ref: ae1cfc9082b3f56a8502938b892bf0555110a741
dir: /sys/src/libc/arm/strcmp.s/
TEXT strcmp(SB), $0 MOVW R0, R1 MOVW s2+4(FP), R2 MOVW $0xFF, R3 /* mask */ _align: /* align s1 on 4 */ TST $3, R1 BEQ _aligned MOVBU.P 1(R1), R4 /* implicit write back */ MOVBU.P 1(R2), R8 /* implicit write back */ SUB.S R8, R4, R0 BNE _return CMP $0, R4 BEQ _return B _align _aligned: /* is s2 now aligned? */ TST $3, R2 BNE _unaligned _aloop: MOVW.P 4(R1), R5 /* 4 at a time */ MOVW.P 4(R2), R7 AND R5, R3, R4 AND R7, R3, R8 SUB.S R8, R4, R0 BNE _return CMP $0, R4 BEQ _return AND R5>>8, R3, R4 AND R7>>8, R3, R8 SUB.S R8, R4, R0 BNE _return CMP $0, R4 BEQ _return AND R5>>16, R3, R4 AND R7>>16, R3, R8 SUB.S R8, R4, R0 BNE _return CMP $0, R4 BEQ _return AND R5>>24, R3, R4 AND R7>>24, R3, R8 SUB.S R8, R4, R0 BNE _return CMP $0, R4 BEQ _return B _aloop _return: RET _unaligned: MOVBU.P 1(R1), R4 /* implicit write back */ MOVBU.P 1(R2), R8 /* implicit write back */ SUB.S R8, R4, R0 BNE _return CMP $0, R4 BEQ _return B _unaligned