ref: 909323e92a4e694bff5908e500d8655ac1bbd932
dir: /sys/src/libc/68000/muldivrt.s/
/* * calls _divul with * absolute value arguments */ TEXT _divsl(SB), $0 MOVL R0, TOS MOVL b+4(FP), R0 BPL y1 NEGL R0 MOVL R0, TOS MOVL a+0(FP), R0 BPL y3 NEGL R0 MOVL R0, TOS /* neg/neg */ JSR _divul(SB) MOVL TOS, R0 MOVL R0, a+0(FP) MOVL TOS, R0 NEGL R0 MOVL R0, b+4(FP) MOVL TOS, R0 RTS y1: MOVL R0, TOS MOVL a+0(FP), R0 BPL y2 NEGL R0 MOVL R0, TOS /* neg/pos */ JSR _divul(SB) MOVL TOS, R0 NEGL R0 MOVL R0, a+0(FP) MOVL TOS, R0 NEGL R0 MOVL R0, b+4(FP) MOVL TOS, R0 RTS y2: MOVL R0, TOS /* pos/pos */ JSR _divul(SB) MOVL TOS, R0 MOVL R0, a+0(FP) MOVL TOS, R0 MOVL R0, b+4(FP) MOVL TOS, R0 RTS y3: MOVL R0, TOS /* pos/neg */ JSR _divul(SB) MOVL TOS, R0 NEGL R0 MOVL R0, a+0(FP) MOVL TOS, R0 MOVL R0, b+4(FP) MOVL TOS, R0 RTS /* * for(i=1;; i++) { * if(den & (1<<31)) * break; * den <<= 1; * } * * for(; i; i--) { * quo <<= 1; * if(num >= den) { * num -= den; * quo |= 1; * } * den >>= 1; * } */ TEXT _divul(SB), $0 MOVL R0, TOS /* i */ MOVL R1, TOS /* num */ MOVL R2, TOS /* den */ MOVL R3, TOS /* quo */ MOVL $0, R0 MOVL $0, R3 MOVL a+0(FP), R1 MOVL b+4(FP), R2 BEQ xout BMI x1 ADDL $1, R0 LSLL $1, R2 BPL -2(PC) x1: LSLL $1, R3 CMPL R1, R2 BCS 3(PC) SUBL R2, R1 ORL $1, R3 LSRL $1, R2 DBMI R0, x1 MOVL R3, a+0(FP) MOVL R1, b+4(FP) xout: MOVL TOS, R3 MOVL TOS, R2 MOVL TOS, R1 MOVL TOS, R0 RTS /* * x = 0; * for(i=0; i<32; i++) { * if(a & 1) * x += b; * a >>= 1; * b <<= 1; * } * a = x; */ TEXT _mull(SB), $0 MOVL R0, TOS /* i */ MOVL R1, TOS /* a */ MOVL R2, TOS /* b */ MOVL R3, TOS /* x */ MOVL a+0(FP), R1 MOVL b+4(FP), R2 MOVL $32, R0 CLRL R3 z1: ROTRL $1, R1 BCC 2(PC) ADDL R2, R3 LSLL $1, R2 DBEQ R0, z1 MOVL R3, b+4(FP) MOVL TOS, R3 MOVL TOS, R2 MOVL TOS, R1 MOVL TOS, R0 RTS TEXT _ccr(SB), $0 PEA (A0) SUBL A0, A0 BCC 2(PC) LEA 1(A0), A0 BVC 2(PC) LEA 2(A0), A0 BNE 2(PC) LEA 4(A0), A0 BPL 2(PC) LEA 8(A0), A0 MOVW A0, a+0(FP) MOVL TOS, A0 RTS