drivers/video/fbdev/atafb_utils.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _VIDEO_ATAFB_UTILS_H
   3 #define _VIDEO_ATAFB_UTILS_H
   4
   5 /* ================================================================= */
   6 /*                      Utility Assembler Functions                  */
   7 /* ================================================================= */
   8
   9 /* ====================================================================== */
  10
  11 /* Those of a delicate disposition might like to skip the next couple of
  12  * pages.
  13  *
  14  * These functions are drop in replacements for memmove and
  15  * memset(_, 0, _). However their five instances add at least a kilobyte
  16  * to the object file. You have been warned.
  17  *
  18  * Not a great fan of assembler for the sake of it, but I think
  19  * that these routines are at least 10 times faster than their C
  20  * equivalents for large blits, and that's important to the lowest level of
  21  * a graphics driver. Question is whether some scheme with the blitter
  22  * would be faster. I suspect not for simple text system - not much
  23  * asynchrony.
  24  *
  25  * Code is very simple, just gruesome expansion. Basic strategy is to
  26  * increase data moved/cleared at each step to 16 bytes to reduce
  27  * instruction per data move overhead. movem might be faster still
  28  * For more than 15 bytes, we try to align the write direction on a
  29  * longword boundary to get maximum speed. This is even more gruesome.
  30  * Unaligned read/write used requires 68020+ - think this is a problem?
  31  *
  32  * Sorry!
  33  */
  34
  35
  36 /* ++roman: I've optimized Robert's original versions in some minor
  37  * aspects, e.g. moveq instead of movel, let gcc choose the registers,
  38  * use movem in some places...
  39  * For other modes than 1 plane, lots of more such assembler functions
  40  * were needed (e.g. the ones using movep or expanding color values).
  41  */
  42
  43 /* ++andreas: more optimizations:
  44    subl #65536,d0 replaced by clrw d0; subql #1,d0 for dbcc
  45    addal is faster than addaw
  46    movep is rather expensive compared to ordinary move's
  47    some functions rewritten in C for clarity, no speed loss */
  48
  49 static inline void *fb_memclear_small(void *s, size_t count)
  50 {
  51         if (!count)
  52                 return 0;
  53
  54         asm volatile ("\n"
  55                 "       lsr.l   #1,%1 ; jcc 1f ; move.b %2,-(%0)\n"
  56                 "1:     lsr.l   #1,%1 ; jcc 1f ; move.w %2,-(%0)\n"
  57                 "1:     lsr.l   #1,%1 ; jcc 1f ; move.l %2,-(%0)\n"
  58                 "1:     lsr.l   #1,%1 ; jcc 1f ; move.l %2,-(%0) ; move.l %2,-(%0)\n"
  59                 "1:"
  60                 : "=a" (s), "=d" (count)
  61                 : "d" (0), "0" ((char *)s + count), "1" (count));
  62         asm volatile ("\n"
  63                 "       subq.l  #1,%1\n"
  64                 "       jcs     3f\n"
  65                 "       move.l  %2,%%d4; move.l %2,%%d5; move.l %2,%%d6\n"
  66                 "2:     movem.l %2/%%d4/%%d5/%%d6,-(%0)\n"
  67                 "       dbra    %1,2b\n"
  68                 "3:"
  69                 : "=a" (s), "=d" (count)
  70                 : "d" (0), "0" (s), "1" (count)
  71                 : "d4", "d5", "d6"
  72                 );
  73
  74         return 0;
  75 }
  76
  77
  78 static inline void *fb_memclear(void *s, size_t count)
  79 {
  80         if (!count)
  81                 return 0;
  82
  83         if (count < 16) {
  84                 asm volatile ("\n"
  85                         "       lsr.l   #1,%1 ; jcc 1f ; clr.b (%0)+\n"
  86                         "1:     lsr.l   #1,%1 ; jcc 1f ; clr.w (%0)+\n"
  87                         "1:     lsr.l   #1,%1 ; jcc 1f ; clr.l (%0)+\n"
  88                         "1:     lsr.l   #1,%1 ; jcc 1f ; clr.l (%0)+ ; clr.l (%0)+\n"
  89                         "1:"
  90                         : "=a" (s), "=d" (count)
  91                         : "0" (s), "1" (count));
  92         } else {
  93                 long tmp;
  94                 asm volatile ("\n"
  95                         "       move.l  %1,%2\n"
  96                         "       lsr.l   #1,%2 ; jcc 1f ; clr.b (%0)+ ; subq.w #1,%1\n"
  97                         "       lsr.l   #1,%2 ; jcs 2f\n"  /* %0 increased=>bit 2 switched*/
  98                         "       clr.w   (%0)+  ; subq.w  #2,%1 ; jra 2f\n"
  99                         "1:     lsr.l   #1,%2 ; jcc 2f\n"
 100                         "       clr.w   (%0)+  ; subq.w  #2,%1\n"
 101                         "2:     move.w  %1,%2; lsr.l #2,%1 ; jeq 6f\n"
 102                         "       lsr.l   #1,%1 ; jcc 3f ; clr.l (%0)+\n"
 103                         "3:     lsr.l   #1,%1 ; jcc 4f ; clr.l (%0)+ ; clr.l (%0)+\n"
 104                         "4:     subq.l  #1,%1 ; jcs 6f\n"
 105                         "5:     clr.l   (%0)+; clr.l (%0)+ ; clr.l (%0)+ ; clr.l (%0)+\n"
 106                         "       dbra    %1,5b ; clr.w %1; subq.l #1,%1; jcc 5b\n"
 107                         "6:     move.w  %2,%1; btst #1,%1 ; jeq 7f ; clr.w (%0)+\n"
 108                         "7:     btst    #0,%1 ; jeq 8f ; clr.b (%0)+\n"
 109                         "8:"
 110                         : "=a" (s), "=d" (count), "=d" (tmp)
 111                         : "0" (s), "1" (count));
 112         }
 113
 114         return 0;
 115 }
 116
 117
 118 static inline void *fb_memset255(void *s, size_t count)
 119 {
 120         if (!count)
 121                 return 0;
 122
 123         asm volatile ("\n"
 124                 "       lsr.l   #1,%1 ; jcc 1f ; move.b %2,-(%0)\n"
 125                 "1:     lsr.l   #1,%1 ; jcc 1f ; move.w %2,-(%0)\n"
 126                 "1:     lsr.l   #1,%1 ; jcc 1f ; move.l %2,-(%0)\n"
 127                 "1:     lsr.l   #1,%1 ; jcc 1f ; move.l %2,-(%0) ; move.l %2,-(%0)\n"
 128                 "1:"
 129                 : "=a" (s), "=d" (count)
 130                 : "d" (-1), "0" ((char *)s+count), "1" (count));
 131         asm volatile ("\n"
 132                 "       subq.l  #1,%1 ; jcs 3f\n"
 133                 "       move.l  %2,%%d4; move.l %2,%%d5; move.l %2,%%d6\n"
 134                 "2:     movem.l %2/%%d4/%%d5/%%d6,-(%0)\n"
 135                 "       dbra    %1,2b\n"
 136                 "3:"
 137                 : "=a" (s), "=d" (count)
 138                 : "d" (-1), "0" (s), "1" (count)
 139                 : "d4", "d5", "d6");
 140
 141         return 0;
 142 }
 143
 144
 145 static inline void *fb_memmove(void *d, const void *s, size_t count)
 146 {
 147         if (d < s) {
 148                 if (count < 16) {
 149                         asm volatile ("\n"
 150                                 "       lsr.l   #1,%2 ; jcc 1f ; move.b (%1)+,(%0)+\n"
 151                                 "1:     lsr.l   #1,%2 ; jcc 1f ; move.w (%1)+,(%0)+\n"
 152                                 "1:     lsr.l   #1,%2 ; jcc 1f ; move.l (%1)+,(%0)+\n"
 153                                 "1:     lsr.l   #1,%2 ; jcc 1f ; move.l (%1)+,(%0)+ ; move.l (%1)+,(%0)+\n"
 154                                 "1:"
 155                                 : "=a" (d), "=a" (s), "=d" (count)
 156                                 : "0" (d), "1" (s), "2" (count));
 157                 } else {
 158                         long tmp;
 159                         asm volatile ("\n"
 160                                 "       move.l  %0,%3\n"
 161                                 "       lsr.l   #1,%3 ; jcc 1f ; move.b (%1)+,(%0)+ ; subqw #1,%2\n"
 162                                 "       lsr.l   #1,%3 ; jcs 2f\n"  /* %0 increased=>bit 2 switched*/
 163                                 "       move.w  (%1)+,(%0)+  ; subqw  #2,%2 ; jra 2f\n"
 164                                 "1:     lsr.l   #1,%3 ; jcc 2f\n"
 165                                 "       move.w  (%1)+,(%0)+  ; subqw  #2,%2\n"
 166                                 "2:     move.w  %2,%-; lsr.l #2,%2 ; jeq 6f\n"
 167                                 "       lsr.l   #1,%2 ; jcc 3f ; move.l (%1)+,(%0)+\n"
 168                                 "3:     lsr.l   #1,%2 ; jcc 4f ; move.l (%1)+,(%0)+ ; move.l (%1)+,(%0)+\n"
 169                                 "4:     subq.l  #1,%2 ; jcs 6f\n"
 170                                 "5:     move.l  (%1)+,(%0)+; move.l (%1)+,(%0)+\n"
 171                                 "       move.l  (%1)+,(%0)+; move.l (%1)+,(%0)+\n"
 172                                 "       dbra    %2,5b ; clr.w %2; subq.l #1,%2; jcc 5b\n"
 173                                 "6:     move.w  %+,%2; btst #1,%2 ; jeq 7f ; move.w (%1)+,(%0)+\n"
 174                                 "7:     btst    #0,%2 ; jeq 8f ; move.b (%1)+,(%0)+\n"
 175                                 "8:"
 176                                 : "=a" (d), "=a" (s), "=d" (count), "=d" (tmp)
 177                                 : "0" (d), "1" (s), "2" (count));
 178                 }
 179         } else {
 180                 if (count < 16) {
 181                         asm volatile ("\n"
 182                                 "       lsr.l   #1,%2 ; jcc 1f ; move.b -(%1),-(%0)\n"
 183                                 "1:     lsr.l   #1,%2 ; jcc 1f ; move.w -(%1),-(%0)\n"
 184                                 "1:     lsr.l   #1,%2 ; jcc 1f ; move.l -(%1),-(%0)\n"
 185                                 "1:     lsr.l   #1,%2 ; jcc 1f ; move.l -(%1),-(%0) ; move.l -(%1),-(%0)\n"
 186                                 "1:"
 187                                 : "=a" (d), "=a" (s), "=d" (count)
 188                                 : "0" ((char *) d + count), "1" ((char *) s + count), "2" (count));
 189                 } else {
 190                         long tmp;
 191
 192                         asm volatile ("\n"
 193                                 "       move.l  %0,%3\n"
 194                                 "       lsr.l   #1,%3 ; jcc 1f ; move.b -(%1),-(%0) ; subqw #1,%2\n"
 195                                 "       lsr.l   #1,%3 ; jcs 2f\n"  /* %0 increased=>bit 2 switched*/
 196                                 "       move.w  -(%1),-(%0) ; subqw  #2,%2 ; jra 2f\n"
 197                                 "1:     lsr.l   #1,%3 ; jcc 2f\n"
 198                                 "       move.w  -(%1),-(%0) ; subqw  #2,%2\n"
 199                                 "2:     move.w  %2,%-; lsr.l #2,%2 ; jeq 6f\n"
 200                                 "       lsr.l   #1,%2 ; jcc 3f ; move.l -(%1),-(%0)\n"
 201                                 "3:     lsr.l   #1,%2 ; jcc 4f ; move.l -(%1),-(%0) ; move.l -(%1),-(%0)\n"
 202                                 "4:     subq.l  #1,%2 ; jcs 6f\n"
 203                                 "5:     move.l  -(%1),-(%0); move.l -(%1),-(%0)\n"
 204                                 "       move.l  -(%1),-(%0); move.l -(%1),-(%0)\n"
 205                                 "       dbra    %2,5b ; clr.w %2; subq.l #1,%2; jcc 5b\n"
 206                                 "6:     move.w  %+,%2; btst #1,%2 ; jeq 7f ; move.w -(%1),-(%0)\n"
 207                                 "7:     btst    #0,%2 ; jeq 8f ; move.b -(%1),-(%0)\n"
 208                                 "8:"
 209                                 : "=a" (d), "=a" (s), "=d" (count), "=d" (tmp)
 210                                 : "0" ((char *) d + count), "1" ((char *) s + count), "2" (count));
 211                 }
 212         }
 213
 214         return 0;
 215 }
 216
 217
 218 /* ++andreas: Simple and fast version of memmove, assumes size is
 219    divisible by 16, suitable for moving the whole screen bitplane */
 220 static inline void fast_memmove(char *dst, const char *src, size_t size)
 221 {
 222         if (!size)
 223                 return;
 224         if (dst < src)
 225                 asm volatile ("\n"
 226                         "1:     movem.l (%0)+,%%d0/%%d1/%%a0/%%a1\n"
 227                         "       movem.l %%d0/%%d1/%%a0/%%a1,%1@\n"
 228                         "       addq.l  #8,%1; addq.l #8,%1\n"
 229                         "       dbra    %2,1b\n"
 230                         "       clr.w   %2; subq.l #1,%2\n"
 231                         "       jcc     1b"
 232                         : "=a" (src), "=a" (dst), "=d" (size)
 233                         : "0" (src), "1" (dst), "2" (size / 16 - 1)
 234                         : "d0", "d1", "a0", "a1", "memory");
 235         else
 236                 asm volatile ("\n"
 237                         "1:     subq.l  #8,%0; subq.l #8,%0\n"
 238                         "       movem.l %0@,%%d0/%%d1/%%a0/%%a1\n"
 239                         "       movem.l %%d0/%%d1/%%a0/%%a1,-(%1)\n"
 240                         "       dbra    %2,1b\n"
 241                         "       clr.w   %2; subq.l #1,%2\n"
 242                         "       jcc 1b"
 243                         : "=a" (src), "=a" (dst), "=d" (size)
 244                         : "0" (src + size), "1" (dst + size), "2" (size / 16 - 1)
 245                         : "d0", "d1", "a0", "a1", "memory");
 246 }
 247
 248 #ifdef BPL
 249
 250 /*
 251  * This expands a up to 8 bit color into two longs
 252  * for movel operations.
 253  */
 254 static const u32 four2long[] = {
 255         0x00000000, 0x000000ff, 0x0000ff00, 0x0000ffff,
 256         0x00ff0000, 0x00ff00ff, 0x00ffff00, 0x00ffffff,
 257         0xff000000, 0xff0000ff, 0xff00ff00, 0xff00ffff,
 258         0xffff0000, 0xffff00ff, 0xffffff00, 0xffffffff,
 259 };
 260
 261 static inline void expand8_col2mask(u8 c, u32 m[])
 262 {
 263         m[0] = four2long[c & 15];
 264 #if BPL > 4
 265         m[1] = four2long[c >> 4];
 266 #endif
 267 }
 268
 269 static inline void expand8_2col2mask(u8 fg, u8 bg, u32 fgm[], u32 bgm[])
 270 {
 271         fgm[0] = four2long[fg & 15] ^ (bgm[0] = four2long[bg & 15]);
 272 #if BPL > 4
 273         fgm[1] = four2long[fg >> 4] ^ (bgm[1] = four2long[bg >> 4]);
 274 #endif
 275 }
 276
 277 /*
 278  * set an 8bit value to a color
 279  */
 280 static inline void fill8_col(u8 *dst, u32 m[])
 281 {
 282         u32 tmp = m[0];
 283         dst[0] = tmp;
 284         dst[2] = (tmp >>= 8);
 285 #if BPL > 2
 286         dst[4] = (tmp >>= 8);
 287         dst[6] = tmp >> 8;
 288 #endif
 289 #if BPL > 4
 290         tmp = m[1];
 291         dst[8] = tmp;
 292         dst[10] = (tmp >>= 8);
 293         dst[12] = (tmp >>= 8);
 294         dst[14] = tmp >> 8;
 295 #endif
 296 }
 297
 298 /*
 299  * set an 8bit value according to foreground/background color
 300  */
 301 static inline void fill8_2col(u8 *dst, u8 fg, u8 bg, u32 mask)
 302 {
 303         u32 fgm[2], bgm[2], tmp;
 304
 305         expand8_2col2mask(fg, bg, fgm, bgm);
 306
 307         mask |= mask << 8;
 308 #if BPL > 2
 309         mask |= mask << 16;
 310 #endif
 311         tmp = (mask & fgm[0]) ^ bgm[0];
 312         dst[0] = tmp;
 313         dst[2] = (tmp >>= 8);
 314 #if BPL > 2
 315         dst[4] = (tmp >>= 8);
 316         dst[6] = tmp >> 8;
 317 #endif
 318 #if BPL > 4
 319         tmp = (mask & fgm[1]) ^ bgm[1];
 320         dst[8] = tmp;
 321         dst[10] = (tmp >>= 8);
 322         dst[12] = (tmp >>= 8);
 323         dst[14] = tmp >> 8;
 324 #endif
 325 }
 326
 327 static const u32 two2word[] = {
 328         0x00000000, 0xffff0000, 0x0000ffff, 0xffffffff
 329 };
 330
 331 static inline void expand16_col2mask(u8 c, u32 m[])
 332 {
 333         m[0] = two2word[c & 3];
 334 #if BPL > 2
 335         m[1] = two2word[(c >> 2) & 3];
 336 #endif
 337 #if BPL > 4
 338         m[2] = two2word[(c >> 4) & 3];
 339         m[3] = two2word[c >> 6];
 340 #endif
 341 }
 342
 343 static inline void expand16_2col2mask(u8 fg, u8 bg, u32 fgm[], u32 bgm[])
 344 {
 345         bgm[0] = two2word[bg & 3];
 346         fgm[0] = two2word[fg & 3] ^ bgm[0];
 347 #if BPL > 2
 348         bgm[1] = two2word[(bg >> 2) & 3];
 349         fgm[1] = two2word[(fg >> 2) & 3] ^ bgm[1];
 350 #endif
 351 #if BPL > 4
 352         bgm[2] = two2word[(bg >> 4) & 3];
 353         fgm[2] = two2word[(fg >> 4) & 3] ^ bgm[2];
 354         bgm[3] = two2word[bg >> 6];
 355         fgm[3] = two2word[fg >> 6] ^ bgm[3];
 356 #endif
 357 }
 358
 359 static inline u32 *fill16_col(u32 *dst, int rows, u32 m[])
 360 {
 361         while (rows) {
 362                 *dst++ = m[0];
 363 #if BPL > 2
 364                 *dst++ = m[1];
 365 #endif
 366 #if BPL > 4
 367                 *dst++ = m[2];
 368                 *dst++ = m[3];
 369 #endif
 370                 rows--;
 371         }
 372         return dst;
 373 }
 374
 375 static inline void memmove32_col(void *dst, void *src, u32 mask, u32 h, u32 bytes)
 376 {
 377         u32 *s, *d, v;
 378
 379         s = src;
 380         d = dst;
 381         do {
 382                 v = (*s++ & mask) | (*d  & ~mask);
 383                 *d++ = v;
 384 #if BPL > 2
 385                 v = (*s++ & mask) | (*d  & ~mask);
 386                 *d++ = v;
 387 #endif
 388 #if BPL > 4
 389                 v = (*s++ & mask) | (*d  & ~mask);
 390                 *d++ = v;
 391                 v = (*s++ & mask) | (*d  & ~mask);
 392                 *d++ = v;
 393 #endif
 394                 d = (u32 *)((u8 *)d + bytes);
 395                 s = (u32 *)((u8 *)s + bytes);
 396         } while (--h);
 397 }
 398
 399 #endif
 400
 401 #endif /* _VIDEO_ATAFB_UTILS_H */