// Copyright 2019 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"
#define CTXT S10
// func memequal_varlen(a, b unsafe.Pointer) bool
TEXT runtime·memequal_varlen<ABIInternal>(SB),NOSPLIT|NOFRAME,$0-17
// X10 = a_base
// X11 = b_base
MOV 8(CTXT), X12 // compiler stores size at offset 8 in the closure
JMP runtime·memequal<ABIInternal>(SB)
// func memequal(a, b unsafe.Pointer, size uintptr) bool
TEXT runtime·memequal<ABIInternal>(SB),NOSPLIT|NOFRAME,$0-25
// X10 = a_base
// X11 = b_base
// X12 = size
BNE X10, X11, length_check
MOV $0, X12
length_check:
BEQZ X12, done
MOV $32, X23
BLT X12, X23, loop4_check
// Check alignment - if alignment differs we have to do one byte at a time.
AND $7, X10, X9
AND $7, X11, X19
BNE X9, X19, loop4_check
BEQZ X9, loop32_check
// Check one byte at a time until we reach 8 byte alignment.
SUB X9, X0, X9
ADD $8, X9, X9
SUB X9, X12, X12
align:
SUB $1, X9
MOVBU 0(X10), X19
MOVBU 0(X11), X20
BNE X19, X20, done
ADD $1, X10
ADD $1, X11
BNEZ X9, align
loop32_check:
MOV $32, X9
BLT X12, X9, loop16_check
loop32:
MOV 0(X10), X19
MOV 0(X11), X20
MOV 8(X10), X21
MOV 8(X11), X22
BNE X19, X20, done
BNE X21, X22, done
MOV 16(X10), X14
MOV 16(X11), X15
MOV 24(X10), X16
MOV 24(X11), X17
BNE X14, X15, done
BNE X16, X17, done
ADD $32, X10
ADD $32, X11
SUB $32, X12
BGE X12, X9, loop32
BEQZ X12, done
loop16_check:
MOV $16, X23
BLT X12, X23, loop4_check
loop16:
MOV 0(X10), X19
MOV 0(X11), X20
MOV 8(X10), X21
MOV 8(X11), X22
BNE X19, X20, done
BNE X21, X22, done
ADD $16, X10
ADD $16, X11
SUB $16, X12
BGE X12, X23, loop16
BEQZ X12, done
loop4_check:
MOV $4, X23
BLT X12, X23, loop1
loop4:
MOVBU 0(X10), X19
MOVBU 0(X11), X20
MOVBU 1(X10), X21
MOVBU 1(X11), X22
BNE X19, X20, done
BNE X21, X22, done
MOVBU 2(X10), X14
MOVBU 2(X11), X15
MOVBU 3(X10), X16
MOVBU 3(X11), X17
BNE X14, X15, done
BNE X16, X17, done
ADD $4, X10
ADD $4, X11
SUB $4, X12
BGE X12, X23, loop4
loop1:
BEQZ X12, done
MOVBU 0(X10), X19
MOVBU 0(X11), X20
BNE X19, X20, done
ADD $1, X10
ADD $1, X11
SUB $1, X12
JMP loop1
done:
// If X12 is zero then memory is equivalent.
SEQZ X12, X10
RET
