Text file src/internal/bytealg/compare_loong64.s

     1  // Copyright 2022 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  #include "go_asm.h"
     6  #include "textflag.h"
     7  
     8  TEXT ¬∑Compare<ABIInternal>(SB),NOSPLIT,$0-56
     9  #ifndef GOEXPERIMENT_regabiargs
    10  	MOVV	a_base+0(FP), R4
    11  	MOVV	a_len+8(FP), R5
    12  	MOVV	b_base+24(FP), R6
    13  	MOVV	b_len+32(FP), R7
    14  	MOVV	$ret+48(FP), R13
    15  #else
    16  	// R4 = a_base
    17  	// R5 = a_len
    18  	// R6 = a_cap (unused)
    19  	// R7 = b_base (want in R6)
    20  	// R8 = b_len (want in R7)
    21  	// R9 = b_cap (unused)
    22  	MOVV	R7, R6
    23  	MOVV	R8, R7
    24  #endif
    25  	JMP	cmpbody<>(SB)
    26  
    27  TEXT runtime¬∑cmpstring<ABIInternal>(SB),NOSPLIT,$0-40
    28  #ifndef GOEXPERIMENT_regabiargs
    29  	MOVV	a_base+0(FP), R4
    30  	MOVV	b_base+16(FP), R6
    31  	MOVV	a_len+8(FP), R5
    32  	MOVV	b_len+24(FP), R7
    33  	MOVV	$ret+32(FP), R13
    34  #endif
    35  	// R4 = a_base
    36  	// R5 = a_len
    37  	// R6 = b_base
    38  	// R7 = b_len
    39  	JMP	cmpbody<>(SB)
    40  
    41  // On entry:
    42  // R5 length of a
    43  // R7 length of b
    44  // R4 points to the start of a
    45  // R6 points to the start of b
    46  // R13 points to the return value (-1/0/1)
    47  TEXT cmpbody<>(SB),NOSPLIT|NOFRAME,$0
    48  	BEQ	R4, R6, samebytes // same start of a and b
    49  
    50  	SGTU	R5, R7, R9
    51  	BNE	R0, R9, r2_lt_r1
    52  	MOVV	R5, R14
    53  	JMP	entry
    54  r2_lt_r1:
    55  	MOVV	R7, R14	// R14 is min(R4, R5)
    56  entry:
    57  	ADDV	R4, R14, R12	// R6 start of a, R14 end of a
    58  	BEQ	R4, R12, samebytes // length is 0
    59  
    60  	SRLV	$4, R14		// R14 is number of chunks
    61  	BEQ	R0, R14, byte_loop
    62  
    63  	// make sure both a and b are aligned.
    64  	OR	R4, R6, R15
    65  	AND	$7, R15
    66  	BNE	R0, R15, byte_loop
    67  
    68  	PCALIGN	$16
    69  chunk16_loop:
    70  	BEQ	R0, R14, byte_loop
    71  	MOVV	(R4), R8
    72  	MOVV	(R6), R9
    73  	BNE	R8, R9, byte_loop
    74  	MOVV	8(R4), R16
    75  	MOVV	8(R6), R17
    76  	ADDV	$16, R4
    77  	ADDV	$16, R6
    78  	SUBVU	$1, R14
    79  	BEQ	R16, R17, chunk16_loop
    80  	SUBV	$8, R4
    81  	SUBV	$8, R6
    82  
    83  byte_loop:
    84  	BEQ	R4, R12, samebytes
    85  	MOVBU	(R4), R8
    86  	ADDVU	$1, R4
    87  	MOVBU	(R6), R9
    88  	ADDVU	$1, R6
    89  	BEQ	R8, R9, byte_loop
    90  
    91  byte_cmp:
    92  	SGTU	R8, R9, R4 // R12 = 1 if (R8 > R9)
    93  	BNE	R0, R4, ret
    94  	MOVV	$-1, R4
    95  	JMP	ret
    96  
    97  samebytes:
    98  	SGTU	R5, R7, R8
    99  	SGTU	R7, R5, R9
   100  	SUBV	R9, R8, R4
   101  
   102  ret:
   103  #ifndef GOEXPERIMENT_regabiargs
   104  	MOVV	R4, (R13)
   105  #endif
   106  	RET
   107  

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