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Diffstat (limited to 'src/internal/bytealg/equal_arm.s')
| -rw-r--r-- | src/internal/bytealg/equal_arm.s | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/src/internal/bytealg/equal_arm.s b/src/internal/bytealg/equal_arm.s new file mode 100644 index 0000000..a6c4369 --- /dev/null +++ b/src/internal/bytealg/equal_arm.s @@ -0,0 +1,91 @@ +// Copyright 2018 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +#include "go_asm.h" +#include "textflag.h" + +// memequal(a, b unsafe.Pointer, size uintptr) bool +TEXT runtime·memequal(SB),NOSPLIT|NOFRAME,$0-13 + MOVW a+0(FP), R0 + MOVW b+4(FP), R2 + 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: + MOVW $1, R0 + MOVB R0, ret+12(FP) + RET + +// memequal_varlen(a, b unsafe.Pointer) bool +TEXT runtime·memequal_varlen(SB),NOSPLIT|NOFRAME,$0-9 + MOVW a+0(FP), R0 + MOVW b+4(FP), R2 + CMP R0, R2 + B.EQ eq + 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: + MOVW $1, R0 + MOVB R0, ret+8(FP) + RET + +// Input: +// R0: data of a +// 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 + 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.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 |