+++ /dev/null
-/* gvmat32.c -- C portion of the optimized longest_match for 32 bits x86
- * Copyright (C) 1995-1996 Jean-loup Gailly and Gilles Vollant.
- * File written by Gilles Vollant, by modifiying the longest_match
- * from Jean-loup Gailly in deflate.c
- * it prepare all parameters and call the assembly longest_match_gvasm
- * longest_match execute standard C code is wmask != 0x7fff
- * (assembly code is faster with a fixed wmask)
- *
- */
-
-#include "deflate.h"
-
-#undef FAR
-#include <windows.h>
-
-#ifdef ASMV
-#define NIL 0
-
-#define UNALIGNED_OK
-
-
-/* if your C compiler don't add underline before function name,
- define ADD_UNDERLINE_ASMFUNC */
-#ifdef ADD_UNDERLINE_ASMFUNC
-#define longest_match_7fff _longest_match_7fff
-#endif
-
-
-
-void match_init()
-{
-}
-
-unsigned long cpudetect32();
-
-uInt longest_match_c(
- deflate_state *s,
- IPos cur_match); /* current match */
-
-
-uInt longest_match_7fff(
- deflate_state *s,
- IPos cur_match); /* current match */
-
-uInt longest_match(
- deflate_state *s,
- IPos cur_match) /* current match */
-{
- static uInt iIsPPro=2;
-
- if ((s->w_mask == 0x7fff) && (iIsPPro==0))
- return longest_match_7fff(s,cur_match);
-
- if (iIsPPro==2)
- iIsPPro = (((cpudetect32()/0x100)&0xf)>=6) ? 1 : 0;
-
- return longest_match_c(s,cur_match);
-}
-
-
-
-uInt longest_match_c(s, cur_match)
- deflate_state *s;
- IPos cur_match; /* current match */
-{
- unsigned chain_length = s->max_chain_length;/* max hash chain length */
- register Bytef *scan = s->window + s->strstart; /* current string */
- register Bytef *match; /* matched string */
- register int len; /* length of current match */
- int best_len = s->prev_length; /* best match length so far */
- int nice_match = s->nice_match; /* stop if match long enough */
- IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
- s->strstart - (IPos)MAX_DIST(s) : NIL;
- /* Stop when cur_match becomes <= limit. To simplify the code,
- * we prevent matches with the string of window index 0.
- */
- Posf *prev = s->prev;
- uInt wmask = s->w_mask;
-
-#ifdef UNALIGNED_OK
- /* Compare two bytes at a time. Note: this is not always beneficial.
- * Try with and without -DUNALIGNED_OK to check.
- */
- register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1;
- register ush scan_start = *(ushf*)scan;
- register ush scan_end = *(ushf*)(scan+best_len-1);
-#else
- register Bytef *strend = s->window + s->strstart + MAX_MATCH;
- register Byte scan_end1 = scan[best_len-1];
- register Byte scan_end = scan[best_len];
-#endif
-
- /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
- * It is easy to get rid of this optimization if necessary.
- */
- Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
-
- /* Do not waste too much time if we already have a good match: */
- if (s->prev_length >= s->good_match) {
- chain_length >>= 2;
- }
- /* Do not look for matches beyond the end of the input. This is necessary
- * to make deflate deterministic.
- */
- if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead;
-
- Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
-
- do {
- Assert(cur_match < s->strstart, "no future");
- match = s->window + cur_match;
-
- /* Skip to next match if the match length cannot increase
- * or if the match length is less than 2:
- */
-#if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
- /* This code assumes sizeof(unsigned short) == 2. Do not use
- * UNALIGNED_OK if your compiler uses a different size.
- */
- if (*(ushf*)(match+best_len-1) != scan_end ||
- *(ushf*)match != scan_start) continue;
-
- /* It is not necessary to compare scan[2] and match[2] since they are
- * always equal when the other bytes match, given that the hash keys
- * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at
- * strstart+3, +5, ... up to strstart+257. We check for insufficient
- * lookahead only every 4th comparison; the 128th check will be made
- * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is
- * necessary to put more guard bytes at the end of the window, or
- * to check more often for insufficient lookahead.
- */
- Assert(scan[2] == match[2], "scan[2]?");
- scan++, match++;
- do {
- } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
- *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
- *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
- *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
- scan < strend);
- /* The funny "do {}" generates better code on most compilers */
-
- /* Here, scan <= window+strstart+257 */
- Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
- if (*scan == *match) scan++;
-
- len = (MAX_MATCH - 1) - (int)(strend-scan);
- scan = strend - (MAX_MATCH-1);
-
-#else /* UNALIGNED_OK */
-
- if (match[best_len] != scan_end ||
- match[best_len-1] != scan_end1 ||
- *match != *scan ||
- *++match != scan[1]) continue;
-
- /* The check at best_len-1 can be removed because it will be made
- * again later. (This heuristic is not always a win.)
- * It is not necessary to compare scan[2] and match[2] since they
- * are always equal when the other bytes match, given that
- * the hash keys are equal and that HASH_BITS >= 8.
- */
- scan += 2, match++;
- Assert(*scan == *match, "match[2]?");
-
- /* We check for insufficient lookahead only every 8th comparison;
- * the 256th check will be made at strstart+258.
- */
- do {
- } while (*++scan == *++match && *++scan == *++match &&
- *++scan == *++match && *++scan == *++match &&
- *++scan == *++match && *++scan == *++match &&
- *++scan == *++match && *++scan == *++match &&
- scan < strend);
-
- Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
-
- len = MAX_MATCH - (int)(strend - scan);
- scan = strend - MAX_MATCH;
-
-#endif /* UNALIGNED_OK */
-
- if (len > best_len) {
- s->match_start = cur_match;
- best_len = len;
- if (len >= nice_match) break;
-#ifdef UNALIGNED_OK
- scan_end = *(ushf*)(scan+best_len-1);
-#else
- scan_end1 = scan[best_len-1];
- scan_end = scan[best_len];
-#endif
- }
- } while ((cur_match = prev[cur_match & wmask]) > limit
- && --chain_length != 0);
-
- if ((uInt)best_len <= s->lookahead) return (uInt)best_len;
- return s->lookahead;
-}
-
-#endif /* ASMV */
projects / msp430-gcc.git / blobdiff