github.com/hxx258456/ccgo@v0.0.5-0.20230213014102-48b35f46f66f/internal/bytealg/compare_mips64x.s (about)

     1  // Copyright 2019 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  //go:build mips64 || mips64le
     6  // +build mips64 mips64le
     7  
     8  #include "go_asm.h"
     9  #include "textflag.h"
    10  
    11  TEXT ·Compare(SB),NOSPLIT,$0-56
    12  	MOVV	a_base+0(FP), R3
    13  	MOVV	b_base+24(FP), R4
    14  	MOVV	a_len+8(FP), R1
    15  	MOVV	b_len+32(FP), R2
    16  	MOVV	$ret+48(FP), R9
    17  	JMP	cmpbody<>(SB)
    18  
    19  TEXT runtime·cmpstring(SB),NOSPLIT,$0-40
    20  	MOVV	a_base+0(FP), R3
    21  	MOVV	b_base+16(FP), R4
    22  	MOVV	a_len+8(FP), R1
    23  	MOVV	b_len+24(FP), R2
    24  	MOVV	$ret+32(FP), R9
    25  	JMP	cmpbody<>(SB)
    26  
    27  // On entry:
    28  // R1 length of a
    29  // R2 length of b
    30  // R3 points to the start of a
    31  // R4 points to the start of b
    32  // R9 points to the return value (-1/0/1)
    33  TEXT cmpbody<>(SB),NOSPLIT|NOFRAME,$0
    34  	BEQ	R3, R4, samebytes // same start of a and b
    35  
    36  	SGTU	R1, R2, R7
    37  	BNE	R0, R7, r2_lt_r1
    38  	MOVV	R1, R10
    39  	JMP	entry
    40  r2_lt_r1:
    41  	MOVV	R2, R10	// R10 is min(R1, R2)
    42  entry:
    43  	ADDV	R3, R10, R8	// R3 start of a, R8 end of a
    44  	BEQ	R3, R8, samebytes // length is 0
    45  
    46  	SRLV	$4, R10		// R10 is number of chunks
    47  	BEQ	R0, R10, byte_loop
    48  
    49  	// make sure both a and b are aligned.
    50  	OR	R3, R4, R11
    51  	AND	$7, R11
    52  	BNE	R0, R11, byte_loop
    53  
    54  chunk16_loop:
    55  	BEQ	R0, R10, byte_loop
    56  	MOVV	(R3), R6
    57  	MOVV	(R4), R7
    58  	BNE	R6, R7, byte_loop
    59  	MOVV	8(R3), R13
    60  	MOVV	8(R4), R14
    61  	ADDV	$16, R3
    62  	ADDV	$16, R4
    63  	SUBVU	$1, R10
    64  	BEQ	R13, R14, chunk16_loop
    65  	SUBV	$8, R3
    66  	SUBV	$8, R4
    67  
    68  byte_loop:
    69  	BEQ	R3, R8, samebytes
    70  	MOVBU	(R3), R6
    71  	ADDVU	$1, R3
    72  	MOVBU	(R4), R7
    73  	ADDVU	$1, R4
    74  	BEQ	R6, R7, byte_loop
    75  
    76  byte_cmp:
    77  	SGTU	R6, R7, R8 // R8 = 1 if (R6 > R7)
    78  	BNE	R0, R8, ret
    79  	MOVV	$-1, R8
    80  	JMP	ret
    81  
    82  samebytes:
    83  	SGTU	R1, R2, R6
    84  	SGTU	R2, R1, R7
    85  	SUBV	R7, R6, R8
    86  
    87  ret:
    88  	MOVV	R8, (R9)
    89  	RET