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author | jan.nijtmans <jan.nijtmans@noemail.net> | 2012-05-04 21:11:58 (GMT) |
---|---|---|
committer | jan.nijtmans <jan.nijtmans@noemail.net> | 2012-05-04 21:11:58 (GMT) |
commit | f1472e313401bcc589f60774b27216f99ced8c68 (patch) | |
tree | 5c2d242d388629c51debe71a52c47c2625303522 /compat | |
parent | 2ff8b627af4afa8aebc450458196c31a97e8fbab (diff) | |
download | tcl-f1472e313401bcc589f60774b27216f99ced8c68.zip tcl-f1472e313401bcc589f60774b27216f99ced8c68.tar.gz tcl-f1472e313401bcc589f60774b27216f99ced8c68.tar.bz2 |
some more removals from zlib1.2.7
FossilOrigin-Name: 0b062cab344e81e3deba45c6f85ea21fb56e0aa9
Diffstat (limited to 'compat')
-rw-r--r-- | compat/zlib/contrib/asm586/README.586 | 43 | ||||
-rw-r--r-- | compat/zlib/contrib/asm586/match.S | 364 | ||||
-rw-r--r-- | compat/zlib/contrib/masm686/match.asm | 413 |
3 files changed, 0 insertions, 820 deletions
diff --git a/compat/zlib/contrib/asm586/README.586 b/compat/zlib/contrib/asm586/README.586 deleted file mode 100644 index 6bb78f3..0000000 --- a/compat/zlib/contrib/asm586/README.586 +++ /dev/null @@ -1,43 +0,0 @@ -This is a patched version of zlib modified to use -Pentium-optimized assembly code in the deflation algorithm. The files -changed/added by this patch are: - -README.586 -match.S - -The effectiveness of these modifications is a bit marginal, as the the -program's bottleneck seems to be mostly L1-cache contention, for which -there is no real way to work around without rewriting the basic -algorithm. The speedup on average is around 5-10% (which is generally -less than the amount of variance between subsequent executions). -However, when used at level 9 compression, the cache contention can -drop enough for the assembly version to achieve 10-20% speedup (and -sometimes more, depending on the amount of overall redundancy in the -files). Even here, though, cache contention can still be the limiting -factor, depending on the nature of the program using the zlib library. -This may also mean that better improvements will be seen on a Pentium -with MMX, which suffers much less from L1-cache contention, but I have -not yet verified this. - -Note that this code has been tailored for the Pentium in particular, -and will not perform well on the Pentium Pro (due to the use of a -partial register in the inner loop). - -If you are using an assembler other than GNU as, you will have to -translate match.S to use your assembler's syntax. (Have fun.) - -Brian Raiter -breadbox@muppetlabs.com -April, 1998 - - -Added for zlib 1.1.3: - -The patches come from -http://www.muppetlabs.com/~breadbox/software/assembly.html - -To compile zlib with this asm file, copy match.S to the zlib directory -then do: - -CFLAGS="-O3 -DASMV" ./configure -make OBJA=match.o diff --git a/compat/zlib/contrib/asm586/match.S b/compat/zlib/contrib/asm586/match.S deleted file mode 100644 index 0368b35..0000000 --- a/compat/zlib/contrib/asm586/match.S +++ /dev/null @@ -1,364 +0,0 @@ -/* match.s -- Pentium-optimized version of longest_match() - * Written for zlib 1.1.2 - * Copyright (C) 1998 Brian Raiter <breadbox@muppetlabs.com> - * - * This is free software; you can redistribute it and/or modify it - * under the terms of the GNU General Public License. - */ - -#ifndef NO_UNDERLINE -#define match_init _match_init -#define longest_match _longest_match -#endif - -#define MAX_MATCH (258) -#define MIN_MATCH (3) -#define MIN_LOOKAHEAD (MAX_MATCH + MIN_MATCH + 1) -#define MAX_MATCH_8 ((MAX_MATCH + 7) & ~7) - -/* stack frame offsets */ - -#define wmask 0 /* local copy of s->wmask */ -#define window 4 /* local copy of s->window */ -#define windowbestlen 8 /* s->window + bestlen */ -#define chainlenscanend 12 /* high word: current chain len */ - /* low word: last bytes sought */ -#define scanstart 16 /* first two bytes of string */ -#define scanalign 20 /* dword-misalignment of string */ -#define nicematch 24 /* a good enough match size */ -#define bestlen 28 /* size of best match so far */ -#define scan 32 /* ptr to string wanting match */ - -#define LocalVarsSize (36) -/* saved ebx 36 */ -/* saved edi 40 */ -/* saved esi 44 */ -/* saved ebp 48 */ -/* return address 52 */ -#define deflatestate 56 /* the function arguments */ -#define curmatch 60 - -/* Offsets for fields in the deflate_state structure. These numbers - * are calculated from the definition of deflate_state, with the - * assumption that the compiler will dword-align the fields. (Thus, - * changing the definition of deflate_state could easily cause this - * program to crash horribly, without so much as a warning at - * compile time. Sigh.) - */ - -/* All the +zlib1222add offsets are due to the addition of fields - * in zlib in the deflate_state structure since the asm code was first written - * (if you compile with zlib 1.0.4 or older, use "zlib1222add equ (-4)"). - * (if you compile with zlib between 1.0.5 and 1.2.2.1, use "zlib1222add equ 0"). - * if you compile with zlib 1.2.2.2 or later , use "zlib1222add equ 8"). - */ - -#define zlib1222add (8) - -#define dsWSize (36+zlib1222add) -#define dsWMask (44+zlib1222add) -#define dsWindow (48+zlib1222add) -#define dsPrev (56+zlib1222add) -#define dsMatchLen (88+zlib1222add) -#define dsPrevMatch (92+zlib1222add) -#define dsStrStart (100+zlib1222add) -#define dsMatchStart (104+zlib1222add) -#define dsLookahead (108+zlib1222add) -#define dsPrevLen (112+zlib1222add) -#define dsMaxChainLen (116+zlib1222add) -#define dsGoodMatch (132+zlib1222add) -#define dsNiceMatch (136+zlib1222add) - - -.file "match.S" - -.globl match_init, longest_match - -.text - -/* uInt longest_match(deflate_state *deflatestate, IPos curmatch) */ - -longest_match: - -/* Save registers that the compiler may be using, and adjust %esp to */ -/* make room for our stack frame. */ - - pushl %ebp - pushl %edi - pushl %esi - pushl %ebx - subl $LocalVarsSize, %esp - -/* 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). */ - - movl deflatestate(%esp), %edx - movl curmatch(%esp), %ecx - -/* if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead; */ - - movl dsNiceMatch(%edx), %eax - movl dsLookahead(%edx), %ebx - cmpl %eax, %ebx - jl LookaheadLess - movl %eax, %ebx -LookaheadLess: movl %ebx, nicematch(%esp) - -/* register Bytef *scan = s->window + s->strstart; */ - - movl dsWindow(%edx), %esi - movl %esi, window(%esp) - movl dsStrStart(%edx), %ebp - lea (%esi,%ebp), %edi - movl %edi, scan(%esp) - -/* Determine how many bytes the scan ptr is off from being */ -/* dword-aligned. */ - - movl %edi, %eax - negl %eax - andl $3, %eax - movl %eax, scanalign(%esp) - -/* IPos limit = s->strstart > (IPos)MAX_DIST(s) ? */ -/* s->strstart - (IPos)MAX_DIST(s) : NIL; */ - - movl dsWSize(%edx), %eax - subl $MIN_LOOKAHEAD, %eax - subl %eax, %ebp - jg LimitPositive - xorl %ebp, %ebp -LimitPositive: - -/* unsigned chain_length = s->max_chain_length; */ -/* if (s->prev_length >= s->good_match) { */ -/* chain_length >>= 2; */ -/* } */ - - movl dsPrevLen(%edx), %eax - movl dsGoodMatch(%edx), %ebx - cmpl %ebx, %eax - movl dsMaxChainLen(%edx), %ebx - jl LastMatchGood - shrl $2, %ebx -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 scanend */ -/* scanend value, which it will always accompany. */ - - decl %ebx - shll $16, %ebx - -/* int best_len = s->prev_length; */ - - movl dsPrevLen(%edx), %eax - movl %eax, bestlen(%esp) - -/* Store the sum of s->window + best_len in %esi locally, and in %esi. */ - - addl %eax, %esi - movl %esi, windowbestlen(%esp) - -/* register ush scan_start = *(ushf*)scan; */ -/* register ush scan_end = *(ushf*)(scan+best_len-1); */ - - movw (%edi), %bx - movw %bx, scanstart(%esp) - movw -1(%edi,%eax), %bx - movl %ebx, chainlenscanend(%esp) - -/* Posf *prev = s->prev; */ -/* uInt wmask = s->w_mask; */ - - movl dsPrev(%edx), %edi - movl dsWMask(%edx), %edx - mov %edx, wmask(%esp) - -/* Jump into the main loop. */ - - jmp LoopEntry - -.balign 16 - -/* 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 = chainlenscanend - i.e., ((chainlen << 16) | scanend) - * %ecx = curmatch - * %edx = curmatch & wmask - * %esi = windowbestlen - i.e., (window + bestlen) - * %edi = prev - * %ebp = limit - * - * Two optimization notes on the choice of instructions: - * - * The first instruction uses a 16-bit address, which costs an extra, - * unpairable cycle. This is cheaper than doing a 32-bit access and - * zeroing the high word, due to the 3-cycle misalignment penalty which - * would occur half the time. This also turns out to be cheaper than - * doing two separate 8-bit accesses, as the memory is so rarely in the - * L1 cache. - * - * The window buffer, however, apparently spends a lot of time in the - * cache, and so it is faster to retrieve the word at the end of the - * match string with two 8-bit loads. The instructions that test the - * word at the beginning of the match string, however, are executed - * much less frequently, and there it was cheaper to use 16-bit - * instructions, which avoided the necessity of saving off and - * subsequently reloading one of the other registers. - */ -LookupLoop: - /* 1 U & V */ - movw (%edi,%edx,2), %cx /* 2 U pipe */ - movl wmask(%esp), %edx /* 2 V pipe */ - cmpl %ebp, %ecx /* 3 U pipe */ - jbe LeaveNow /* 3 V pipe */ - subl $0x00010000, %ebx /* 4 U pipe */ - js LeaveNow /* 4 V pipe */ -LoopEntry: movb -1(%esi,%ecx), %al /* 5 U pipe */ - andl %ecx, %edx /* 5 V pipe */ - cmpb %bl, %al /* 6 U pipe */ - jnz LookupLoop /* 6 V pipe */ - movb (%esi,%ecx), %ah - cmpb %bh, %ah - jnz LookupLoop - movl window(%esp), %eax - movw (%eax,%ecx), %ax - cmpw scanstart(%esp), %ax - jnz LookupLoop - -/* Store the current value of chainlen. */ - - movl %ebx, chainlenscanend(%esp) - -/* 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). */ - - movl window(%esp), %esi - movl scan(%esp), %edi - addl %ecx, %esi - movl scanalign(%esp), %eax - movl $(-MAX_MATCH_8), %edx - lea MAX_MATCH_8(%edi,%eax), %edi - lea MAX_MATCH_8(%esi,%eax), %esi - -/* 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: - movl (%esi,%edx), %eax - movl (%edi,%edx), %ebx - xorl %ebx, %eax - jnz LeaveLoopCmps - movl 4(%esi,%edx), %eax - movl 4(%edi,%edx), %ebx - xorl %ebx, %eax - jnz LeaveLoopCmps4 - addl $8, %edx - jnz LoopCmps - jmp LenMaximum -LeaveLoopCmps4: addl $4, %edx -LeaveLoopCmps: testl $0x0000FFFF, %eax - jnz LenLower - addl $2, %edx - shrl $16, %eax -LenLower: subb $1, %al - adcl $0, %edx - -/* 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 (%edi,%edx), %eax - movl scan(%esp), %edi - subl %edi, %eax - cmpl $MAX_MATCH, %eax - jge 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. */ - - movl deflatestate(%esp), %edx - movl bestlen(%esp), %ebx - cmpl %ebx, %eax - jg LongerMatch - movl chainlenscanend(%esp), %ebx - movl windowbestlen(%esp), %esi - movl dsPrev(%edx), %edi - movl wmask(%esp), %edx - andl %ecx, %edx - jmp LookupLoop - -/* s->match_start = cur_match; */ -/* best_len = len; */ -/* if (len >= nice_match) break; */ -/* scan_end = *(ushf*)(scan+best_len-1); */ - -LongerMatch: movl nicematch(%esp), %ebx - movl %eax, bestlen(%esp) - movl %ecx, dsMatchStart(%edx) - cmpl %ebx, %eax - jge LeaveNow - movl window(%esp), %esi - addl %eax, %esi - movl %esi, windowbestlen(%esp) - movl chainlenscanend(%esp), %ebx - movw -1(%edi,%eax), %bx - movl dsPrev(%edx), %edi - movl %ebx, chainlenscanend(%esp) - movl wmask(%esp), %edx - andl %ecx, %edx - jmp LookupLoop - -/* Accept the current string, with the maximum possible length. */ - -LenMaximum: movl deflatestate(%esp), %edx - movl $MAX_MATCH, bestlen(%esp) - movl %ecx, dsMatchStart(%edx) - -/* if ((uInt)best_len <= s->lookahead) return (uInt)best_len; */ -/* return s->lookahead; */ - -LeaveNow: - movl deflatestate(%esp), %edx - movl bestlen(%esp), %ebx - movl dsLookahead(%edx), %eax - cmpl %eax, %ebx - jg LookaheadRet - movl %ebx, %eax -LookaheadRet: - -/* Restore the stack and return from whence we came. */ - - addl $LocalVarsSize, %esp - popl %ebx - popl %esi - popl %edi - popl %ebp -match_init: ret diff --git a/compat/zlib/contrib/masm686/match.asm b/compat/zlib/contrib/masm686/match.asm deleted file mode 100644 index 4b03a71..0000000 --- a/compat/zlib/contrib/masm686/match.asm +++ /dev/null @@ -1,413 +0,0 @@ -
-; 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
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