ref: dd6ee11d1b147cb98fc1735da3a1573099392f05
dir: /sys/src/libmp/amd64/mpdigdiv.s/
TEXT mpdigdiv(SB),$0 /* MOVL dividend+0(FP),BX */ MOVL 0(RARG),AX MOVL 4(RARG),DX MOVL divisor+8(FP),BX MOVQ quotient+16(FP),DI XORL CX,CX CMPL DX,BX /* dividend >= 2^32 * divisor */ JHS _divovfl CMPL BX,CX /* divisor == 0 */ JE _divovfl DIVL BX /* AX = DX:AX/BX */ MOVL AX,0(DI) RET /* return all 1's */ _divovfl: NOTL CX MOVL CX,0(DI) RET