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Thread: Has there ever been 68000-bit processors?

  1. #1

    Default Has there ever been 68000-bit processors?

    I am that old Macs have 68k processors, but there is no such thing as 68000-bit, the current Macs are 64-bit! What am I getting wrong here?

  2. #2
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    The 68k refers to a Motorola part number. 64 bits refers to the native data bus width of the processor.

    The 68000 CPU was a Motorola 16 bit processor with an external 16 bit data bus. The 68008 CPU was a Motorola 16 bit processor with an external 8 bit data bus. Internal logic read two sequential 8 bit data bytes to form a 16 bit word internally.

    A modern iMac contains a 64 bit Intel processor.

    Hope that clears up the confusion?

    Dave

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    Quote Originally Posted by daver2 View Post
    The 68000 CPU was a Motorola 16 bit processor
    is the 68020 a 16 bit processor?

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    Quote Originally Posted by Al Kossow View Post
    is the 68020 a 16 bit processor?
    I'm pretty sure people have come to blows (beer bottles smashed on the bar, the whole enchilada) over whether or not the 68000 should be called a 16 or 32 bit processor, but I think the 32-bit-ness is pretty unequivocal in the case of the 68020.
    My Retro-computing YouTube Channel (updates... eventually?): Paleozoic PCs

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    Yes...

    Is a Zilog Z80 an 8 or 16 bit machine? It has 8 bit registers internally, but they can be ‘joined together’ to form 16 bit register pairs. To further confuse things, you can perform 16-bit arithmetic on some of the register pairs. I would still call the Z80 an 8-bit processor however.

    Churches have been built on less...

    Dave

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    I generally go by the width of the ALU. Not always, however. There are some serial ALU minis and microprocessors; it just wouldn't be right to call them "one bit".

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    Don't forget the 65536-bit CM-1

  8. #8

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    Yes, it does!

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    I read once that the Z80 has a 4 bit ALU so maybe it is a 4 bit processor, maybe this explains why the 6502 is sometimes faster.

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    >>> maybe this explains why the 6502 is sometimes faster.

    Let’s not ignite that flame war shall we !

    Dave

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