zlib 1.0.7

contrib/asm386/gvmat32c.c

@@ -0,0 +1,229 @@
+/* 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)
+ *
+ */
+//#pragma optimize("agt",on)
+
+#include "deflate.h"
+
+#undef FAR
+#include <windows.h>
+
+#ifdef ASMV
+
+#define NIL 0
+
+static unsigned int tot=0;
+static unsigned int totl0=0;
+static unsigned int totl0p0=0;
+static unsigned int ba0=0;
+static unsigned int ba1=0;
+static unsigned int cpta=0;
+static unsigned int cptb=0;
+
+#define UNALIGNED_OK
+#define gvshow(a,b,c,d)
+/*
+void gvshow(int chain_length,int len,int limit,ushf* prev)
+{
+static int ival=0;
+char sz[80];
+unsigned long i;
+int prev0=*prev;
+	ival++;
+	//wsprintf(sz,"call %u, len=%u, chain_length=%u\n",ival,len,chain_length);
+	//OutputDebugString(sz);
+	tot++;
+	if (limit==NIL)
+		totl0++;
+	if ((limit==NIL) && (prev0==0))
+		totl0p0++;
+	for (i=limit+1;i<32768;i++)
+	{
+		ush va=*(prev+i);
+		if (ba0>4000000000)
+		{
+			ba0+=10;
+		}
+		ba0++;
+		if ((va>limit) || (va==0))
+			continue;
+		ba1++;
+	}
+}
+*/
+
+
+/* if your C compiler don't add underline before function name,
+		define ADD_UNDERLINE_ASMFUNC */
+#ifdef ADD_UNDERLINE_ASMFUNC
+#define longest_match_asm7fff _longest_match_asm7fff
+#endif
+void match_init()
+{
+}
+
+uInt longest_match_c(
+    deflate_state *s,
+    IPos cur_match);                             /* current match */
+
+
+uInt longest_match_asm7fff(
+    deflate_state *s,
+    IPos cur_match);                             /* current match */
+
+uInt longest_match(
+    deflate_state *s,
+    IPos cur_match)                             /* current match */
+{
+    if (s->w_mask == 0x7fff)
+        return longest_match_asm7fff(s,cur_match);
+    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 best_len;
+    return s->lookahead;
+}
+
+#endif /* ASMV */