISA architectures. Hmmm...not how I learned it,
LocalH 6mo ago
Is the IBM 5150 PC 8-bit or 16-bit?
- kjs3 6mo ago
  Or 20 bits (address bus width).
kjs3 6mo ago
This is the classic vintage computing pissing contest...it's been argued by geniuses and cretins and it's hubris to think you have the One True Answer. The Z80 is a 4-bit processor (it's ALU is double pumped and 4-bits wide), right? So is the MasPar super (not 32-bits). Obviously, the 8088, mc68008 and ns32008 are 8-bits (size of data bus). And the i386SX is 16-bit. Oh, wait...the 8088 and 68008 are 20-bit processors (address bus width). Unless it's the PLCC version of the 68008, which is a 22-bit processors. IBM 360/20? 16-bit ALU, so there you go. Connection Machines? 1-bit (they're bit-serial) just like the Bendix a couple of generations earlier. While the 68000's registers are 32-bit, the data bus is 16 bit, the A1000, A2000 and A500 that defined the range had 16-bit fetching chipsets, they literally had 24-bit address buses. None of this says "32-bit". It can't be overlooked. Oh, please...you're the one overlooking things and marketing isn't a very good source for architectural definitions. It makes a shitload more sense to say "it's a 32-bit processor because the registers are 32bit" that it does to say "well...the 68000 and 68010 are 24-bit, the 68008 is 20 bits unless its a 68008FN where it's 22-bits, and the 68012 is 30-bits, and the everything else is 32-bits, even tho the fundamental unit of computation since the original spin is 32-bits". There isn't one canonical answer.

icedchai 6mo ago

I can see it both ways. I remember the Amiga always being compared to other "16-bit" machines, like the Apple IIgs, Atari ST, and early Macs. I also remember the 68000 being referred to as 16/32-bit. Still, from a programmer perspective, the 68000 looked like a 32-bit machine, similar to what Intel did with the 386DX and SX.

kstrauser 6mo ago

The Opteron had a 32 bit HyperTransport bus. Modern CPUs only implement 48 address lines. And yet we’d call all of those 64 bit systems. We wouldn’t call them 32 bit systems, and surely not 48 bit. The 68k’s ISA is 32 bit through and through, however the underlying implementation looks. It did since I bought my A1000, marketed as a 32 bit system, in 1985.

vidarh 6mo ago
> marketed as a 32 bit system, in 1985. I'm sure there must have been some, but most of Commodore's early Amiga ads didn't mention the number of bits at all, and from looking through old magazines it doesn't seem most vendors did either.
- kjs3 6mo ago
  So marketing is how we define ISA architectures. Hmmm...not how I learned it,

LocalH 6mo ago

Is the IBM 5150 PC 8-bit or 16-bit?

kjs3 6mo ago
Or 20 bits (address bus width).

kjs3 6mo ago

This is the classic vintage computing pissing contest...it's been argued by geniuses and cretins and it's hubris to think you have the One True Answer. The Z80 is a 4-bit processor (it's ALU is double pumped and 4-bits wide), right? So is the MasPar super (not 32-bits). Obviously, the 8088, mc68008 and ns32008 are 8-bits (size of data bus). And the i386SX is 16-bit. Oh, wait...the 8088 and 68008 are 20-bit processors (address bus width). Unless it's the PLCC version of the 68008, which is a 22-bit processors. IBM 360/20? 16-bit ALU, so there you go. Connection Machines? 1-bit (they're bit-serial) just like the Bendix a couple of generations earlier. While the 68000's registers are 32-bit, the data bus is 16 bit, the A1000, A2000 and A500 that defined the range had 16-bit fetching chipsets, they literally had 24-bit address buses. None of this says "32-bit". It can't be overlooked. Oh, please...you're the one overlooking things and marketing isn't a very good source for architectural definitions. It makes a shitload more sense to say "it's a 32-bit processor because the registers are 32bit" that it does to say "well...the 68000 and 68010 are 24-bit, the 68008 is 20 bits unless its a 68008FN where it's 22-bits, and the 68012 is 30-bits, and the everything else is 32-bits, even tho the fundamental unit of computation since the original spin is 32-bits". There isn't one canonical answer.