github.com/gagliardetto/golang-go@v0.0.0-20201020153340-53909ea70814/not-internal/bytealg/compare_mipsx.s (about)

     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  // +build mips mipsle
     6  
     7  #include "go_asm.h"
     8  #include "textflag.h"
     9  
    10  TEXT ·Compare(SB),NOSPLIT,$0-28
    11  	MOVW	a_base+0(FP), R3
    12  	MOVW	b_base+12(FP), R4
    13  	MOVW	a_len+4(FP), R1
    14  	MOVW	b_len+16(FP), R2
    15  	BEQ	R3, R4, samebytes
    16  	SGTU	R1, R2, R7
    17  	MOVW	R1, R8
    18  	CMOVN	R7, R2, R8	// R8 is min(R1, R2)
    19  
    20  	ADDU	R3, R8	// R3 is current byte in a, R8 is last byte in a to compare
    21  loop:
    22  	BEQ	R3, R8, samebytes
    23  
    24  	MOVBU	(R3), R6
    25  	ADDU	$1, R3
    26  	MOVBU	(R4), R7
    27  	ADDU	$1, R4
    28  	BEQ	R6, R7 , loop
    29  
    30  	SGTU	R6, R7, R8
    31  	MOVW	$-1, R6
    32  	CMOVZ	R8, R6, R8
    33  	JMP	cmp_ret
    34  samebytes:
    35  	SGTU	R1, R2, R6
    36  	SGTU	R2, R1, R7
    37  	SUBU	R7, R6, R8
    38  cmp_ret:
    39  	MOVW	R8, ret+24(FP)
    40  	RET
    41  
    42  TEXT runtime·cmpstring(SB),NOSPLIT,$0-20
    43  	MOVW	a_base+0(FP), R3
    44  	MOVW	a_len+4(FP), R1
    45  	MOVW	b_base+8(FP), R4
    46  	MOVW	b_len+12(FP), R2
    47  	BEQ	R3, R4, samebytes
    48  	SGTU	R1, R2, R7
    49  	MOVW	R1, R8
    50  	CMOVN	R7, R2, R8	// R8 is min(R1, R2)
    51  
    52  	ADDU	R3, R8	// R3 is current byte in a, R8 is last byte in a to compare
    53  loop:
    54  	BEQ	R3, R8, samebytes	// all compared bytes were the same; compare lengths
    55  
    56  	MOVBU	(R3), R6
    57  	ADDU	$1, R3
    58  	MOVBU	(R4), R7
    59  	ADDU	$1, R4
    60  	BEQ	R6, R7 , loop
    61  	// bytes differed
    62  	SGTU	R6, R7, R8
    63  	MOVW	$-1, R6
    64  	CMOVZ	R8, R6, R8
    65  	JMP	cmp_ret
    66  samebytes:
    67  	SGTU	R1, R2, R6
    68  	SGTU	R2, R1, R7
    69  	SUBU	R7, R6, R8
    70  cmp_ret:
    71  	MOVW	R8, ret+16(FP)
    72  	RET