arch/arm26/lib/csumpartialcopygeneric.S

   1 /*
   2  *  linux/arch/arm26/lib/csumpartialcopygeneric.S
   3  *
   4  *  Copyright (C) 1995-2001 Russell King
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * JMA 01/06/03 Commented out some shl0s; probobly irrelevant to arm26
  11  *
  12  */
  13
  14 /*
  15  * unsigned int
  16  * csum_partial_copy_xxx(const char *src, char *dst, int len, int sum, )
  17  *  r0 = src, r1 = dst, r2 = len, r3 = sum
  18  *  Returns : r0 = checksum
  19  *
  20  * Note that 'tst' and 'teq' preserve the carry flag.
  21  */
  22
  23 /* Quick hack */
  24                 .macro  save_regs
  25                 stmfd   sp!, {r1, r4 - r8, fp, ip, lr, pc}
  26                 .endm
  27
  28 /* end Quick Hack */
  29
  30 src     .req    r0
  31 dst     .req    r1
  32 len     .req    r2
  33 sum     .req    r3
  34
  35 .zero:          mov     r0, sum
  36                 load_regs       ea
  37
  38                 /*
  39                  * Align an unaligned destination pointer.  We know that
  40                  * we have >= 8 bytes here, so we don't need to check
  41                  * the length.  Note that the source pointer hasn't been
  42                  * aligned yet.
  43                  */
  44 .dst_unaligned: tst     dst, #1
  45                 beq     .dst_16bit
  46
  47                 load1b  ip
  48                 sub     len, len, #1
  49                 adcs    sum, sum, ip, lsl #byte(1)      @ update checksum
  50                 strb    ip, [dst], #1
  51                 tst     dst, #2
  52                 moveq   pc, lr                  @ dst is now 32bit aligned
  53
  54 .dst_16bit:     load2b  r8, ip
  55                 sub     len, len, #2
  56                 adcs    sum, sum, r8, lsl #byte(0)
  57                 strb    r8, [dst], #1
  58                 adcs    sum, sum, ip, lsl #byte(1)
  59                 strb    ip, [dst], #1
  60                 mov     pc, lr                  @ dst is now 32bit aligned
  61
  62                 /*
  63                  * Handle 0 to 7 bytes, with any alignment of source and
  64                  * destination pointers.  Note that when we get here, C = 0
  65                  */
  66 .less8:         teq     len, #0                 @ check for zero count
  67                 beq     .zero
  68
  69                 /* we must have at least one byte. */
  70                 tst     dst, #1                 @ dst 16-bit aligned
  71                 beq     .less8_aligned
  72
  73                 /* Align dst */
  74                 load1b  ip
  75                 sub     len, len, #1
  76                 adcs    sum, sum, ip, lsl #byte(1)      @ update checksum
  77                 strb    ip, [dst], #1
  78                 tst     len, #6
  79                 beq     .less8_byteonly
  80
  81 1:              load2b  r8, ip
  82                 sub     len, len, #2
  83                 adcs    sum, sum, r8, lsl #byte(0)
  84                 strb    r8, [dst], #1
  85                 adcs    sum, sum, ip, lsl #byte(1)
  86                 strb    ip, [dst], #1
  87 .less8_aligned: tst     len, #6
  88                 bne     1b
  89 .less8_byteonly:
  90                 tst     len, #1
  91                 beq     .done
  92                 load1b  r8
  93                 adcs    sum, sum, r8, lsl #byte(0)      @ update checksum
  94                 strb    r8, [dst], #1
  95                 b       .done
  96
  97 FN_ENTRY
  98                 mov     ip, sp
  99                 save_regs
 100                 sub     fp, ip, #4
 101
 102                 cmp     len, #8                 @ Ensure that we have at least
 103                 blo     .less8                  @ 8 bytes to copy.
 104
 105                 adds    sum, sum, #0            @ C = 0
 106                 tst     dst, #3                 @ Test destination alignment
 107                 blne    .dst_unaligned          @ align destination, return here
 108
 109                 /*
 110                  * Ok, the dst pointer is now 32bit aligned, and we know
 111                  * that we must have more than 4 bytes to copy.  Note
 112                  * that C contains the carry from the dst alignment above.
 113                  */
 114
 115                 tst     src, #3                 @ Test source alignment
 116                 bne     .src_not_aligned
 117
 118                 /* Routine for src & dst aligned */
 119
 120                 bics    ip, len, #15
 121                 beq     2f
 122
 123 1:              load4l  r4, r5, r6, r7
 124                 stmia   dst!, {r4, r5, r6, r7}
 125                 adcs    sum, sum, r4
 126                 adcs    sum, sum, r5
 127                 adcs    sum, sum, r6
 128                 adcs    sum, sum, r7
 129                 sub     ip, ip, #16
 130                 teq     ip, #0
 131                 bne     1b
 132
 133 2:              ands    ip, len, #12
 134                 beq     4f
 135                 tst     ip, #8
 136                 beq     3f
 137                 load2l  r4, r5
 138                 stmia   dst!, {r4, r5}
 139                 adcs    sum, sum, r4
 140                 adcs    sum, sum, r5
 141                 tst     ip, #4
 142                 beq     4f
 143
 144 3:              load1l  r4
 145                 str     r4, [dst], #4
 146                 adcs    sum, sum, r4
 147
 148 4:              ands    len, len, #3
 149                 beq     .done
 150                 load1l  r4
 151                 tst     len, #2
 152 /*              mov     r5, r4, lsr #byte(0)
 153 FIXME? 0 Shift anyhow!
 154 */
 155                 beq     .exit
 156                 adcs    sum, sum, r4, push #16
 157                 strb    r5, [dst], #1
 158                 mov     r5, r4, lsr #byte(1)
 159                 strb    r5, [dst], #1
 160                 mov     r5, r4, lsr #byte(2)
 161 .exit:          tst     len, #1
 162                 strneb  r5, [dst], #1
 163                 andne   r5, r5, #255
 164                 adcnes  sum, sum, r5, lsl #byte(0)
 165
 166                 /*
 167                  * If the dst pointer was not 16-bit aligned, we
 168                  * need to rotate the checksum here to get around
 169                  * the inefficient byte manipulations in the
 170                  * architecture independent code.
 171                  */
 172 .done:          adc     r0, sum, #0
 173                 ldr     sum, [sp, #0]           @ dst
 174                 tst     sum, #1
 175                 movne   sum, r0, lsl #8
 176                 orrne   r0, sum, r0, lsr #24
 177                 load_regs       ea
 178
 179 .src_not_aligned:
 180                 adc     sum, sum, #0            @ include C from dst alignment
 181                 and     ip, src, #3
 182                 bic     src, src, #3
 183                 load1l  r5
 184                 cmp     ip, #2
 185                 beq     .src2_aligned
 186                 bhi     .src3_aligned
 187                 mov     r4, r5, pull #8         @ C = 0
 188                 bics    ip, len, #15
 189                 beq     2f
 190 1:              load4l  r5, r6, r7, r8
 191                 orr     r4, r4, r5, push #24
 192                 mov     r5, r5, pull #8
 193                 orr     r5, r5, r6, push #24
 194                 mov     r6, r6, pull #8
 195                 orr     r6, r6, r7, push #24
 196                 mov     r7, r7, pull #8
 197                 orr     r7, r7, r8, push #24
 198                 stmia   dst!, {r4, r5, r6, r7}
 199                 adcs    sum, sum, r4
 200                 adcs    sum, sum, r5
 201                 adcs    sum, sum, r6
 202                 adcs    sum, sum, r7
 203                 mov     r4, r8, pull #8
 204                 sub     ip, ip, #16
 205                 teq     ip, #0
 206                 bne     1b
 207 2:              ands    ip, len, #12
 208                 beq     4f
 209                 tst     ip, #8
 210                 beq     3f
 211                 load2l  r5, r6
 212                 orr     r4, r4, r5, push #24
 213                 mov     r5, r5, pull #8
 214                 orr     r5, r5, r6, push #24
 215                 stmia   dst!, {r4, r5}
 216                 adcs    sum, sum, r4
 217                 adcs    sum, sum, r5
 218                 mov     r4, r6, pull #8
 219                 tst     ip, #4
 220                 beq     4f
 221 3:              load1l  r5
 222                 orr     r4, r4, r5, push #24
 223                 str     r4, [dst], #4
 224                 adcs    sum, sum, r4
 225                 mov     r4, r5, pull #8
 226 4:              ands    len, len, #3
 227                 beq     .done
 228 /*              mov     r5, r4, lsr #byte(0)
 229 FIXME? 0 Shift anyhow
 230 */
 231                 tst     len, #2
 232                 beq     .exit
 233                 adcs    sum, sum, r4, push #16
 234                 strb    r5, [dst], #1
 235                 mov     r5, r4, lsr #byte(1)
 236                 strb    r5, [dst], #1
 237                 mov     r5, r4, lsr #byte(2)
 238                 b       .exit
 239
 240 .src2_aligned:  mov     r4, r5, pull #16
 241                 adds    sum, sum, #0
 242                 bics    ip, len, #15
 243                 beq     2f
 244 1:              load4l  r5, r6, r7, r8
 245                 orr     r4, r4, r5, push #16
 246                 mov     r5, r5, pull #16
 247                 orr     r5, r5, r6, push #16
 248                 mov     r6, r6, pull #16
 249                 orr     r6, r6, r7, push #16
 250                 mov     r7, r7, pull #16
 251                 orr     r7, r7, r8, push #16
 252                 stmia   dst!, {r4, r5, r6, r7}
 253                 adcs    sum, sum, r4
 254                 adcs    sum, sum, r5
 255                 adcs    sum, sum, r6
 256                 adcs    sum, sum, r7
 257                 mov     r4, r8, pull #16
 258                 sub     ip, ip, #16
 259                 teq     ip, #0
 260                 bne     1b
 261 2:              ands    ip, len, #12
 262                 beq     4f
 263                 tst     ip, #8
 264                 beq     3f
 265                 load2l  r5, r6
 266                 orr     r4, r4, r5, push #16
 267                 mov     r5, r5, pull #16
 268                 orr     r5, r5, r6, push #16
 269                 stmia   dst!, {r4, r5}
 270                 adcs    sum, sum, r4
 271                 adcs    sum, sum, r5
 272                 mov     r4, r6, pull #16
 273                 tst     ip, #4
 274                 beq     4f
 275 3:              load1l  r5
 276                 orr     r4, r4, r5, push #16
 277                 str     r4, [dst], #4
 278                 adcs    sum, sum, r4
 279                 mov     r4, r5, pull #16
 280 4:              ands    len, len, #3
 281                 beq     .done
 282 /*              mov     r5, r4, lsr #byte(0)
 283 FIXME? 0 Shift anyhow
 284 */
 285                 tst     len, #2
 286                 beq     .exit
 287                 adcs    sum, sum, r4
 288                 strb    r5, [dst], #1
 289                 mov     r5, r4, lsr #byte(1)
 290                 strb    r5, [dst], #1
 291                 tst     len, #1
 292                 beq     .done
 293                 load1b  r5
 294                 b       .exit
 295
 296 .src3_aligned:  mov     r4, r5, pull #24
 297                 adds    sum, sum, #0
 298                 bics    ip, len, #15
 299                 beq     2f
 300 1:              load4l  r5, r6, r7, r8
 301                 orr     r4, r4, r5, push #8
 302                 mov     r5, r5, pull #24
 303                 orr     r5, r5, r6, push #8
 304                 mov     r6, r6, pull #24
 305                 orr     r6, r6, r7, push #8
 306                 mov     r7, r7, pull #24
 307                 orr     r7, r7, r8, push #8
 308                 stmia   dst!, {r4, r5, r6, r7}
 309                 adcs    sum, sum, r4
 310                 adcs    sum, sum, r5
 311                 adcs    sum, sum, r6
 312                 adcs    sum, sum, r7
 313                 mov     r4, r8, pull #24
 314                 sub     ip, ip, #16
 315                 teq     ip, #0
 316                 bne     1b
 317 2:              ands    ip, len, #12
 318                 beq     4f
 319                 tst     ip, #8
 320                 beq     3f
 321                 load2l  r5, r6
 322                 orr     r4, r4, r5, push #8
 323                 mov     r5, r5, pull #24
 324                 orr     r5, r5, r6, push #8
 325                 stmia   dst!, {r4, r5}
 326                 adcs    sum, sum, r4
 327                 adcs    sum, sum, r5
 328                 mov     r4, r6, pull #24
 329                 tst     ip, #4
 330                 beq     4f
 331 3:              load1l  r5
 332                 orr     r4, r4, r5, push #8
 333                 str     r4, [dst], #4
 334                 adcs    sum, sum, r4
 335                 mov     r4, r5, pull #24
 336 4:              ands    len, len, #3
 337                 beq     .done
 338 /*              mov     r5, r4, lsr #byte(0)
 339 FIXME? 0 Shift anyhow
 340 */
 341                 tst     len, #2
 342                 beq     .exit
 343                 strb    r5, [dst], #1
 344                 adcs    sum, sum, r4
 345                 load1l  r4
 346 /*              mov     r5, r4, lsr #byte(0)
 347 FIXME? 0 Shift anyhow
 348 */
 349                 strb    r5, [dst], #1
 350                 adcs    sum, sum, r4, push #24
 351                 mov     r5, r4, lsr #byte(1)
 352                 b       .exit