// 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.
//go:build mips64 || mips64le
#include "go_asm.h"
#include "textflag.h"
TEXT ·Compare(SB),NOSPLIT,$0-56
MOVV a_base+0(FP), R3
MOVV b_base+24(FP), R4
MOVV a_len+8(FP), R1
MOVV b_len+32(FP), R2
MOVV $ret+48(FP), R9
JMP cmpbody<>(SB)
TEXT runtime·cmpstring(SB),NOSPLIT,$0-40
MOVV a_base+0(FP), R3
MOVV b_base+16(FP), R4
MOVV a_len+8(FP), R1
MOVV b_len+24(FP), R2
MOVV $ret+32(FP), R9
JMP cmpbody<>(SB)
// On entry:
// R1 length of a
// R2 length of b
// R3 points to the start of a
// R4 points to the start of b
// R9 points to the return value (-1/0/1)
TEXT cmpbody<>(SB),NOSPLIT|NOFRAME,$0
BEQ R3, R4, samebytes // same start of a and b
SGTU R1, R2, R7
BNE R0, R7, r2_lt_r1
MOVV R1, R10
JMP entry
r2_lt_r1:
MOVV R2, R10 // R10 is min(R1, R2)
entry:
ADDV R3, R10, R8 // R3 start of a, R8 end of a
BEQ R3, R8, samebytes // length is 0
SRLV $4, R10 // R10 is number of chunks
BEQ R0, R10, byte_loop
// make sure both a and b are aligned.
OR R3, R4, R11
AND $7, R11
BNE R0, R11, byte_loop
chunk16_loop:
BEQ R0, R10, byte_loop
MOVV (R3), R6
MOVV (R4), R7
BNE R6, R7, byte_loop
MOVV 8(R3), R13
MOVV 8(R4), R14
ADDV $16, R3
ADDV $16, R4
SUBVU $1, R10
BEQ R13, R14, chunk16_loop
SUBV $8, R3
SUBV $8, R4
byte_loop:
BEQ R3, R8, samebytes
MOVBU (R3), R6
ADDVU $1, R3
MOVBU (R4), R7
ADDVU $1, R4
BEQ R6, R7, byte_loop
byte_cmp:
SGTU R6, R7, R8 // R8 = 1 if (R6 > R7)
BNE R0, R8, ret
MOVV $-1, R8
JMP ret
samebytes:
SGTU R1, R2, R6
SGTU R2, R1, R7
SUBV R7, R6, R8
ret:
MOVV R8, (R9)
RET
