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cahirwpz/m68k-absl.c

Created April 25, 2016 07:16
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m68k GCC assembly inline for abs function without jump instruction
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m68k-absl.c
static inline int absl(int x) {
int t;
asm("move.l %0,%1\n\t"
"add.l %1,%1\n\t"
"subx.l %1,%1\n\t"
"eor.l %1,%0\n\t"
"sub.l %1,%0\n\t"
: "+r" (x), "=r" (t));
return x;
}
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cahirwpz commented Apr 25, 2016 •
edited

Should be exactly five cycles on M68060, however simplier version with asr.l will take two cycles. On M68000 version with jump will be slightly faster, so again - this trick is not very useful :(

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