zlib 1.2.0.5v1.2.0.5

1 files changed, 408 insertions, 0 deletions

diff --git a/contrib/masm686/match.asm b/contrib/masm686/match.asm
new file mode 100644
index 00000000..2287804d
--- /dev/null
+++ b/contrib/masm686/match.asm
@@ -0,0 +1,408 @@
+
+; match.asm -- Pentium-Pro optimized version of longest_match()
+;
+; Updated for zlib 1.1.3 and converted to MASM 6.1x
+; Copyright (C) 2000 Dan Higdon <hdan@kinesoft.com>
+;                    and Chuck Walbourn <chuckw@kinesoft.com>
+; Corrections by Cosmin Truta <cosmint@cs.ubbcluj.ro>
+;
+; This is free software; you can redistribute it and/or modify it
+; under the terms of the GNU General Public License.
+
+; Based on match.S
+; Written for zlib 1.1.2
+; Copyright (C) 1998 Brian Raiter <breadbox@muppetlabs.com>
+
+        .686P
+        .MODEL  FLAT
+
+;===========================================================================
+; EQUATES
+;===========================================================================
+
+MAX_MATCH       EQU 258
+MIN_MATCH       EQU 3
+MIN_LOOKAHEAD   EQU (MAX_MATCH + MIN_MATCH + 1)
+MAX_MATCH_8     EQU ((MAX_MATCH + 7) AND (NOT 7))
+
+;===========================================================================
+; STRUCTURES
+;===========================================================================
+
+; This STRUCT assumes a 4-byte alignment
+
+DEFLATE_STATE   STRUCT
+ds_strm                 dd ?
+ds_status               dd ?
+ds_pending_buf          dd ?
+ds_pending_buf_size     dd ?
+ds_pending_out          dd ?
+ds_pending              dd ?
+ds_wrap                 dd ?
+ds_data_type            db ?
+ds_method               db ?
+                        db ?    ; padding
+                        db ?    ; padding
+ds_last_flush           dd ?
+ds_w_size               dd ?    ; used
+ds_w_bits               dd ?
+ds_w_mask               dd ?    ; used
+ds_window               dd ?    ; used
+ds_window_size          dd ?
+ds_prev                 dd ?    ; used
+ds_head                 dd ?
+ds_ins_h                dd ?
+ds_hash_size            dd ?
+ds_hash_bits            dd ?
+ds_hash_mask            dd ?
+ds_hash_shift           dd ?
+ds_block_start          dd ?
+ds_match_length         dd ?    ; used
+ds_prev_match           dd ?    ; used
+ds_match_available      dd ?
+ds_strstart             dd ?    ; used
+ds_match_start          dd ?    ; used
+ds_lookahead            dd ?    ; used
+ds_prev_length          dd ?    ; used
+ds_max_chain_length     dd ?    ; used
+ds_max_laxy_match       dd ?
+ds_level                dd ?
+ds_strategy             dd ?
+ds_good_match           dd ?    ; used
+ds_nice_match           dd ?    ; used
+
+; Don't need anymore of the struct for match
+DEFLATE_STATE   ENDS
+
+;===========================================================================
+; CODE
+;===========================================================================
+_TEXT   SEGMENT
+
+;---------------------------------------------------------------------------
+; match_init
+;---------------------------------------------------------------------------
+        ALIGN   4
+PUBLIC  _match_init
+_match_init     PROC
+        ; no initialization needed
+        ret
+_match_init     ENDP
+
+;---------------------------------------------------------------------------
+; uInt longest_match(deflate_state *deflatestate, IPos curmatch)
+;---------------------------------------------------------------------------
+        ALIGN   4
+
+PUBLIC  _longest_match
+_longest_match  PROC
+
+; Since this code uses EBP for a scratch register, the stack frame must
+; be manually constructed and referenced relative to the ESP register.
+
+; Stack image
+; Variables
+chainlenwmask   =  0    ; high word: current chain len
+                        ; low word: s->wmask
+window          =  4    ; local copy of s->window
+windowbestlen   =  8    ; s->window + bestlen
+scanend         = 12    ; last two bytes of string
+scanstart       = 16    ; first two bytes of string
+scanalign       = 20    ; dword-misalignment of string
+nicematch       = 24    ; a good enough match size
+bestlen         = 28    ; size of best match so far
+scan            = 32    ; ptr to string wanting match
+varsize         = 36    ; number of bytes (also offset to last saved register)
+
+; Saved Registers (actually pushed into place)
+ebx_save        = 36
+edi_save        = 40
+esi_save        = 44
+ebp_save        = 48
+
+; Parameters
+retaddr         = 52
+deflatestate    = 56
+curmatch        = 60
+
+; Save registers that the compiler may be using
+        push    ebp
+        push    edi
+        push    esi
+        push    ebx
+
+; Allocate local variable space
+        sub     esp,varsize
+
+; Retrieve the function arguments. ecx will hold cur_match
+; throughout the entire function. edx will hold the pointer to the
+; deflate_state structure during the function's setup (before
+; entering the main loop).
+
+        mov     edx, [esp+deflatestate]
+ASSUME  edx:PTR DEFLATE_STATE
+
+        mov     ecx, [esp+curmatch]
+
+; uInt wmask = s->w_mask;
+; unsigned chain_length = s->max_chain_length;
+; if (s->prev_length >= s->good_match) {
+;     chain_length >>= 2;
+; }
+
+        mov     eax, [edx].ds_prev_length
+        mov     ebx, [edx].ds_good_match
+        cmp     eax, ebx
+        mov     eax, [edx].ds_w_mask
+        mov     ebx, [edx].ds_max_chain_length
+        jl      SHORT LastMatchGood
+        shr     ebx, 2
+LastMatchGood:
+
+; chainlen is decremented once beforehand so that the function can
+; use the sign flag instead of the zero flag for the exit test.
+; It is then shifted into the high word, to make room for the wmask
+; value, which it will always accompany.
+
+        dec     ebx
+        shl     ebx, 16
+        or      ebx, eax
+        mov     [esp+chainlenwmask], ebx
+
+; if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead;
+
+        mov     eax, [edx].ds_nice_match
+        mov     ebx, [edx].ds_lookahead
+        cmp     ebx, eax
+        jl      SHORT LookaheadLess
+        mov     ebx, eax
+LookaheadLess:
+        mov     [esp+nicematch], ebx
+
+;/* register Bytef *scan = s->window + s->strstart;                     */
+
+        mov     esi, [edx].ds_window
+        mov     [esp+window], esi
+        mov     ebp, [edx].ds_strstart
+        lea     edi, [esi+ebp]
+        mov     [esp+scan],edi
+
+;/* Determine how many bytes the scan ptr is off from being             */
+;/* dword-aligned.                                                      */
+
+        mov     eax, edi
+        neg     eax
+        and     eax, 3
+        mov     [esp+scanalign], eax
+
+;/* IPos limit = s->strstart > (IPos)MAX_DIST(s) ?                      */
+;/*     s->strstart - (IPos)MAX_DIST(s) : NIL;                          */
+
+        mov     eax, [edx].ds_w_size
+        sub     eax, MIN_LOOKAHEAD
+        sub     ebp, eax
+        jg      SHORT LimitPositive
+        xor     ebp, ebp
+LimitPositive:
+
+;/* int best_len = s->prev_length;                                      */
+
+        mov     eax, [edx].ds_prev_length
+        mov     [esp+bestlen], eax
+
+;/* Store the sum of s->window + best_len in %esi locally, and in %esi. */
+
+        add     esi, eax
+        mov     [esp+windowbestlen], esi
+
+;/* register ush scan_start = *(ushf*)scan;                             */
+;/* register ush scan_end   = *(ushf*)(scan+best_len-1);                */
+;/* Posf *prev = s->prev;                                               */
+
+        movzx   ebx, WORD PTR[edi]
+        mov     [esp+scanstart], ebx
+        movzx   ebx, WORD PTR[eax+edi-1]
+        mov     [esp+scanend], ebx
+        mov     edi, [edx].ds_prev
+
+;/* Jump into the main loop.                                            */
+
+        mov     edx, [esp+chainlenwmask]
+        jmp     SHORT LoopEntry
+
+;/* do {
+; *     match = s->window + cur_match;
+; *     if (*(ushf*)(match+best_len-1) != scan_end ||
+; *         *(ushf*)match != scan_start) continue;
+; *     [...]
+; * } while ((cur_match = prev[cur_match & wmask]) > limit
+; *          && --chain_length != 0);
+; *
+; * Here is the inner loop of the function. The function will spend the
+; * majority of its time in this loop, and majority of that time will
+; * be spent in the first ten instructions.
+; *
+; * Within this loop:
+; * %ebx = scanend
+; * %ecx = curmatch
+; * %edx = chainlenwmask - i.e., ((chainlen << 16) | wmask)
+; * %esi = windowbestlen - i.e., (window + bestlen)
+; * %edi = prev
+; * %ebp = limit
+; */
+
+        ALIGN   4
+LookupLoop:
+        and     ecx, edx
+        movzx   ecx, WORD PTR[edi+ecx*2]
+        cmp     ecx, ebp
+        jbe     LeaveNow
+        sub     edx, 000010000H
+        js      LeaveNow
+
+LoopEntry:
+        movzx   eax, WORD PTR[esi+ecx-1]
+        cmp     eax, ebx
+        jnz     SHORT LookupLoop
+
+        mov     eax, [esp+window]
+        movzx   eax, WORD PTR[eax+ecx]
+        cmp     eax, [esp+scanstart]
+        jnz     SHORT LookupLoop
+
+;/* Store the current value of chainlen.                                */
+
+        mov     [esp+chainlenwmask], edx
+
+;/* Point %edi to the string under scrutiny, and %esi to the string we  */
+;/* are hoping to match it up with. In actuality, %esi and %edi are     */
+;/* both pointed (MAX_MATCH_8 - scanalign) bytes ahead, and %edx is     */
+;/* initialized to -(MAX_MATCH_8 - scanalign).                          */
+
+        mov     esi, [esp+window]
+        mov     edi, [esp+scan]
+        add     esi, ecx
+        mov     eax, [esp+scanalign]
+        mov     edx, -MAX_MATCH_8
+        lea     edi, [edi+eax+MAX_MATCH_8]
+        lea     esi, [esi+eax+MAX_MATCH_8]
+
+;/* Test the strings for equality, 8 bytes at a time. At the end,
+; * adjust %edx so that it is offset to the exact byte that mismatched.
+; *
+; * We already know at this point that the first three bytes of the
+; * strings match each other, and they can be safely passed over before
+; * starting the compare loop. So what this code does is skip over 0-3
+; * bytes, as much as necessary in order to dword-align the %edi
+; * pointer. (%esi will still be misaligned three times out of four.)
+; *
+; * It should be confessed that this loop usually does not represent
+; * much of the total running time. Replacing it with a more
+; * straightforward "rep cmpsb" would not drastically degrade
+; * performance.
+; */
+
+LoopCmps:
+        mov     eax, DWORD PTR[esi+edx]
+        xor     eax, DWORD PTR[edi+edx]
+        jnz     SHORT LeaveLoopCmps
+
+        mov     eax, DWORD PTR[esi+edx+4]
+        xor     eax, DWORD PTR[edi+edx+4]
+        jnz     SHORT LeaveLoopCmps4
+
+        add     edx, 8
+        jnz     SHORT LoopCmps
+        jmp     LenMaximum
+        ALIGN   4
+
+LeaveLoopCmps4:
+        add     edx, 4
+
+LeaveLoopCmps:
+        test    eax, 00000FFFFH
+        jnz     SHORT LenLower
+
+        add     edx, 2
+        shr     eax, 16
+
+LenLower:
+        sub     al, 1
+        adc     edx, 0
+
+;/* Calculate the length of the match. If it is longer than MAX_MATCH,  */
+;/* then automatically accept it as the best possible match and leave.  */
+
+        lea     eax, [edi+edx]
+        mov     edi, [esp+scan]
+        sub     eax, edi
+        cmp     eax, MAX_MATCH
+        jge     SHORT LenMaximum
+
+;/* If the length of the match is not longer than the best match we     */
+;/* have so far, then forget it and return to the lookup loop.          */
+
+        mov     edx, [esp+deflatestate]
+        mov     ebx, [esp+bestlen]
+        cmp     eax, ebx
+        jg      SHORT LongerMatch
+        mov     esi, [esp+windowbestlen]
+        mov     edi, [edx].ds_prev
+        mov     ebx, [esp+scanend]
+        mov     edx, [esp+chainlenwmask]
+        jmp     LookupLoop
+        ALIGN   4
+
+;/*         s->match_start = cur_match;                                 */
+;/*         best_len = len;                                             */
+;/*         if (len >= nice_match) break;                               */
+;/*         scan_end = *(ushf*)(scan+best_len-1);                       */
+
+LongerMatch:
+        mov     ebx, [esp+nicematch]
+        mov     [esp+bestlen], eax
+        mov     [edx].ds_match_start, ecx
+        cmp     eax, ebx
+        jge     SHORT LeaveNow
+        mov     esi, [esp+window]
+        add     esi, eax
+        mov     [esp+windowbestlen], esi
+        movzx   ebx, WORD PTR[edi+eax-1]
+        mov     edi, [edx].ds_prev
+        mov     [esp+scanend], ebx
+        mov     edx, [esp+chainlenwmask]
+        jmp     LookupLoop
+        ALIGN   4
+
+;/* Accept the current string, with the maximum possible length.        */
+
+LenMaximum:
+        mov     edx, [esp+deflatestate]
+        mov     DWORD PTR[esp+bestlen], MAX_MATCH
+        mov     [edx].ds_match_start, ecx
+
+;/* if ((uInt)best_len <= s->lookahead) return (uInt)best_len;          */
+;/* return s->lookahead;                                                */
+
+LeaveNow:
+        mov     edx, [esp+deflatestate]
+        mov     ebx, [esp+bestlen]
+        mov     eax, [edx].ds_lookahead
+        cmp     ebx, eax
+        jg      SHORT LookaheadRet
+        mov     eax, ebx
+LookaheadRet:
+
+; Restore the stack and return from whence we came.
+
+        add     esp, varsize
+        pop     ebx
+        pop     esi
+        pop     edi
+        pop     ebp
+        ret
+
+_longest_match  ENDP
+
+_TEXT   ENDS
+END