Text file src/runtime/memmove_mips64x.s

     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	// func memmove(to, from unsafe.Pointer, n uintptr)
    10	TEXT runtime·memmove(SB), NOSPLIT|NOFRAME, $0-24
    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

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