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-rw-r--r--src/internal/bytealg/compare_mips64x.s89
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diff --git a/src/internal/bytealg/compare_mips64x.s b/src/internal/bytealg/compare_mips64x.s
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+// 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
+// +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