Two Stop Bits | Love how this chronicles the instruction count at 301 million and then for each ...

bmonkey325 3 days ago | parent

Love how this chronicles the instruction count at 301 million and then for each optimization and compromise it cuts xx million instructions of the runtime.

I think the 6502 final would need to be run in an emulator to get the retired instruction count. On 586+ cpu such a function is baked into the hardware.

Trixter 1 day ago
RDPMC was introduced with the Pentium; was there some other instruction or method you were thinking of for 386 or 486 CPUs?
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- bmonkey325 20 hours ago
  Good catch. Those were only in p5 and p6+ I was watching baseball in the easy chair when I wrote that. Fixed.
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colinlm 2 days ago
Thanks :) I do time the 6502 code using the MAME emulator, its debugger's trace feature, and a profiler I made. It's far from perfect (gets very confused by tricks like pha/pha/rts in the IIe ROM) but works under IIc emulation and allows me to precisely count cycles in my code: https://www.colino.net/wordpress/en/a2trace-debug-and-profil.../
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ddingus 2 days ago
Yeah, it was a good optimization effort.
My preference was to work in cycles. Many systems have a timer one can use to get the cycle counts. There isn't one on a stock Apple 2. Many cards have the PIA chip, 6522, which does have two timers, though they are only 16 bit.
Or, a quick hand timing gets fairly close. On that, the only real difficulty is finding a task that scales well with our perceptual slowness.
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