datajerk wrote:
I read a blog post where the blogger said that a 1MHz 6502 was faster than a 4.77 MHz 8088. I wanted to believe him until I read his method. He used the specs and measured the time it would take to fetch, decode, and execute a shift instruction. And if that is all the program was going to do (a *single* shift), then he was right. However if you did a series of shifts the 4.77 MHz 8088 was 2.6x faster than the 1MHz 6502 (when using words not bytes, bytes vs. bytes 8088 was 2x faster).
The point is that one should actually run real code to compare.
The published times for ten iterations of the Sieve benchmark are that a 5MHz 8088 takes 4.0 seconds while a 4MHz (not 1MHz) 6502 (NMOS) takes 3.1 seconds, making it about 60% more cycle-efficient than the 8088. Bill Mensch had 10MHz 6502's in the 1970's, although I think the off-the-shelf ones were limited to 2MHz at that time. (The IBM PC was not out yet.)
Quote:
BTW, are you looking at the 68008 or 68000 timings? The time to write a byte or word is the same for the 68000.
I don't know which one of us you're asking, but I was specifically looking at the 68008 timings since that's what was brought up.
Again of course the way the program is approached is super important-- making a lot more difference than which processor is used, if the processors are anywhere near the same class. The original 4.77MHz IBM PC took about 9
minutes to do a 1024-point complex FFT in GWBASIC. My 1980's handheld battery-powered HP-71 computer with the math module and a 625kHz clock and 4-bit data bus did it with greater precision in half the time (about 4:30), in its far superior BASIC. My 5MHz 6502 workbench computer does an FFT twice that big (2048 points, complex) in 16-bit scaled-integer in Forth in 5
seconds. If I were to implement the
large look up tables, it might be down to a few percent of a second.