ref: 15b2a406cc0e11377cee12b5a112c003f7250a7f
dir: /libmp/Plan9-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