summaryrefslogtreecommitdiffstats
path: root/cpukit/zlib/contrib/masm686/match.asm
diff options
context:
space:
mode:
Diffstat (limited to 'cpukit/zlib/contrib/masm686/match.asm')
-rw-r--r--cpukit/zlib/contrib/masm686/match.asm821
1 files changed, 413 insertions, 408 deletions
diff --git a/cpukit/zlib/contrib/masm686/match.asm b/cpukit/zlib/contrib/masm686/match.asm
index 2287804d44..4b03a71abd 100644
--- a/cpukit/zlib/contrib/masm686/match.asm
+++ b/cpukit/zlib/contrib/masm686/match.asm
@@ -1,408 +1,413 @@
-
-; 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
+
+; 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>
+;
+; Modified by Gilles Vollant (2005) for add gzhead and gzindex
+
+ .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 ?
+; gzhead and gzindex are added in zlib 1.2.2.2 (see deflate.h)
+ds_gzhead dd ?
+ds_gzindex 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
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-08 10:55:17 +0000