diff options
Diffstat (limited to 'src/internal/bytealg')
| -rw-r--r-- | src/internal/bytealg/equal_arm.s | 57 |
1 files changed, 48 insertions, 9 deletions
diff --git a/src/internal/bytealg/equal_arm.s b/src/internal/bytealg/equal_arm.s index d829f2bcdc..b8f2b69bbe 100644 --- a/src/internal/bytealg/equal_arm.s +++ b/src/internal/bytealg/equal_arm.s @@ -8,14 +8,19 @@ TEXT ·Equal(SB),NOSPLIT,$0-25 MOVW a_len+4(FP), R1 MOVW b_len+16(FP), R3 - CMP R1, R3 // unequal lengths are not equal B.NE notequal + CMP $0, R1 // short path to handle 0-byte case + B.EQ equal MOVW a_base+0(FP), R0 MOVW b_base+12(FP), R2 MOVW $ret+24(FP), R7 B memeqbody<>(SB) +equal: + MOVW $1, R0 + MOVB R0, ret+24(FP) + RET notequal: MOVW $0, R0 MOVBU R0, ret+24(FP) @@ -28,6 +33,8 @@ TEXT runtime·memequal(SB),NOSPLIT|NOFRAME,$0-13 CMP R0, R2 B.EQ eq MOVW size+8(FP), R1 + CMP $0, R1 + B.EQ eq // short path to handle 0-byte case MOVW $ret+12(FP), R7 B memeqbody<>(SB) eq: @@ -41,7 +48,9 @@ TEXT runtime·memequal_varlen(SB),NOSPLIT|NOFRAME,$0-9 MOVW b+4(FP), R2 CMP R0, R2 B.EQ eq - MOVW 4(R7), R1 // compiler stores size at offset 4 in the closure + MOVW 4(R7), R1 // compiler stores size at offset 4 in the closure + CMP $0, R1 + B.EQ eq // short path to handle 0-byte case MOVW $ret+8(FP), R7 B memeqbody<>(SB) eq: @@ -54,20 +63,50 @@ eq: // R1: length // R2: data of b // R7: points to return value +// +// On exit: +// R4, R5 and R6 are clobbered TEXT memeqbody<>(SB),NOSPLIT|NOFRAME,$0-0 - ADD R0, R1 // end -loop: + CMP $1, R1 + B.EQ one // 1-byte special case for better performance + + CMP $4, R1 + ADD R0, R1 // R1 is the end of the range to compare + B.LT byte_loop // length < 4 + AND $3, R0, R6 + CMP $0, R6 + B.NE byte_loop // unaligned a, use byte-wise compare (TODO: try to align a) + AND $3, R2, R6 + CMP $0, R6 + B.NE byte_loop // unaligned b, use byte-wise compare + AND $0xfffffffc, R1, R6 + // length >= 4 +chunk4_loop: + MOVW.P 4(R0), R4 + MOVW.P 4(R2), R5 + CMP R4, R5 + B.NE notequal + CMP R0, R6 + B.NE chunk4_loop CMP R0, R1 B.EQ equal // reached the end +byte_loop: MOVBU.P 1(R0), R4 MOVBU.P 1(R2), R5 CMP R4, R5 - B.EQ loop -notequal: - MOVW $0, R0 - MOVB R0, (R7) - RET + B.NE notequal + CMP R0, R1 + B.NE byte_loop equal: MOVW $1, R0 MOVB R0, (R7) RET +one: + MOVBU (R0), R4 + MOVBU (R2), R5 + CMP R4, R5 + B.EQ equal +notequal: + MOVW $0, R0 + MOVB R0, (R7) + RET |