blob: c5bfdda33fb027fa16ada91e3b8aff7f04b82fdc [file] [log] [blame]
// 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"
TEXT ·Compare(SB),NOSPLIT|NOFRAME,$0-28
MOVW a_base+0(FP), R2
MOVW a_len+4(FP), R0
MOVW b_base+12(FP), R3
MOVW b_len+16(FP), R1
ADD $28, R13, R7
B cmpbody<>(SB)
TEXT runtime·cmpstring(SB),NOSPLIT|NOFRAME,$0-20
MOVW a_base+0(FP), R2
MOVW a_len+4(FP), R0
MOVW b_base+8(FP), R3
MOVW b_len+12(FP), R1
ADD $20, R13, R7
B cmpbody<>(SB)
// On entry:
// R0 is the length of a
// R1 is the length of b
// R2 points to the start of a
// R3 points to the start of b
// R7 points to return value (-1/0/1 will be written here)
//
// On exit:
// R4, R5, and R6 are clobbered
TEXT cmpbody<>(SB),NOSPLIT|NOFRAME,$0-0
CMP R2, R3
BEQ samebytes
CMP R0, R1
MOVW R0, R6
MOVW.LT R1, R6 // R6 is min(R0, R1)
ADD R2, R6 // R2 is current byte in a, R6 is last byte in a to compare
loop:
CMP R2, R6
BEQ samebytes // all compared bytes were the same; compare lengths
MOVBU.P 1(R2), R4
MOVBU.P 1(R3), R5
CMP R4, R5
BEQ loop
// bytes differed
MOVW.LT $1, R0
MOVW.GT $-1, R0
MOVW R0, (R7)
RET
samebytes:
CMP R0, R1
MOVW.LT $1, R0
MOVW.GT $-1, R0
MOVW.EQ $0, R0
MOVW R0, (R7)
RET