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  • Z80 vs 8088 speed

    From Nils M Holm@nmh@sraddha.invalid to comp.os.cpm on Sun Nov 12 17:26:09 2023
    From Newsgroup: comp.os.cpm


    Just compiled my T3X/0 compiler on an 8088 @ 4.77 MHz under DOS
    and was surprised to see that it takes only slightly less time
    than on an Z80 @ 4MHz under CP/M. See http://t3x.org/t3x/t3x0.html

    I would have guessed that the 8088 is much faster at about
    the same clock speed, because it has more 16-bit operations
    and does multiplication and division in hardware. Of course
    the compiler back ends also play a role, but the Z80 backend
    typically emits *more* instructions for the same program.

    I have never used an 8088 back in the days. In case you have,
    what was your experience? Any technical explanation for my
    results?
    --
    Nils M Holm < n m h @ t 3 x . o r g > http://t3x.org
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  • From drb@drb@ihatespam.msu.edu (Dennis Boone) to comp.os.cpm on Sun Nov 12 19:23:08 2023
    From Newsgroup: comp.os.cpm

    I would have guessed that the 8088 is much faster at about
    the same clock speed, because it has more 16-bit operations
    and does multiplication and division in hardware. Of course
    the compiler back ends also play a role, but the Z80 backend
    typically emits *more* instructions for the same program.

    The 8088 gives up a substantial portion of any 16-bit advantage to its
    8-bit external bus.

    De
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  • From Zbig@zbigniew2011@gmail.com to comp.os.cpm on Sat Nov 18 04:25:49 2023
    From Newsgroup: comp.os.cpm

    The 8088 gives up a substantial portion of any 16-bit advantage to its
    8-bit external bus.

    Not just that: https://trixter.oldskool.org/2011/06/04/at-a-disadvantage/

    Quick, without doing any research: What early 1980s computer was faster,
    the IBM PC or the Commodore 64? The IBM PC ran an 8088 at nearly 5MHz,
    whereas the C64 ran a 6502 variant at 1MHz. The PC cost thousands of dollars, the C64 hundreds. The PC had a 1 megabyte address space; the C64 only 64K.
    Is this a trick question?

    It is! The C64 was faster. [..]
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  • From Nils M Holm@nmh@sraddha.invalid to comp.os.cpm on Sun Nov 19 11:41:47 2023
    From Newsgroup: comp.os.cpm

    Zbig <zbigniew2011@gmail.com> wrote:
    The 8088 gives up a substantial portion of any 16-bit advantage to its
    8-bit external bus.

    Not just that: https://trixter.oldskool.org/2011/06/04/at-a-disadvantage/

    Quick, without doing any research: What early 1980s computer was faster,
    the IBM PC or the Commodore 64? The IBM PC ran an 8088 at nearly 5MHz, whereas the C64 ran a 6502 variant at 1MHz. The PC cost thousands of dollars, the C64 hundreds. The PC had a 1 megabyte address space; the C64 only 64K.
    Is this a trick question?

    It is! The C64 was faster. [..]

    Interesting! So the real surprise is that the 8088 at about the same
    clock speed is almost as fast as the Z80.
    --
    Nils M Holm < n m h @ t 3 x . o r g > http://t3x.org
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