github.com/dannin/go@v0.0.0-20161031215817-d35dfd405eaa/src/runtime/memmove_mips64x.s (about)

     1  // Copyright 2015 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 mips64 mips64le
     6  
     7  #include "textflag.h"
     8  
     9  // void runtime·memmove(void*, void*, uintptr)
    10  TEXT runtime·memmove(SB), NOSPLIT, $-8-24
    11  	MOVV	to+0(FP), R1
    12  	MOVV	from+8(FP), R2
    13  	MOVV	n+16(FP), R3
    14  	BNE	R3, check
    15  	RET
    16  
    17  check:
    18  	SGTU	R1, R2, R4
    19  	BNE	R4, backward
    20  
    21  	ADDV	R1, R3, R6 // end pointer
    22  
    23  	// if the two pointers are not of same alignments, do byte copying
    24  	SUBVU	R2, R1, R4
    25  	AND	$7, R4
    26  	BNE	R4, out
    27  
    28  	// if less than 8 bytes, do byte copying
    29  	SGTU	$8, R3, R4
    30  	BNE	R4, out
    31  
    32  	// do one byte at a time until 8-aligned
    33  	AND	$7, R1, R5
    34  	BEQ	R5, words
    35  	MOVB	(R2), R4
    36  	ADDV	$1, R2
    37  	MOVB	R4, (R1)
    38  	ADDV	$1, R1
    39  	JMP	-6(PC)
    40  
    41  words:
    42  	// do 8 bytes at a time if there is room
    43  	ADDV	$-7, R6, R3 // R3 is end pointer-7
    44  
    45  	SGTU	R3, R1, R5
    46  	BEQ	R5, out
    47  	MOVV	(R2), R4
    48  	ADDV	$8, R2
    49  	MOVV	R4, (R1)
    50  	ADDV	$8, R1
    51  	JMP	-6(PC)
    52  
    53  out:
    54  	BEQ	R1, R6, done
    55  	MOVB	(R2), R4
    56  	ADDV	$1, R2
    57  	MOVB	R4, (R1)
    58  	ADDV	$1, R1
    59  	JMP	-5(PC)
    60  done:
    61  	RET
    62  
    63  backward:
    64  	ADDV	R3, R2 // from-end pointer
    65  	ADDV	R1, R3, R6 // to-end pointer
    66  
    67  	// if the two pointers are not of same alignments, do byte copying
    68  	SUBVU	R6, R2, R4
    69  	AND	$7, R4
    70  	BNE	R4, out1
    71  
    72  	// if less than 8 bytes, do byte copying
    73  	SGTU	$8, R3, R4
    74  	BNE	R4, out1
    75  
    76  	// do one byte at a time until 8-aligned
    77  	AND	$7, R6, R5
    78  	BEQ	R5, words1
    79  	ADDV	$-1, R2
    80  	MOVB	(R2), R4
    81  	ADDV	$-1, R6
    82  	MOVB	R4, (R6)
    83  	JMP	-6(PC)
    84  
    85  words1:
    86  	// do 8 bytes at a time if there is room
    87  	ADDV	$7, R1, R3 // R3 is start pointer+7
    88  
    89  	SGTU	R6, R3, R5
    90  	BEQ	R5, out1
    91  	ADDV	$-8, R2
    92  	MOVV	(R2), R4
    93  	ADDV	$-8, R6
    94  	MOVV	R4, (R6)
    95  	JMP	-6(PC)
    96  
    97  out1:
    98  	BEQ	R1, R6, done1
    99  	ADDV	$-1, R2
   100  	MOVB	(R2), R4
   101  	ADDV	$-1, R6
   102  	MOVB	R4, (R6)
   103  	JMP	-5(PC)
   104  done1:
   105  	RET