arch/powerpc/lib/copy_32.S

   1 /*
   2  * Memory copy functions for 32-bit PowerPC.
   3  *
   4  * Copyright (C) 1996-2005 Paul Mackerras.
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11 #include <asm/processor.h>
  12 #include <asm/cache.h>
  13 #include <asm/errno.h>
  14 #include <asm/ppc_asm.h>
  15
  16 #define COPY_16_BYTES           \
  17         lwz     r7,4(r4);       \
  18         lwz     r8,8(r4);       \
  19         lwz     r9,12(r4);      \
  20         lwzu    r10,16(r4);     \
  21         stw     r7,4(r6);       \
  22         stw     r8,8(r6);       \
  23         stw     r9,12(r6);      \
  24         stwu    r10,16(r6)
  25
  26 #define COPY_16_BYTES_WITHEX(n) \
  27 8 ## n ## 0:                    \
  28         lwz     r7,4(r4);       \
  29 8 ## n ## 1:                    \
  30         lwz     r8,8(r4);       \
  31 8 ## n ## 2:                    \
  32         lwz     r9,12(r4);      \
  33 8 ## n ## 3:                    \
  34         lwzu    r10,16(r4);     \
  35 8 ## n ## 4:                    \
  36         stw     r7,4(r6);       \
  37 8 ## n ## 5:                    \
  38         stw     r8,8(r6);       \
  39 8 ## n ## 6:                    \
  40         stw     r9,12(r6);      \
  41 8 ## n ## 7:                    \
  42         stwu    r10,16(r6)
  43
  44 #define COPY_16_BYTES_EXCODE(n)                 \
  45 9 ## n ## 0:                                    \
  46         addi    r5,r5,-(16 * n);                \
  47         b       104f;                           \
  48 9 ## n ## 1:                                    \
  49         addi    r5,r5,-(16 * n);                \
  50         b       105f;                           \
  51 .section __ex_table,"a";                        \
  52         .align  2;                              \
  53         .long   8 ## n ## 0b,9 ## n ## 0b;      \
  54         .long   8 ## n ## 1b,9 ## n ## 0b;      \
  55         .long   8 ## n ## 2b,9 ## n ## 0b;      \
  56         .long   8 ## n ## 3b,9 ## n ## 0b;      \
  57         .long   8 ## n ## 4b,9 ## n ## 1b;      \
  58         .long   8 ## n ## 5b,9 ## n ## 1b;      \
  59         .long   8 ## n ## 6b,9 ## n ## 1b;      \
  60         .long   8 ## n ## 7b,9 ## n ## 1b;      \
  61         .text
  62
  63         .text
  64         .stabs  "arch/powerpc/lib/",N_SO,0,0,0f
  65         .stabs  "copy_32.S",N_SO,0,0,0f
  66 0:
  67
  68 CACHELINE_BYTES = L1_CACHE_BYTES
  69 LG_CACHELINE_BYTES = L1_CACHE_SHIFT
  70 CACHELINE_MASK = (L1_CACHE_BYTES-1)
  71
  72 _GLOBAL(memset)
  73         rlwimi  r4,r4,8,16,23
  74         rlwimi  r4,r4,16,0,15
  75         addi    r6,r3,-4
  76         cmplwi  0,r5,4
  77         blt     7f
  78         stwu    r4,4(r6)
  79         beqlr
  80         andi.   r0,r6,3
  81         add     r5,r0,r5
  82         subf    r6,r0,r6
  83         srwi    r0,r5,2
  84         mtctr   r0
  85         bdz     6f
  86 1:      stwu    r4,4(r6)
  87         bdnz    1b
  88 6:      andi.   r5,r5,3
  89 7:      cmpwi   0,r5,0
  90         beqlr
  91         mtctr   r5
  92         addi    r6,r6,3
  93 8:      stbu    r4,1(r6)
  94         bdnz    8b
  95         blr
  96
  97 _GLOBAL(memmove)
  98         cmplw   0,r3,r4
  99         bgt     backwards_memcpy
 100         /* fall through */
 101
 102 _GLOBAL(memcpy)
 103         srwi.   r7,r5,3
 104         addi    r6,r3,-4
 105         addi    r4,r4,-4
 106         beq     2f                      /* if less than 8 bytes to do */
 107         andi.   r0,r6,3                 /* get dest word aligned */
 108         mtctr   r7
 109         bne     5f
 110 1:      lwz     r7,4(r4)
 111         lwzu    r8,8(r4)
 112         stw     r7,4(r6)
 113         stwu    r8,8(r6)
 114         bdnz    1b
 115         andi.   r5,r5,7
 116 2:      cmplwi  0,r5,4
 117         blt     3f
 118         lwzu    r0,4(r4)
 119         addi    r5,r5,-4
 120         stwu    r0,4(r6)
 121 3:      cmpwi   0,r5,0
 122         beqlr
 123         mtctr   r5
 124         addi    r4,r4,3
 125         addi    r6,r6,3
 126 4:      lbzu    r0,1(r4)
 127         stbu    r0,1(r6)
 128         bdnz    4b
 129         blr
 130 5:      subfic  r0,r0,4
 131         mtctr   r0
 132 6:      lbz     r7,4(r4)
 133         addi    r4,r4,1
 134         stb     r7,4(r6)
 135         addi    r6,r6,1
 136         bdnz    6b
 137         subf    r5,r0,r5
 138         rlwinm. r7,r5,32-3,3,31
 139         beq     2b
 140         mtctr   r7
 141         b       1b
 142
 143 _GLOBAL(backwards_memcpy)
 144         rlwinm. r7,r5,32-3,3,31         /* r0 = r5 >> 3 */
 145         add     r6,r3,r5
 146         add     r4,r4,r5
 147         beq     2f
 148         andi.   r0,r6,3
 149         mtctr   r7
 150         bne     5f
 151 1:      lwz     r7,-4(r4)
 152         lwzu    r8,-8(r4)
 153         stw     r7,-4(r6)
 154         stwu    r8,-8(r6)
 155         bdnz    1b
 156         andi.   r5,r5,7
 157 2:      cmplwi  0,r5,4
 158         blt     3f
 159         lwzu    r0,-4(r4)
 160         subi    r5,r5,4
 161         stwu    r0,-4(r6)
 162 3:      cmpwi   0,r5,0
 163         beqlr
 164         mtctr   r5
 165 4:      lbzu    r0,-1(r4)
 166         stbu    r0,-1(r6)
 167         bdnz    4b
 168         blr
 169 5:      mtctr   r0
 170 6:      lbzu    r7,-1(r4)
 171         stbu    r7,-1(r6)
 172         bdnz    6b
 173         subf    r5,r0,r5
 174         rlwinm. r7,r5,32-3,3,31
 175         beq     2b
 176         mtctr   r7
 177         b       1b
 178
 179 _GLOBAL(__copy_tofrom_user)
 180         addi    r4,r4,-4
 181         addi    r6,r3,-4
 182         neg     r0,r3
 183         andi.   r0,r0,CACHELINE_MASK    /* # bytes to start of cache line */
 184         beq     58f
 185
 186         cmplw   0,r5,r0                 /* is this more than total to do? */
 187         blt     63f                     /* if not much to do */
 188         andi.   r8,r0,3                 /* get it word-aligned first */
 189         mtctr   r8
 190         beq+    61f
 191 70:     lbz     r9,4(r4)                /* do some bytes */
 192 71:     stb     r9,4(r6)
 193         addi    r4,r4,1
 194         addi    r6,r6,1
 195         bdnz    70b
 196 61:     subf    r5,r0,r5
 197         srwi.   r0,r0,2
 198         mtctr   r0
 199         beq     58f
 200 72:     lwzu    r9,4(r4)                /* do some words */
 201 73:     stwu    r9,4(r6)
 202         bdnz    72b
 203
 204         .section __ex_table,"a"
 205         .align  2
 206         .long   70b,100f
 207         .long   71b,101f
 208         .long   72b,102f
 209         .long   73b,103f
 210         .text
 211
 212 58:     srwi.   r0,r5,LG_CACHELINE_BYTES /* # complete cachelines */
 213         clrlwi  r5,r5,32-LG_CACHELINE_BYTES
 214         li      r11,4
 215         beq     63f
 216
 217         /* Here we decide how far ahead to prefetch the source */
 218         li      r3,4
 219         cmpwi   r0,1
 220         li      r7,0
 221         ble     114f
 222         li      r7,1
 223 #if MAX_COPY_PREFETCH > 1
 224         /* Heuristically, for large transfers we prefetch
 225            MAX_COPY_PREFETCH cachelines ahead.  For small transfers
 226            we prefetch 1 cacheline ahead. */
 227         cmpwi   r0,MAX_COPY_PREFETCH
 228         ble     112f
 229         li      r7,MAX_COPY_PREFETCH
 230 112:    mtctr   r7
 231 111:    dcbt    r3,r4
 232         addi    r3,r3,CACHELINE_BYTES
 233         bdnz    111b
 234 #else
 235         dcbt    r3,r4
 236         addi    r3,r3,CACHELINE_BYTES
 237 #endif /* MAX_COPY_PREFETCH > 1 */
 238
 239 114:    subf    r8,r7,r0
 240         mr      r0,r7
 241         mtctr   r8
 242
 243 53:     dcbt    r3,r4
 244 54:     dcbz    r11,r6
 245         .section __ex_table,"a"
 246         .align  2
 247         .long   54b,105f
 248         .text
 249 /* the main body of the cacheline loop */
 250         COPY_16_BYTES_WITHEX(0)
 251 #if L1_CACHE_BYTES >= 32
 252         COPY_16_BYTES_WITHEX(1)
 253 #if L1_CACHE_BYTES >= 64
 254         COPY_16_BYTES_WITHEX(2)
 255         COPY_16_BYTES_WITHEX(3)
 256 #if L1_CACHE_BYTES >= 128
 257         COPY_16_BYTES_WITHEX(4)
 258         COPY_16_BYTES_WITHEX(5)
 259         COPY_16_BYTES_WITHEX(6)
 260         COPY_16_BYTES_WITHEX(7)
 261 #endif
 262 #endif
 263 #endif
 264         bdnz    53b
 265         cmpwi   r0,0
 266         li      r3,4
 267         li      r7,0
 268         bne     114b
 269
 270 63:     srwi.   r0,r5,2
 271         mtctr   r0
 272         beq     64f
 273 30:     lwzu    r0,4(r4)
 274 31:     stwu    r0,4(r6)
 275         bdnz    30b
 276
 277 64:     andi.   r0,r5,3
 278         mtctr   r0
 279         beq+    65f
 280 40:     lbz     r0,4(r4)
 281 41:     stb     r0,4(r6)
 282         addi    r4,r4,1
 283         addi    r6,r6,1
 284         bdnz    40b
 285 65:     li      r3,0
 286         blr
 287
 288 /* read fault, initial single-byte copy */
 289 100:    li      r9,0
 290         b       90f
 291 /* write fault, initial single-byte copy */
 292 101:    li      r9,1
 293 90:     subf    r5,r8,r5
 294         li      r3,0
 295         b       99f
 296 /* read fault, initial word copy */
 297 102:    li      r9,0
 298         b       91f
 299 /* write fault, initial word copy */
 300 103:    li      r9,1
 301 91:     li      r3,2
 302         b       99f
 303
 304 /*
 305  * this stuff handles faults in the cacheline loop and branches to either
 306  * 104f (if in read part) or 105f (if in write part), after updating r5
 307  */
 308         COPY_16_BYTES_EXCODE(0)
 309 #if L1_CACHE_BYTES >= 32
 310         COPY_16_BYTES_EXCODE(1)
 311 #if L1_CACHE_BYTES >= 64
 312         COPY_16_BYTES_EXCODE(2)
 313         COPY_16_BYTES_EXCODE(3)
 314 #if L1_CACHE_BYTES >= 128
 315         COPY_16_BYTES_EXCODE(4)
 316         COPY_16_BYTES_EXCODE(5)
 317         COPY_16_BYTES_EXCODE(6)
 318         COPY_16_BYTES_EXCODE(7)
 319 #endif
 320 #endif
 321 #endif
 322
 323 /* read fault in cacheline loop */
 324 104:    li      r9,0
 325         b       92f
 326 /* fault on dcbz (effectively a write fault) */
 327 /* or write fault in cacheline loop */
 328 105:    li      r9,1
 329 92:     li      r3,LG_CACHELINE_BYTES
 330         mfctr   r8
 331         add     r0,r0,r8
 332         b       106f
 333 /* read fault in final word loop */
 334 108:    li      r9,0
 335         b       93f
 336 /* write fault in final word loop */
 337 109:    li      r9,1
 338 93:     andi.   r5,r5,3
 339         li      r3,2
 340         b       99f
 341 /* read fault in final byte loop */
 342 110:    li      r9,0
 343         b       94f
 344 /* write fault in final byte loop */
 345 111:    li      r9,1
 346 94:     li      r5,0
 347         li      r3,0
 348 /*
 349  * At this stage the number of bytes not copied is
 350  * r5 + (ctr << r3), and r9 is 0 for read or 1 for write.
 351  */
 352 99:     mfctr   r0
 353 106:    slw     r3,r0,r3
 354         add.    r3,r3,r5
 355         beq     120f                    /* shouldn't happen */
 356         cmpwi   0,r9,0
 357         bne     120f
 358 /* for a read fault, first try to continue the copy one byte at a time */
 359         mtctr   r3
 360 130:    lbz     r0,4(r4)
 361 131:    stb     r0,4(r6)
 362         addi    r4,r4,1
 363         addi    r6,r6,1
 364         bdnz    130b
 365 /* then clear out the destination: r3 bytes starting at 4(r6) */
 366 132:    mfctr   r3
 367         srwi.   r0,r3,2
 368         li      r9,0
 369         mtctr   r0
 370         beq     113f
 371 112:    stwu    r9,4(r6)
 372         bdnz    112b
 373 113:    andi.   r0,r3,3
 374         mtctr   r0
 375         beq     120f
 376 114:    stb     r9,4(r6)
 377         addi    r6,r6,1
 378         bdnz    114b
 379 120:    blr
 380
 381         .section __ex_table,"a"
 382         .align  2
 383         .long   30b,108b
 384         .long   31b,109b
 385         .long   40b,110b
 386         .long   41b,111b
 387         .long   130b,132b
 388         .long   131b,120b
 389         .long   112b,120b
 390         .long   114b,120b
 391         .text