1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* $Id: memcpy.S,v 1.3 2001/07/27 11:50:52 gniibe Exp $ 3 * 4 * "memcpy" implementation of SuperH 5 * 6 * Copyright (C) 1999 Niibe Yutaka 7 * 8 */ 9 10 /* 11 * void *memcpy(void *dst, const void *src, size_t n); 12 * No overlap between the memory of DST and of SRC are assumed. 13 */ 14 15 #include <linux/linkage.h> 16 ENTRY(memcpy) 17 tst r6,r6 18 bt/s 9f ! if n=0, do nothing 19 mov r4,r0 20 sub r4,r5 ! From here, r5 has the distance to r0 21 add r6,r0 ! From here, r0 points the end of copying point 22 mov #12,r1 23 cmp/gt r6,r1 24 bt/s 7f ! if it's too small, copy a byte at once 25 add #-1,r5 26 add #1,r5 27 ! From here, r6 is free 28 ! 29 ! r4 --> [ ... ] DST [ ... ] SRC 30 ! [ ... ] [ ... ] 31 ! : : 32 ! r0 --> [ ... ] r0+r5 --> [ ... ] 33 ! 34 ! 35 mov r5,r1 36 mov #3,r2 37 and r2,r1 38 shll2 r1 39 mov r0,r3 ! Save the value on R0 to R3 40 mova jmptable,r0 41 add r1,r0 42 mov.l @r0,r1 43 jmp @r1 44 mov r3,r0 ! and back to R0 45 .balign 4 46 jmptable: 47 .long case0 48 .long case1 49 .long case2 50 .long case3 51 52 ! copy a byte at once 53 7: mov r4,r2 54 add #1,r2 55 8: 56 cmp/hi r2,r0 57 mov.b @(r0,r5),r1 58 bt/s 8b ! while (r0>r2) 59 mov.b r1,@-r0 60 9: 61 rts 62 nop 63 64 case0: 65 ! 66 ! GHIJ KLMN OPQR --> GHIJ KLMN OPQR 67 ! 68 ! First, align to long word boundary 69 mov r0,r3 70 and r2,r3 71 tst r3,r3 72 bt/s 2f 73 add #-4,r5 74 add #3,r5 75 1: dt r3 76 mov.b @(r0,r5),r1 77 bf/s 1b 78 mov.b r1,@-r0 79 ! 80 add #-3,r5 81 2: ! Second, copy a long word at once 82 mov r4,r2 83 add #7,r2 84 3: mov.l @(r0,r5),r1 85 cmp/hi r2,r0 86 bt/s 3b 87 mov.l r1,@-r0 88 ! 89 ! Third, copy a byte at once, if necessary 90 cmp/eq r4,r0 91 bt/s 9b 92 add #3,r5 93 bra 8b 94 add #-6,r2 95 96 case1: 97 ! 98 ! GHIJ KLMN OPQR --> ...G HIJK LMNO PQR. 99 ! 100 ! First, align to long word boundary 101 mov r0,r3 102 and r2,r3 103 tst r3,r3 104 bt/s 2f 105 add #-1,r5 106 1: dt r3 107 mov.b @(r0,r5),r1 108 bf/s 1b 109 mov.b r1,@-r0 110 ! 111 2: ! Second, read a long word and write a long word at once 112 mov.l @(r0,r5),r1 113 add #-4,r5 114 mov r4,r2 115 add #7,r2 116 ! 117 #ifdef __LITTLE_ENDIAN__ 118 3: mov r1,r3 ! RQPO 119 shll16 r3 120 shll8 r3 ! Oxxx 121 mov.l @(r0,r5),r1 ! NMLK 122 mov r1,r6 123 shlr8 r6 ! xNML 124 or r6,r3 ! ONML 125 cmp/hi r2,r0 126 bt/s 3b 127 mov.l r3,@-r0 128 #else 129 3: mov r1,r3 ! OPQR 130 shlr16 r3 131 shlr8 r3 ! xxxO 132 mov.l @(r0,r5),r1 ! KLMN 133 mov r1,r6 134 shll8 r6 ! LMNx 135 or r6,r3 ! LMNO 136 cmp/hi r2,r0 137 bt/s 3b 138 mov.l r3,@-r0 139 #endif 140 ! 141 ! Third, copy a byte at once, if necessary 142 cmp/eq r4,r0 143 bt/s 9b 144 add #4,r5 145 bra 8b 146 add #-6,r2 147 148 case2: 149 ! 150 ! GHIJ KLMN OPQR --> ..GH IJKL MNOP QR.. 151 ! 152 ! First, align to word boundary 153 tst #1,r0 154 bt/s 2f 155 add #-1,r5 156 mov.b @(r0,r5),r1 157 mov.b r1,@-r0 158 ! 159 2: ! Second, read a word and write a word at once 160 add #-1,r5 161 mov r4,r2 162 add #3,r2 163 ! 164 3: mov.w @(r0,r5),r1 165 cmp/hi r2,r0 166 bt/s 3b 167 mov.w r1,@-r0 168 ! 169 ! Third, copy a byte at once, if necessary 170 cmp/eq r4,r0 171 bt/s 9b 172 add #1,r5 173 mov.b @(r0,r5),r1 174 rts 175 mov.b r1,@-r0 176 177 case3: 178 ! 179 ! GHIJ KLMN OPQR --> .GHI JKLM NOPQ R... 180 ! 181 ! First, align to long word boundary 182 mov r0,r3 183 and r2,r3 184 tst r3,r3 185 bt/s 2f 186 add #-1,r5 187 1: dt r3 188 mov.b @(r0,r5),r1 189 bf/s 1b 190 mov.b r1,@-r0 191 ! 192 2: ! Second, read a long word and write a long word at once 193 add #-2,r5 194 mov.l @(r0,r5),r1 195 add #-4,r5 196 mov r4,r2 197 add #7,r2 198 ! 199 #ifdef __LITTLE_ENDIAN__ 200 3: mov r1,r3 ! RQPO 201 shll8 r3 ! QPOx 202 mov.l @(r0,r5),r1 ! NMLK 203 mov r1,r6 204 shlr16 r6 205 shlr8 r6 ! xxxN 206 or r6,r3 ! QPON 207 cmp/hi r2,r0 208 bt/s 3b 209 mov.l r3,@-r0 210 #else 211 3: mov r1,r3 ! OPQR 212 shlr8 r3 ! xOPQ 213 mov.l @(r0,r5),r1 ! KLMN 214 mov r1,r6 215 shll16 r6 216 shll8 r6 ! Nxxx 217 or r6,r3 ! NOPQ 218 cmp/hi r2,r0 219 bt/s 3b 220 mov.l r3,@-r0 221 #endif 222 ! 223 ! Third, copy a byte at once, if necessary 224 cmp/eq r4,r0 225 bt/s 9b 226 add #6,r5 227 bra 8b 228 add #-6,r2 229