3 ms·
But all of these use a bit shift instead of the (I)DIV instruction. I wasn't saying compilers can't be stupid, but the AI-generated comment explicitly stated th
by rep_lodsb 4y ago
But all of these use a bit shift instead of the (I)DIV instruction. I wasn't saying compilers can't be stupid, but the AI-generated comment explicitly stated that the shift operation was more efficient than division, not that it would result in fewer instructions emitted.
midpoint_rep_lodsb_handwritten:
endbr64
movq $0x8000000000000000, %rax
xorq %rax, %rsi ;convert two's complement to biased
xorq %rax, %rdi
addq %rsi, %rdi
rcrq $1, %rdi
xorq %rdi, %rax ;convert back
ret
(sorry if I got the syntax wrong, AT&T is just horrible)