lib/match.c

   1 /* match.s -- optional optimized asm version of longest match in deflate.c
   2
   3    Copyright (C) 2002, 2006, 2009 Free Software Foundation, Inc.
   4    Copyright (C) 1992-1993 Jean-loup Gailly
   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 as published by
   8    the Free Software Foundation; either version 3, or (at your option)
   9    any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software Foundation,
  18    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
  19
  20 /*
  21  * The 68020 version has been written by Francesco Potorti` <pot@cnuce.cnr.it>
  22  * with adaptations by Carsten Steger <stegerc@informatik.tu-muenchen.de>,
  23  * Andreas Schwab <schwab@lamothe.informatik.uni-dortmund.de> and
  24  * Kristoffer Eriksson <ske@pkmab.se>
  25  *
  26  * The ia64 version has been written by Sverre Jarp (HP Labs) 2001-2002.
  27  * Unwind directives and some reformatting for better readability added by
  28  * David Mosberger-Tang <davidm@hpl.hp.com>.
  29  */
  30
  31 #include <config.h>
  32
  33 /* Preprocess with -DNO_UNDERLINE if your C compiler does not prefix
  34  * external symbols with an underline character '_'.
  35  */
  36 #ifdef NO_UNDERLINE
  37 #  define _prev             prev
  38 #  define _window           window
  39 #  define _match_start      match_start
  40 #  define _prev_length      prev_length
  41 #  define _good_match       good_match
  42 #  define _nice_match       nice_match
  43 #  define _strstart         strstart
  44 #  define _max_chain_length max_chain_length
  45
  46 #  define _match_init       match_init
  47 #  define _longest_match    longest_match
  48 #endif
  49
  50 #ifdef DYN_ALLOC
  51   error: DYN_ALLOC not yet supported in match.s
  52 #endif
  53
  54 #if defined(i386) || defined(_I386) || defined(__i386) || defined(__i386__)
  55
  56 /* This version is for 386 Unix or OS/2 in 32 bit mode.
  57  * Warning: it uses the AT&T syntax: mov source,dest
  58  * This file is only optional. If you want to force the C version,
  59  * add -DNO_ASM to CFLAGS in Makefile and set OBJA to an empty string.
  60  * If you have reduced WSIZE in gzip.h, then change its value below.
  61  * This version assumes static allocation of the arrays (-DDYN_ALLOC not used).
  62  */
  63
  64         .file   "match.S"
  65
  66 #define MAX_MATCH       258
  67 #define MAX_MATCH2      $128 /* MAX_MATCH/2-1 */
  68 #define MIN_MATCH       3
  69 #define    WSIZE        $32768
  70 #define MAX_DIST        WSIZE - MAX_MATCH - MIN_MATCH - 1
  71
  72         .globl  _match_init
  73         .globl  _longest_match
  74
  75         .text
  76
  77 _match_init:
  78         ret
  79
  80 /*-----------------------------------------------------------------------
  81  * Set match_start to the longest match starting at the given string and
  82  * return its length. Matches shorter or equal to prev_length are discarded,
  83  * in which case the result is equal to prev_length and match_start is
  84  * garbage.
  85  * IN assertions: cur_match is the head of the hash chain for the current
  86  *   string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
  87  */
  88
  89 _longest_match: /* int longest_match(cur_match) */
  90
  91 #define cur_match   20(%esp)
  92      /* return address */               /* esp+16 */
  93         push    %ebp                    /* esp+12 */
  94         push    %edi                    /* esp+8  */
  95         push    %esi                    /* esp+4  */
  96         push    %ebx                    /* esp    */
  97
  98 /*
  99  *      match        equ esi
 100  *      scan         equ edi
 101  *      chain_length equ ebp
 102  *      best_len     equ ebx
 103  *      limit        equ edx
 104  */
 105         mov     cur_match,%esi
 106         mov     _max_chain_length,%ebp /* chain_length = max_chain_length */
 107         mov     _strstart,%edi
 108         mov     %edi,%edx
 109         sub     MAX_DIST,%edx          /* limit = strstart-MAX_DIST */
 110         jae     limit_ok
 111         sub     %edx,%edx              /* limit = NIL */
 112 limit_ok:
 113         add     $2+_window,%edi        /* edi = offset(window+strstart+2) */
 114         mov     _prev_length,%ebx      /* best_len = prev_length */
 115         movw    -3(%ebx,%edi),%ax      /* ax = scan[best_len-1..best_len] */
 116         movw    -2(%edi),%cx           /* cx = scan[0..1] */
 117         cmp     _good_match,%ebx       /* do we have a good match already? */
 118         jb      do_scan
 119         shr     $2,%ebp                /* chain_length >>= 2 */
 120         jmp     do_scan
 121
 122         .align  4
 123 long_loop:
 124 /* at this point, edi == scan+2, esi == cur_match */
 125         movw    -3(%ebx,%edi),%ax       /* ax = scan[best_len-1..best_len] */
 126         movw     -2(%edi),%cx           /* cx = scan[0..1] */
 127 short_loop:
 128 /*
 129  * at this point, di == scan+2, si == cur_match,
 130  * ax = scan[best_len-1..best_len] and cx = scan[0..1]
 131  */
 132         and     WSIZE-1, %esi
 133         movw    _prev(%esi,%esi),%si    /* cur_match = prev[cur_match] */
 134                                         /* top word of esi is still 0 */
 135         cmp     %edx,%esi               /* cur_match <= limit ? */
 136         jbe     the_end
 137         dec     %ebp                    /* --chain_length */
 138         jz      the_end
 139 do_scan:
 140         cmpw    _window-1(%ebx,%esi),%ax/* check match at best_len-1 */
 141         jne     short_loop
 142         cmpw    _window(%esi),%cx       /* check min_match_length match */
 143         jne     short_loop
 144
 145         lea     _window+2(%esi),%esi    /* si = match */
 146         mov     %edi,%eax               /* ax = scan+2 */
 147         mov     MAX_MATCH2,%ecx         /* scan for at most MAX_MATCH bytes */
 148         rep;    cmpsw                   /* loop until mismatch */
 149         je      maxmatch                /* match of length MAX_MATCH? */
 150 mismatch:
 151         movb    -2(%edi),%cl        /* mismatch on first or second byte? */
 152         subb    -2(%esi),%cl        /* cl = 0 if first bytes equal */
 153         xchg    %edi,%eax           /* edi = scan+2, eax = end of scan */
 154         sub     %edi,%eax           /* eax = len */
 155         sub     %eax,%esi           /* esi = cur_match + 2 + offset(window) */
 156         sub     $2+_window,%esi     /* esi = cur_match */
 157         subb    $1,%cl              /* set carry if cl == 0 (cannot use DEC) */
 158         adc     $0,%eax             /* eax = carry ? len+1 : len */
 159         cmp     %ebx,%eax           /* len > best_len ? */
 160         jle     long_loop
 161         mov     %esi,_match_start       /* match_start = cur_match */
 162         mov     %eax,%ebx               /* ebx = best_len = len */
 163         cmp     _nice_match,%eax        /* len >= nice_match ? */
 164         jl      long_loop
 165 the_end:
 166         mov     %ebx,%eax               /* result = eax = best_len */
 167         pop     %ebx
 168         pop     %esi
 169         pop     %edi
 170         pop     %ebp
 171         ret
 172 maxmatch:
 173         cmpsb
 174         jmp     mismatch
 175
 176 #else
 177
 178 /* ======================== 680x0 version ================================= */
 179
 180 #if defined(m68k)||defined(mc68k)||defined(__mc68000__)||defined(__MC68000__)
 181 #  ifndef mc68000
 182 #    define mc68000
 183 #  endif
 184 #endif
 185
 186 #if defined(__mc68020__) || defined(__MC68020__) || defined(sysV68)
 187 #  ifndef mc68020
 188 #    define mc68020
 189 #  endif
 190 #endif
 191
 192 #if defined(mc68020) || defined(mc68000)
 193
 194 #if (defined(mc68020) || defined(NeXT)) && !defined(UNALIGNED_OK)
 195 #  define UNALIGNED_OK
 196 #endif
 197
 198 #ifdef sysV68  /* Try Motorola Delta style */
 199
 200 #  define GLOBAL(symbol)        global  symbol
 201 #  define TEXT                  text
 202 #  define FILE(filename)        file    filename
 203 #  define invert_maybe(src,dst) dst,src
 204 #  define imm(data)             &data
 205 #  define reg(register)         %register
 206
 207 #  define addl                  add.l
 208 #  define addql                 addq.l
 209 #  define blos                  blo.b
 210 #  define bhis                  bhi.b
 211 #  define bras                  bra.b
 212 #  define clrl                  clr.l
 213 #  define cmpmb                 cmpm.b
 214 #  define cmpw                  cmp.w
 215 #  define cmpl                  cmp.l
 216 #  define lslw                  lsl.w
 217 #  define lsrl                  lsr.l
 218 #  define movel                 move.l
 219 #  define movew                 move.w
 220 #  define moveb                 move.b
 221 #  define moveml                movem.l
 222 #  define subl                  sub.l
 223 #  define subw                  sub.w
 224 #  define subql                 subq.l
 225
 226 #  define IndBase(bd,An)        (bd,An)
 227 #  define IndBaseNdxl(bd,An,Xn) (bd,An,Xn.l)
 228 #  define IndBaseNdxw(bd,An,Xn) (bd,An,Xn.w)
 229 #  define predec(An)            -(An)
 230 #  define postinc(An)           (An)+
 231
 232 #else /* default style (Sun 3, NeXT, Amiga, Atari) */
 233
 234 #  define GLOBAL(symbol)        .globl  symbol
 235 #  define TEXT                  .text
 236 #  define FILE(filename)        .even
 237 #  define invert_maybe(src,dst) src,dst
 238 #  if defined(sun) || defined(mc68k)
 239 #    define imm(data)           #data
 240 #  else
 241 #    define imm(data)           \#data
 242 #  endif
 243 #  define reg(register)         register
 244
 245 #  define blos                  bcss
 246 #  if defined(sun) || defined(mc68k)
 247 #    define movel               movl
 248 #    define movew               movw
 249 #    define moveb               movb
 250 #  endif
 251 #  define IndBase(bd,An)        An@(bd)
 252 #  define IndBaseNdxl(bd,An,Xn) An@(bd,Xn:l)
 253 #  define IndBaseNdxw(bd,An,Xn) An@(bd,Xn:w)
 254 #  define predec(An)            An@-
 255 #  define postinc(An)           An@+
 256
 257 #endif  /* styles */
 258
 259 #define Best_Len        reg(d0)         /* unsigned */
 260 #define Cur_Match       reg(d1)         /* Ipos */
 261 #define Loop_Counter    reg(d2)         /* int */
 262 #define Scan_Start      reg(d3)         /* unsigned short */
 263 #define Scan_End        reg(d4)         /* unsigned short */
 264 #define Limit           reg(d5)         /* IPos */
 265 #define Chain_Length    reg(d6)         /* unsigned */
 266 #define Scan_Test       reg(d7)
 267 #define Scan            reg(a0)         /* *uch */
 268 #define Match           reg(a1)         /* *uch */
 269 #define Prev_Address    reg(a2)         /* *Pos */
 270 #define Scan_Ini        reg(a3)         /* *uch */
 271 #define Match_Ini       reg(a4)         /* *uch */
 272 #define Stack_Pointer   reg(sp)
 273
 274 #define MAX_MATCH       258
 275 #define MIN_MATCH       3
 276 #define WSIZE           32768
 277 #define MAX_DIST        (WSIZE - MAX_MATCH - MIN_MATCH - 1)
 278
 279         GLOBAL  (_match_init)
 280         GLOBAL  (_longest_match)
 281
 282         TEXT
 283
 284         FILE    ("match.S")
 285
 286 _match_init:
 287         rts
 288
 289 /*-----------------------------------------------------------------------
 290  * Set match_start to the longest match starting at the given string and
 291  * return its length. Matches shorter or equal to prev_length are discarded,
 292  * in which case the result is equal to prev_length and match_start is
 293  * garbage.
 294  * IN assertions: cur_match is the head of the hash chain for the current
 295  *   string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
 296  */
 297
 298 /* int longest_match (cur_match) */
 299
 300 #ifdef UNALIGNED_OK
 301 #  define pushreg       15928           /* d2-d6/a2-a4 */
 302 #  define popreg        7292
 303 #else
 304 #  define pushreg       16184           /* d2-d7/a2-a4 */
 305 #  define popreg        7420
 306 #endif
 307
 308 _longest_match:
 309         movel   IndBase(4,Stack_Pointer),Cur_Match
 310         moveml  imm(pushreg),predec(Stack_Pointer)
 311         movel   _max_chain_length,Chain_Length
 312         movel   _prev_length,Best_Len
 313         movel   imm(_prev),Prev_Address
 314         movel   imm(_window+MIN_MATCH),Match_Ini
 315         movel   _strstart,Limit
 316         movel   Match_Ini,Scan_Ini
 317         addl    Limit,Scan_Ini
 318         subw    imm(MAX_DIST),Limit
 319         bhis    L__limit_ok
 320         clrl    Limit
 321 L__limit_ok:
 322         cmpl    invert_maybe(_good_match,Best_Len)
 323         blos    L__length_ok
 324         lsrl    imm(2),Chain_Length
 325 L__length_ok:
 326         subql   imm(1),Chain_Length
 327 #ifdef UNALIGNED_OK
 328         movew   IndBase(-MIN_MATCH,Scan_Ini),Scan_Start
 329         movew   IndBaseNdxw(-MIN_MATCH-1,Scan_Ini,Best_Len),Scan_End
 330 #else
 331         moveb   IndBase(-MIN_MATCH,Scan_Ini),Scan_Start
 332         lslw    imm(8),Scan_Start
 333         moveb   IndBase(-MIN_MATCH+1,Scan_Ini),Scan_Start
 334         moveb   IndBaseNdxw(-MIN_MATCH-1,Scan_Ini,Best_Len),Scan_End
 335         lslw    imm(8),Scan_End
 336         moveb   IndBaseNdxw(-MIN_MATCH,Scan_Ini,Best_Len),Scan_End
 337 #endif
 338         bras    L__do_scan
 339
 340 L__long_loop:
 341 #ifdef UNALIGNED_OK
 342         movew   IndBaseNdxw(-MIN_MATCH-1,Scan_Ini,Best_Len),Scan_End
 343 #else
 344         moveb   IndBaseNdxw(-MIN_MATCH-1,Scan_Ini,Best_Len),Scan_End
 345         lslw    imm(8),Scan_End
 346         moveb   IndBaseNdxw(-MIN_MATCH,Scan_Ini,Best_Len),Scan_End
 347 #endif
 348
 349 L__short_loop:
 350         lslw    imm(1),Cur_Match
 351         movew   IndBaseNdxl(0,Prev_Address,Cur_Match),Cur_Match
 352         cmpw    invert_maybe(Limit,Cur_Match)
 353         dbls    Chain_Length,L__do_scan
 354         bras    L__return
 355
 356 L__do_scan:
 357         movel   Match_Ini,Match
 358         addl    Cur_Match,Match
 359 #ifdef UNALIGNED_OK
 360         cmpw    invert_maybe(IndBaseNdxw(-MIN_MATCH-1,Match,Best_Len),Scan_End)
 361         bne     L__short_loop
 362         cmpw    invert_maybe(IndBase(-MIN_MATCH,Match),Scan_Start)
 363         bne     L__short_loop
 364 #else
 365         moveb   IndBaseNdxw(-MIN_MATCH-1,Match,Best_Len),Scan_Test
 366         lslw    imm(8),Scan_Test
 367         moveb   IndBaseNdxw(-MIN_MATCH,Match,Best_Len),Scan_Test
 368         cmpw    invert_maybe(Scan_Test,Scan_End)
 369         bne     L__short_loop
 370         moveb   IndBase(-MIN_MATCH,Match),Scan_Test
 371         lslw    imm(8),Scan_Test
 372         moveb   IndBase(-MIN_MATCH+1,Match),Scan_Test
 373         cmpw    invert_maybe(Scan_Test,Scan_Start)
 374         bne     L__short_loop
 375 #endif
 376
 377         movew   imm((MAX_MATCH-MIN_MATCH+1)-1),Loop_Counter
 378         movel   Scan_Ini,Scan
 379 L__scan_loop:
 380         cmpmb   postinc(Match),postinc(Scan)
 381         dbne    Loop_Counter,L__scan_loop
 382
 383         subl    Scan_Ini,Scan
 384         addql   imm(MIN_MATCH-1),Scan
 385         cmpl    invert_maybe(Best_Len,Scan)
 386         bls     L__short_loop
 387         movel   Scan,Best_Len
 388         movel   Cur_Match,_match_start
 389         cmpl    invert_maybe(_nice_match,Best_Len)
 390         blos    L__long_loop
 391 L__return:
 392         moveml  postinc(Stack_Pointer),imm(popreg)
 393         rts
 394
 395 #else
 396
 397 # if defined (__ia64__)
 398
 399 /* ======================== ia64 version ================================= */
 400
 401 /*
 402  * 'longest_match.S' (assembly program for gzip for the IA-64 architecture)
 403  *
 404  * Optimised for McKinley, but with Merced-compatibility, such as MIB+MIB, used wherever
 405  * possible.
 406  *
 407  * Copyright: Sverre Jarp (HP Labs) 2001-2002
 408  *
 409  * See deflate.c for c-version
 410  * Version 2 - Optimize the outer loop
 411  */
 412
 413 #include <endian.h>
 414
 415 #if __BYTE_ORDER == ____BIG_ENDIAN
 416 #define  first  shl
 417 #define  second shr.u
 418 #define  count  czx1.l
 419 #else
 420 #define  first  shr.u
 421 #define  second shl
 422 #define  count  czx1.r
 423 #endif
 424
 425 // 24 rotating register (r32 - r55)
 426
 427 #define s_vmatch0               r32
 428 #define s_vmatch1               r33
 429 #define s_vmatbst               r34
 430 #define s_vmatbst1              r35
 431 #define s_amatblen              r36
 432
 433 #define s_tm1                   r56
 434 #define s_tm2                   r57
 435 #define s_tm3                   r58
 436 #define s_tm4                   r59
 437 #define s_tm5                   r60
 438 #define s_tm6                   r61
 439 #define s_tm7                   r62
 440 #define s_tm8                   r63
 441
 442 #define s_vlen                  r31
 443 #define s_vstrstart             r30
 444 #define s_vchainlen             r29
 445 #define s_awinbest              r28
 446 #define s_vcurmatch             r27
 447 #define s_vlimit                r26
 448 #define s_vscanend              r25
 449 #define s_vscanend1             r24
 450 #define s_anicematch            r23
 451 #define s_vscan0                r22
 452 #define s_vscan1                r21
 453
 454 #define s_aprev                 r20
 455 #define s_awindow               r19
 456 #define s_amatchstart           r18
 457 #define s_ascan                 r17
 458 #define s_amatch                r16
 459 #define s_wmask                 r15
 460 #define s_ascanend              r14
 461
 462 #define s_vspec_cmatch          r11             // next iteration
 463 #define s_lcsave                r10
 464 #define s_prsave                r9
 465 #define s_vbestlen              r8              // return register
 466
 467 #define s_vscan3                r3
 468 #define s_vmatch3               r2
 469
 470 #define p_no                    p2
 471 #define p_yes                   p3
 472 #define p_shf                   p4              //
 473 #define p_bn2                   p5              // Use in loop (indicating bestlen != 2)
 474
 475 #define p_nbs                   p9              // not new best_len
 476 #define p_nnc                   p10             // not nice_length
 477 #define p_ll                    p11
 478 #define p_end                   p12
 479
 480 #define MAX_MATCH               258
 481 #define MIN_MATCH                 4
 482 #define WSIZE                 32768
 483 #define MAX_DIST                WSIZE - MAX_MATCH - MIN_MATCH - 1
 484
 485 #define R_INPUT                 1
 486 #define R_LOCAL                 31
 487 #define R_OUTPUT                0
 488 #define R_ROTATING              24
 489 #define MLAT                    3
 490 #define SHLAT                   2
 491
 492 #define mova                    mov
 493 #define movi0                   mov
 494 #define cgtu                    cmp.gt.unc
 495 #define cgeu                    cmp.ge.unc
 496 #define cneu                    cmp.ne.unc
 497
 498         .global longest_match
 499         .proc longest_match
 500         .align 32
 501 longest_match:
 502 // --  Cycle: 0
 503         .prologue
 504 {.mmi
 505          alloc r2=ar.pfs,R_INPUT,R_LOCAL,R_OUTPUT,R_ROTATING
 506         .rotr scan[MLAT+2], match[MLAT+2], shscan0[SHLAT+1], \
 507               shscan1[SHLAT+1], shmatch0[SHLAT+1], shmatch1[SHLAT+1]
 508         .rotp lc[MLAT+SHLAT+2]
 509         mova s_vspec_cmatch=in0 // cur_match from input register
 510         add s_tm1=@gprel(strstart),gp // a(a(strstart))
 511 }{.mmi
 512         add s_tm3=@gprel(prev_length),gp // a(a(prev_length))
 513         add s_tm5=@ltoff(window),gp // a(a(window))
 514         add s_tm6=@ltoff(prev),gp // a(a(prev))
 515         ;;
 516 }{.mmb  //  Cycle: 1
 517         ld4 s_vstrstart=[s_tm1] // strstart
 518         ld4 s_vbestlen=[s_tm3] // best_len = prev_length
 519         brp.loop.imp .cmploop,.cmploop+48
 520 }{.mli
 521         add s_tm2=@gprel(max_chain_length),gp // a(a(max_chain_length))
 522         movl s_wmask=WSIZE-1
 523         ;;
 524 }{.mmi  //  Cycle: 2
 525         ld8 s_aprev=[s_tm6] // a(prev)
 526         ld8 s_awindow=[s_tm5] // a(window)
 527         .save pr, s_prsave
 528         movi0 s_prsave=pr // save predicates
 529 }{.mmi
 530         add s_tm4=@gprel(good_match),gp // a(a(good_match))
 531         add s_tm7=@ltoff(nice_match),gp // a(a(nice_match))
 532         add s_tm8=@ltoff(match_start),gp // a(match_start)
 533         ;;
 534 }{.mmi  //  Cycle: 3
 535         ld8 s_anicematch=[s_tm7] // a(nice_match)
 536         ld8 s_amatchstart=[s_tm8] // a(match_start)
 537         .save ar.lc, s_lcsave
 538         movi0 s_lcsave=ar.lc // save loop count register
 539 }{.mmi
 540         .body
 541         add s_tm1=-(MAX_MATCH + MIN_MATCH),s_wmask // maxdist
 542         cmp.eq p_ll,p0=r0,r0 // parallel compare initialized as 'true'
 543         mova s_vcurmatch=s_vspec_cmatch
 544         ;;
 545 }{.mmi  //  Cycle: 4
 546         ld4 s_vchainlen=[s_tm2] // chain_length=max_chain_length
 547         ld4 s_tm4=[s_tm4] // v(good_match)
 548         add s_ascan=s_awindow,s_vstrstart // scan=window + strstart
 549 }{.mmi
 550         sub s_vlimit=s_vstrstart, s_tm1 // limit=strstart - MAX_DIST
 551         add s_amatch=s_awindow,s_vspec_cmatch // match=window + cur_match
 552         and s_vspec_cmatch =s_vspec_cmatch,s_wmask
 553         ;;
 554 }{.mmi  //  Cycle: 5
 555         add s_amatblen=s_amatch,s_vbestlen //
 556         cneu p_bn2,p0=2,s_vbestlen // set if bestlen != 2
 557         add s_ascanend=s_ascan,s_vbestlen // compute a(scan) + best_len
 558 }{.mmi
 559         ld1 s_vscan0=[s_ascan],1 // NB: s_ascan++
 560         ld1 s_vmatch0=[s_amatch],1
 561         cgtu p0,p_no=s_vlimit,r0 // is result positive ?
 562         ;;
 563 }{.mmi  //  Cycle: 6
 564         ld1.nt1 s_vscan1=[s_ascan],2 // NB: s_ascan+3 in total
 565         ld1.nt1 s_vmatch1=[s_amatch],2
 566         add s_awinbest=s_awindow,s_vbestlen //
 567         ;;
 568 }{.mmi  //  Cycle: 7
 569         ld1.nt1 s_vscanend=[s_ascanend],-1 // scan_end=scan[best_len]
 570         ld1.nt1 s_vmatbst=[s_amatblen],-1
 571 (p_no)  mova s_vlimit=r0
 572         ;;
 573 }{.mmi  //  Cycle: 8
 574 (p_bn2) ld1.nt1 s_vscanend1=[s_ascanend],1 // scan_end1=scan[best_len-1]
 575 (p_bn2) ld1.nt1 s_vmatbst1=[s_amatblen]
 576         shladd s_vspec_cmatch =s_vspec_cmatch,1,s_aprev
 577 }{.mmi
 578         cgeu p_shf,p0=s_vbestlen,s_tm4 // is (prev_length >= good_match) ?
 579         ;;
 580 }{.mmi  //  Cycle: 9
 581         ld1.nt1 s_vscan3=[s_ascan]
 582         ld2.nt1 s_vspec_cmatch=[s_vspec_cmatch]
 583         mova    s_vlen=3
 584 }{.mmi
 585 (p_shf) shr.u s_vchainlen=s_vchainlen,2 // (cur_len) >> 2
 586         ;;
 587 }{.mmi  //  Cycle: 10
 588         ld1.nt1 s_vmatch3=[s_amatch]
 589         // p_ll switched on as soon as we get a mismatch:
 590         cmp.eq.and p_ll,p0=s_vmatch0,s_vscan0
 591         cmp.eq.and p_ll,p0=s_vmatbst,s_vscanend
 592 }{.mib
 593         cmp.eq.and p_ll,p0=s_vmatch1,s_vscan1
 594 (p_bn2) cmp.eq.and p_ll,p0=s_vmatbst1,s_vscanend1
 595 (p_ll)  br.cond.dpnt.many .test_more
 596         ;;
 597 }
 598
 599 .next_iter:
 600 {.mmi   // Cycle 0
 601         add s_amatch=s_awindow,s_vspec_cmatch   // match=window + cur_match
 602         mov s_vcurmatch=s_vspec_cmatch          // current value
 603         add s_vchainlen=-1,s_vchainlen          // --chain_length
 604 }{.mib
 605         cmp.le.unc p_end,p0=s_vspec_cmatch,s_vlimit
 606         and s_vspec_cmatch=s_vspec_cmatch,s_wmask
 607 (p_end) br.cond.dptk.many .terminate
 608         ;;
 609 }{.mmi  // Cycle 1
 610         ld1 s_vmatch0=[s_amatch],1              // load match[0]
 611         // compute prev[cur_match]:
 612         shladd s_vspec_cmatch=s_vspec_cmatch,1,s_aprev
 613         cmp.eq.unc p_end,p0=s_vchainlen,r0
 614 } {.mib
 615         nop.m 0
 616         add s_amatblen=s_awinbest,s_vcurmatch   // match=window + cur_match
 617 (p_end) br.cond.dptk.many .terminate
 618         ;;
 619 }{.mmi  // Cycle 2 (short)
 620         ld2.nt1 s_vspec_cmatch=[s_vspec_cmatch]         // get next cur_match
 621         ;;
 622 }{.mmi  // Cycle 3 (short)
 623         ld1.nt1 s_vmatbst=[s_amatblen],-1       // load match[best_len]
 624         cmp.ne.unc p_ll,p0=r0,r0     // parallel compare initialized as 'false'
 625         ;;
 626 }{.mmi  // Cycle 4 (short)
 627         // load match[1] - - note: match += 3 (in total):
 628         ld1.nt1 s_vmatch1=[s_amatch],2
 629         ;;
 630         // Cycle 5  (short)
 631 (p_bn2) ld1.nt1 s_vmatbst1=[s_amatblen]         // load match[best_len-1]
 632 }{.mib  // Here we (MOST LIKELY) pay a L2-fetch stall
 633         // p_ll switched on as soon as we get a mismatch:
 634         cmp.ne.or p_ll,p0=s_vmatch0,s_vscan0
 635         cmp.ne.or p_ll,p0=s_vmatbst,s_vscanend
 636 (p_ll)  br.cond.dptk.many .next_iter
 637         ;;
 638 }{.mmi  // Cycle 6
 639         ld1.nt1 s_vmatch3=[s_amatch]
 640         mova s_vlen=3
 641         nop.i 0
 642 }{.mib
 643         cmp.ne.or p_ll,p0=s_vmatch1,s_vscan1
 644 (p_bn2) cmp.ne.or p_ll,p0=s_vmatbst1,s_vscanend1
 645 (p_ll)  br.cond.dptk.many .next_iter
 646         ;;
 647 }
 648
 649 // We have passed the first hurdle - Are there additional matches ???
 650
 651 .test_more:
 652 {.mmi   // Cycle 0
 653         and s_tm3=7,s_ascan                     // get byte offset
 654         and s_tm4=7,s_amatch                    // get byte offset
 655         movi0 ar.ec=MLAT+SHLAT+2                // NB: One trip more than usual
 656 }{.mib
 657         cmp.ne.unc p_no,p0=s_vscan3,s_vmatch3   // does not next one differ?
 658 (p_no)  br.cond.dptk.many .only3
 659         ;;
 660 }{.mmi  // Cycle 1
 661         and s_tm1=-8,s_ascan    // get aligned address
 662         shladd s_tm3=s_tm3,3,r0
 663         movi0 ar.lc=31          // 32 times around the loop (8B at a time)
 664 }{.mib
 665         and s_tm2=-8,s_amatch                   // get aligned address
 666         shladd s_tm4=s_tm4,3,r0
 667         nop.b 0
 668         ;;
 669 }{.mmi  // Cycle 2
 670         ld8.nt1 scan[1]=[s_tm1],8                       // load first chunk
 671         sub s_tm5=64,s_tm3                              // 64 - amount
 672         movi0 pr.rot=1<<16
 673 }{.mmi
 674         ld8.nt1 match[1]=[s_tm2],8      // load first chunk
 675         sub s_tm6=64,s_tm4              // 64 - amount
 676         add s_vlen=-8,s_vlen            // will be updated at least once
 677         ;;
 678 }
 679         .align 32
 680 .cmploop:
 681 {.mmi   // Cycle 0
 682 (lc[0])                 ld8 scan[0]=[s_tm1],8           // next scan chunk
 683 (lc[MLAT+SHLAT+1])      add s_vlen=8,s_vlen
 684 (lc[MLAT])              first shscan0[0]=scan[MLAT+1],s_tm3
 685 }{.mib
 686 (lc[MLAT+SHLAT+1])      cmp.ne.unc p_no,p0=s_tm7,s_tm8  // break search if !=
 687 (lc[MLAT])              first shmatch0[0]=match[MLAT+1],s_tm4
 688 (p_no)                  br.cond.dpnt.many .mismatch
 689                         ;;
 690 }{.mii  // Cycle 1
 691 (lc[0])                 ld8 match[0]=[s_tm2],8
 692                         // shift left(le) or right(be):
 693 (lc[MLAT])              second shscan1[0]=scan[MLAT],s_tm5
 694 (lc[MLAT])              second shmatch1[0]=match[MLAT],s_tm6
 695 }{.mmb
 696 (lc[MLAT+SHLAT])        or s_tm7=shscan0[SHLAT],shscan1[SHLAT]
 697 (lc[MLAT+SHLAT])        or s_tm8=shmatch0[SHLAT],shmatch1[SHLAT]
 698                         br.ctop.dptk.many .cmploop
 699                         ;;
 700 }{.mfi
 701         mov s_vlen=258
 702         nop.f 0
 703 }{.mfi
 704         nop.f 0    // realign
 705         ;;
 706 }
 707 .mismatch:
 708 {.mii   // Cycle 0 (short)
 709 (p_no)  pcmp1.eq s_tm2=s_tm7,s_tm8      // find first non-matching character
 710         nop.i 0
 711         ;;
 712         // Cycle 1 (short)
 713 (p_no)  count s_tm1=s_tm2
 714         ;;
 715 }{.mib  // Cycle 2 (short)
 716 (p_no)  add s_vlen=s_vlen,s_tm1         // effective length
 717         nop.i 0
 718         clrrrb
 719         ;;
 720 }
 721
 722 .only3:
 723 {.mib   // Cycle 0 (short)
 724         cmp.gt.unc p0,p_nbs=s_vlen,s_vbestlen           // (len > best_len) ?
 725 (p_nbs) br.cond.dpnt.many .next_iter                    // if not, re-iternate
 726         ;;
 727 }{.mmi  // Cycle 1 (short)
 728         ld4 s_tm7=[s_anicematch]                        // nice_match
 729         st4 [s_amatchstart]= s_vcurmatch
 730         add s_ascanend=s_ascan,s_vlen                   // reset with best_len
 731         ;;
 732 }{.mmi  // Cycle 2 (short)
 733         mova s_vbestlen=s_vlen
 734         add s_ascanend=-3,s_ascanend            // remember extra offset
 735         ;;
 736 }{.mmi  // Cycle 3 (short)
 737         ld1 s_vscanend=[s_ascanend],-1          // scan_end=scan[best_len]
 738         add s_awinbest=s_awindow,s_vbestlen     // update with new best_len
 739         cmp.ne.unc p_bn2,p0=2,s_vbestlen        // set if bestlen != 2
 740         ;;
 741 }{.mib  // Cycle 4 (short)
 742         // scan_end1=scan[best_len-1] NB: s_ascanend reset:
 743         ld1.nt1 s_vscanend1=[s_ascanend],1
 744         cmp.lt.unc p_nnc,p0=s_vlen,s_tm7        // compare with nice_match
 745 (p_nnc) br.cond.dptk.many .next_iter
 746         ;;
 747 }
 748 .terminate:
 749 {.mii   // Cycle 0/1
 750         nop.m 0
 751         movi0 ar.lc=s_lcsave
 752         movi0 pr=s_prsave,-1
 753 }{.mbb
 754         nop.m 0
 755         nop.b 0
 756         br.ret.sptk.many rp     // ret0 is identical to best_len
 757         ;;
 758 }
 759         .endp
 760
 761         .global match_init
 762         .proc match_init
 763 match_init:
 764         sub ret0=ret0,ret0
 765         br.ret.sptk.many rp
 766         .endp
 767
 768 # else
 769  error: this asm version is for 386 or 680x0 or ia64 only
 770 # endif /* __ia64__ */
 771 #endif /* mc68000 || mc68020 */
 772 #endif /* i386 || _I386   */