github.com/sandwichdev/go-internals@v0.0.0-20210605002614-12311ac6b2c5/bytealg/compare_wasm.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  #include "go_asm.h"
     6  #include "textflag.h"
     7  
     8  TEXT ·Compare(SB), NOSPLIT, $0-56
     9  	Get SP
    10  	I64Load a_base+0(FP)
    11  	I64Load a_len+8(FP)
    12  	I64Load b_base+24(FP)
    13  	I64Load b_len+32(FP)
    14  	Call cmpbody<>(SB)
    15  	I64Store ret+48(FP)
    16  	RET
    17  
    18  TEXT runtime·cmpstring(SB), NOSPLIT, $0-40
    19  	Get SP
    20  	I64Load a_base+0(FP)
    21  	I64Load a_len+8(FP)
    22  	I64Load b_base+16(FP)
    23  	I64Load b_len+24(FP)
    24  	Call cmpbody<>(SB)
    25  	I64Store ret+32(FP)
    26  	RET
    27  
    28  // params: a, alen, b, blen
    29  // ret: -1/0/1
    30  TEXT cmpbody<>(SB), NOSPLIT, $0-0
    31  	// len = min(alen, blen)
    32  	Get R1
    33  	Get R3
    34  	Get R1
    35  	Get R3
    36  	I64LtU
    37  	Select
    38  	Set R4
    39  
    40  	Get R0
    41  	I32WrapI64
    42  	Get R2
    43  	I32WrapI64
    44  	Get R4
    45  	I32WrapI64
    46  	Call memcmp<>(SB)
    47  	I64ExtendI32S
    48  	Tee R5
    49  
    50  	I64Eqz
    51  	If
    52  		// check length
    53  		Get R1
    54  		Get R3
    55  		I64Sub
    56  		Set R5
    57  	End
    58  
    59  	I64Const $0
    60  	I64Const $-1
    61  	I64Const $1
    62  	Get R5
    63  	I64Const $0
    64  	I64LtS
    65  	Select
    66  	Get R5
    67  	I64Eqz
    68  	Select
    69  	Return
    70  
    71  // compiled with emscripten
    72  // params: a, b, len
    73  // ret: <0/0/>0
    74  TEXT memcmp<>(SB), NOSPLIT, $0-0
    75  	Get R2
    76  	If $1
    77  	Loop
    78  	Get R0
    79  	I32Load8S $0
    80  	Tee R3
    81  	Get R1
    82  	I32Load8S $0
    83  	Tee R4
    84  	I32Eq
    85  	If
    86  	Get R0
    87  	I32Const $1
    88  	I32Add
    89  	Set R0
    90  	Get R1
    91  	I32Const $1
    92  	I32Add
    93  	Set R1
    94  	I32Const $0
    95  	Get R2
    96  	I32Const $-1
    97  	I32Add
    98  	Tee R2
    99  	I32Eqz
   100  	BrIf $3
   101  	Drop
   102  	Br $1
   103  	End
   104  	End
   105  	Get R3
   106  	I32Const $255
   107  	I32And
   108  	Get R4
   109  	I32Const $255
   110  	I32And
   111  	I32Sub
   112  	Else
   113  	I32Const $0
   114  	End
   115  	Return