1// Copyright 2018 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5#include "go_asm.h"
6#include "textflag.h"
7
8// memequal(a, b unsafe.Pointer, size uintptr) bool
9TEXT runtime·memequal(SB),NOSPLIT|NOFRAME,$0-13
10 MOVW a+0(FP), R0
11 MOVW b+4(FP), R2
12 CMP R0, R2
13 B.EQ eq
14 MOVW size+8(FP), R1
15 CMP $0, R1
16 B.EQ eq // short path to handle 0-byte case
17 MOVW $ret+12(FP), R7
18 B memeqbody<>(SB)
19eq:
20 MOVW $1, R0
21 MOVB R0, ret+12(FP)
22 RET
23
24// memequal_varlen(a, b unsafe.Pointer) bool
25TEXT runtime·memequal_varlen(SB),NOSPLIT|NOFRAME,$0-9
26 MOVW a+0(FP), R0
27 MOVW b+4(FP), R2
28 CMP R0, R2
29 B.EQ eq
30 MOVW 4(R7), R1 // compiler stores size at offset 4 in the closure
31 CMP $0, R1
32 B.EQ eq // short path to handle 0-byte case
33 MOVW $ret+8(FP), R7
34 B memeqbody<>(SB)
35eq:
36 MOVW $1, R0
37 MOVB R0, ret+8(FP)
38 RET
39
40// Input:
41// R0: data of a
42// R1: length
43// R2: data of b
44// R7: points to return value
45//
46// On exit:
47// R4, R5 and R6 are clobbered
48TEXT memeqbody<>(SB),NOSPLIT|NOFRAME,$0-0
49 CMP $1, R1
50 B.EQ one // 1-byte special case for better performance
51
52 CMP $4, R1
53 ADD R0, R1 // R1 is the end of the range to compare
54 B.LT byte_loop // length < 4
55 AND $3, R0, R6
56 CMP $0, R6
57 B.NE byte_loop // unaligned a, use byte-wise compare (TODO: try to align a)
58 AND $3, R2, R6
59 CMP $0, R6
60 B.NE byte_loop // unaligned b, use byte-wise compare
61 AND $0xfffffffc, R1, R6
62 // length >= 4
63chunk4_loop:
64 MOVW.P 4(R0), R4
65 MOVW.P 4(R2), R5
66 CMP R4, R5
67 B.NE notequal
68 CMP R0, R6
69 B.NE chunk4_loop
70 CMP R0, R1
71 B.EQ equal // reached the end
72byte_loop:
73 MOVBU.P 1(R0), R4
74 MOVBU.P 1(R2), R5
75 CMP R4, R5
76 B.NE notequal
77 CMP R0, R1
78 B.NE byte_loop
79equal:
80 MOVW $1, R0
81 MOVB R0, (R7)
82 RET
83one:
84 MOVBU (R0), R4
85 MOVBU (R2), R5
86 CMP R4, R5
87 B.EQ equal
88notequal:
89 MOVW $0, R0
90 MOVB R0, (R7)
91 RET
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