memmove_mipsx.s

Documentation: runtime

     1// Copyright 2016 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 mips || mipsle
     6
     7#include "textflag.h"
     8
     9#ifdef GOARCH_mips
    10#define MOVWHI  MOVWL
    11#define MOVWLO  MOVWR
    12#else
    13#define MOVWHI  MOVWR
    14#define MOVWLO  MOVWL
    15#endif
    16
    17// See memmove Go doc for important implementation constraints.
    18
    19// func memmove(to, from unsafe.Pointer, n uintptr)
    20TEXT runtime·memmove(SB),NOSPLIT,$-0-12
    21	MOVW	n+8(FP), R3
    22	MOVW	from+4(FP), R2
    23	MOVW	to+0(FP), R1
    24
    25	ADDU	R3, R2, R4	// end pointer for source
    26	ADDU	R3, R1, R5	// end pointer for destination
    27
    28	// if destination is ahead of source, start at the end of the buffer and go backward.
    29	SGTU	R1, R2, R6
    30	BNE	R6, backward
    31
    32	// if less than 4 bytes, use byte by byte copying
    33	SGTU	$4, R3, R6
    34	BNE	R6, f_small_copy
    35
    36	// align destination to 4 bytes
    37	AND	$3, R1, R6
    38	BEQ	R6, f_dest_aligned
    39	SUBU	R1, R0, R6
    40	AND	$3, R6
    41	MOVWHI	0(R2), R7
    42	SUBU	R6, R3
    43	MOVWLO	3(R2), R7
    44	ADDU	R6, R2
    45	MOVWHI	R7, 0(R1)
    46	ADDU	R6, R1
    47
    48f_dest_aligned:
    49	AND	$31, R3, R7
    50	AND	$3, R3, R6
    51	SUBU	R7, R5, R7	// end pointer for 32-byte chunks
    52	SUBU	R6, R5, R6	// end pointer for 4-byte chunks
    53
    54	// if source is not aligned, use unaligned reads
    55	AND	$3, R2, R8
    56	BNE	R8, f_large_ua
    57
    58f_large:
    59	BEQ	R1, R7, f_words
    60	ADDU	$32, R1
    61	MOVW	0(R2), R8
    62	MOVW	4(R2), R9
    63	MOVW	8(R2), R10
    64	MOVW	12(R2), R11
    65	MOVW	16(R2), R12
    66	MOVW	20(R2), R13
    67	MOVW	24(R2), R14
    68	MOVW	28(R2), R15
    69	ADDU	$32, R2
    70	MOVW	R8, -32(R1)
    71	MOVW	R9, -28(R1)
    72	MOVW	R10, -24(R1)
    73	MOVW	R11, -20(R1)
    74	MOVW	R12, -16(R1)
    75	MOVW	R13, -12(R1)
    76	MOVW	R14, -8(R1)
    77	MOVW	R15, -4(R1)
    78	JMP	f_large
    79
    80f_words:
    81	BEQ	R1, R6, f_tail
    82	ADDU	$4, R1
    83	MOVW	0(R2), R8
    84	ADDU	$4, R2
    85	MOVW	R8, -4(R1)
    86	JMP	f_words
    87
    88f_tail:
    89	BEQ	R1, R5, ret
    90	MOVWLO	-1(R4), R8
    91	MOVWLO	R8, -1(R5)
    92
    93ret:
    94	RET
    95
    96f_large_ua:
    97	BEQ	R1, R7, f_words_ua
    98	ADDU	$32, R1
    99	MOVWHI	0(R2), R8
   100	MOVWHI	4(R2), R9
   101	MOVWHI	8(R2), R10
   102	MOVWHI	12(R2), R11
   103	MOVWHI	16(R2), R12
   104	MOVWHI	20(R2), R13
   105	MOVWHI	24(R2), R14
   106	MOVWHI	28(R2), R15
   107	MOVWLO	3(R2), R8
   108	MOVWLO	7(R2), R9
   109	MOVWLO	11(R2), R10
   110	MOVWLO	15(R2), R11
   111	MOVWLO	19(R2), R12
   112	MOVWLO	23(R2), R13
   113	MOVWLO	27(R2), R14
   114	MOVWLO	31(R2), R15
   115	ADDU	$32, R2
   116	MOVW	R8, -32(R1)
   117	MOVW	R9, -28(R1)
   118	MOVW	R10, -24(R1)
   119	MOVW	R11, -20(R1)
   120	MOVW	R12, -16(R1)
   121	MOVW	R13, -12(R1)
   122	MOVW	R14, -8(R1)
   123	MOVW	R15, -4(R1)
   124	JMP	f_large_ua
   125
   126f_words_ua:
   127	BEQ	R1, R6, f_tail_ua
   128	MOVWHI	0(R2), R8
   129	ADDU	$4, R1
   130	MOVWLO	3(R2), R8
   131	ADDU	$4, R2
   132	MOVW	R8, -4(R1)
   133	JMP	f_words_ua
   134
   135f_tail_ua:
   136	BEQ	R1, R5, ret
   137	MOVWHI	-4(R4), R8
   138	MOVWLO	-1(R4), R8
   139	MOVWLO	R8, -1(R5)
   140	JMP	ret
   141
   142f_small_copy:
   143	BEQ	R1, R5, ret
   144	ADDU	$1, R1
   145	MOVB	0(R2), R6
   146	ADDU	$1, R2
   147	MOVB	R6, -1(R1)
   148	JMP	f_small_copy
   149
   150backward:
   151	SGTU	$4, R3, R6
   152	BNE	R6, b_small_copy
   153
   154	AND	$3, R5, R6
   155	BEQ	R6, b_dest_aligned
   156	MOVWHI	-4(R4), R7
   157	SUBU	R6, R3
   158	MOVWLO	-1(R4), R7
   159	SUBU	R6, R4
   160	MOVWLO	R7, -1(R5)
   161	SUBU	R6, R5
   162
   163b_dest_aligned:
   164	AND	$31, R3, R7
   165	AND	$3, R3, R6
   166	ADDU	R7, R1, R7
   167	ADDU	R6, R1, R6
   168
   169	AND	$3, R4, R8
   170	BNE	R8, b_large_ua
   171
   172b_large:
   173	BEQ	R5, R7, b_words
   174	ADDU	$-32, R5
   175	MOVW	-4(R4), R8
   176	MOVW	-8(R4), R9
   177	MOVW	-12(R4), R10
   178	MOVW	-16(R4), R11
   179	MOVW	-20(R4), R12
   180	MOVW	-24(R4), R13
   181	MOVW	-28(R4), R14
   182	MOVW	-32(R4), R15
   183	ADDU	$-32, R4
   184	MOVW	R8, 28(R5)
   185	MOVW	R9, 24(R5)
   186	MOVW	R10, 20(R5)
   187	MOVW	R11, 16(R5)
   188	MOVW	R12, 12(R5)
   189	MOVW	R13, 8(R5)
   190	MOVW	R14, 4(R5)
   191	MOVW	R15, 0(R5)
   192	JMP	b_large
   193
   194b_words:
   195	BEQ	R5, R6, b_tail
   196	ADDU	$-4, R5
   197	MOVW	-4(R4), R8
   198	ADDU	$-4, R4
   199	MOVW	R8, 0(R5)
   200	JMP	b_words
   201
   202b_tail:
   203	BEQ	R5, R1, ret
   204	MOVWHI	0(R2), R8	// R2 and R1 have the same alignment so we don't need to load a whole word
   205	MOVWHI	R8, 0(R1)
   206	JMP	ret
   207
   208b_large_ua:
   209	BEQ	R5, R7, b_words_ua
   210	ADDU	$-32, R5
   211	MOVWHI	-4(R4), R8
   212	MOVWHI	-8(R4), R9
   213	MOVWHI	-12(R4), R10
   214	MOVWHI	-16(R4), R11
   215	MOVWHI	-20(R4), R12
   216	MOVWHI	-24(R4), R13
   217	MOVWHI	-28(R4), R14
   218	MOVWHI	-32(R4), R15
   219	MOVWLO	-1(R4), R8
   220	MOVWLO	-5(R4), R9
   221	MOVWLO	-9(R4), R10
   222	MOVWLO	-13(R4), R11
   223	MOVWLO	-17(R4), R12
   224	MOVWLO	-21(R4), R13
   225	MOVWLO	-25(R4), R14
   226	MOVWLO	-29(R4), R15
   227	ADDU	$-32, R4
   228	MOVW	R8, 28(R5)
   229	MOVW	R9, 24(R5)
   230	MOVW	R10, 20(R5)
   231	MOVW	R11, 16(R5)
   232	MOVW	R12, 12(R5)
   233	MOVW	R13, 8(R5)
   234	MOVW	R14, 4(R5)
   235	MOVW	R15, 0(R5)
   236	JMP	b_large_ua
   237
   238b_words_ua:
   239	BEQ	R5, R6, b_tail_ua
   240	MOVWHI	-4(R4), R8
   241	ADDU	$-4, R5
   242	MOVWLO	-1(R4), R8
   243	ADDU	$-4, R4
   244	MOVW	R8, 0(R5)
   245	JMP	b_words_ua
   246
   247b_tail_ua:
   248	BEQ	R5, R1, ret
   249	MOVWHI	(R2), R8
   250	MOVWLO	3(R2), R8
   251	MOVWHI	R8, 0(R1)
   252	JMP ret
   253
   254b_small_copy:
   255	BEQ	R5, R1, ret
   256	ADDU	$-1, R5
   257	MOVB	-1(R4), R6
   258	ADDU	$-1, R4
   259	MOVB	R6, 0(R5)
   260	JMP	b_small_copy
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