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authorMark Adler <madler@alumni.caltech.edu>2011-09-09 23:24:43 -0700
committerMark Adler <madler@alumni.caltech.edu>2011-09-09 23:24:43 -0700
commit6b8233bfe00e79134cb1b84fc49d4f750a797f79 (patch)
treeca2b03b0169568681dc3d9c823e9f0bc4417d6b5 /contrib/asm586
parent0484693e1723bbab791c56f95597bd7dbe867d03 (diff)
downloadzlib-1.2.2.3.tar.gz
zlib-1.2.2.3.tar.bz2
zlib-1.2.2.3.zip
zlib 1.2.2.3v1.2.2.3
Diffstat (limited to 'contrib/asm586')
-rw-r--r--contrib/asm586/match.S718
1 files changed, 364 insertions, 354 deletions
diff --git a/contrib/asm586/match.S b/contrib/asm586/match.S
index 8f16140..371c9a0 100644
--- a/contrib/asm586/match.S
+++ b/contrib/asm586/match.S
@@ -1,354 +1,364 @@
1/* match.s -- Pentium-optimized version of longest_match() 1/* match.s -- Pentium-optimized version of longest_match()
2 * Written for zlib 1.1.2 2 * Written for zlib 1.1.2
3 * Copyright (C) 1998 Brian Raiter <breadbox@muppetlabs.com> 3 * Copyright (C) 1998 Brian Raiter <breadbox@muppetlabs.com>
4 * 4 *
5 * This is free software; you can redistribute it and/or modify it 5 * This is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License. 6 * under the terms of the GNU General Public License.
7 */ 7 */
8 8
9#ifndef NO_UNDERLINE 9#ifndef NO_UNDERLINE
10#define match_init _match_init 10#define match_init _match_init
11#define longest_match _longest_match 11#define longest_match _longest_match
12#endif 12#endif
13 13
14#define MAX_MATCH (258) 14#define MAX_MATCH (258)
15#define MIN_MATCH (3) 15#define MIN_MATCH (3)
16#define MIN_LOOKAHEAD (MAX_MATCH + MIN_MATCH + 1) 16#define MIN_LOOKAHEAD (MAX_MATCH + MIN_MATCH + 1)
17#define MAX_MATCH_8 ((MAX_MATCH + 7) & ~7) 17#define MAX_MATCH_8 ((MAX_MATCH + 7) & ~7)
18 18
19/* stack frame offsets */ 19/* stack frame offsets */
20 20
21#define wmask 0 /* local copy of s->wmask */ 21#define wmask 0 /* local copy of s->wmask */
22#define window 4 /* local copy of s->window */ 22#define window 4 /* local copy of s->window */
23#define windowbestlen 8 /* s->window + bestlen */ 23#define windowbestlen 8 /* s->window + bestlen */
24#define chainlenscanend 12 /* high word: current chain len */ 24#define chainlenscanend 12 /* high word: current chain len */
25 /* low word: last bytes sought */ 25 /* low word: last bytes sought */
26#define scanstart 16 /* first two bytes of string */ 26#define scanstart 16 /* first two bytes of string */
27#define scanalign 20 /* dword-misalignment of string */ 27#define scanalign 20 /* dword-misalignment of string */
28#define nicematch 24 /* a good enough match size */ 28#define nicematch 24 /* a good enough match size */
29#define bestlen 28 /* size of best match so far */ 29#define bestlen 28 /* size of best match so far */
30#define scan 32 /* ptr to string wanting match */ 30#define scan 32 /* ptr to string wanting match */
31 31
32#define LocalVarsSize (36) 32#define LocalVarsSize (36)
33/* saved ebx 36 */ 33/* saved ebx 36 */
34/* saved edi 40 */ 34/* saved edi 40 */
35/* saved esi 44 */ 35/* saved esi 44 */
36/* saved ebp 48 */ 36/* saved ebp 48 */
37/* return address 52 */ 37/* return address 52 */
38#define deflatestate 56 /* the function arguments */ 38#define deflatestate 56 /* the function arguments */
39#define curmatch 60 39#define curmatch 60
40 40
41/* Offsets for fields in the deflate_state structure. These numbers 41/* Offsets for fields in the deflate_state structure. These numbers
42 * are calculated from the definition of deflate_state, with the 42 * are calculated from the definition of deflate_state, with the
43 * assumption that the compiler will dword-align the fields. (Thus, 43 * assumption that the compiler will dword-align the fields. (Thus,
44 * changing the definition of deflate_state could easily cause this 44 * changing the definition of deflate_state could easily cause this
45 * program to crash horribly, without so much as a warning at 45 * program to crash horribly, without so much as a warning at
46 * compile time. Sigh.) 46 * compile time. Sigh.)
47 */ 47 */
48#define dsWSize 36 48
49#define dsWMask 44 49/* All the +zlib1222add offsets are due to the addition of fields
50#define dsWindow 48 50 * in zlib in the deflate_state structure since the asm code was first written
51#define dsPrev 56 51 * (if you compile with zlib 1.0.4 or older, use "zlib1222add equ (-4)").
52#define dsMatchLen 88 52 * (if you compile with zlib between 1.0.5 and 1.2.2.1, use "zlib1222add equ 0").
53#define dsPrevMatch 92 53 * if you compile with zlib 1.2.2.2 or later , use "zlib1222add equ 8").
54#define dsStrStart 100 54 */
55#define dsMatchStart 104 55
56#define dsLookahead 108 56#define zlib1222add (8)
57#define dsPrevLen 112 57
58#define dsMaxChainLen 116 58#define dsWSize (36+zlib1222add)
59#define dsGoodMatch 132 59#define dsWMask (44+zlib1222add)
60#define dsNiceMatch 136 60#define dsWindow (48+zlib1222add)
61 61#define dsPrev (56+zlib1222add)
62 62#define dsMatchLen (88+zlib1222add)
63.file "match.S" 63#define dsPrevMatch (92+zlib1222add)
64 64#define dsStrStart (100+zlib1222add)
65.globl match_init, longest_match 65#define dsMatchStart (104+zlib1222add)
66 66#define dsLookahead (108+zlib1222add)
67.text 67#define dsPrevLen (112+zlib1222add)
68 68#define dsMaxChainLen (116+zlib1222add)
69/* uInt longest_match(deflate_state *deflatestate, IPos curmatch) */ 69#define dsGoodMatch (132+zlib1222add)
70 70#define dsNiceMatch (136+zlib1222add)
71longest_match: 71
72 72
73/* Save registers that the compiler may be using, and adjust %esp to */ 73.file "match.S"
74/* make room for our stack frame. */ 74
75 75.globl match_init, longest_match
76 pushl %ebp 76
77 pushl %edi 77.text
78 pushl %esi 78
79 pushl %ebx 79/* uInt longest_match(deflate_state *deflatestate, IPos curmatch) */
80 subl $LocalVarsSize, %esp 80
81 81longest_match:
82/* Retrieve the function arguments. %ecx will hold cur_match */ 82
83/* throughout the entire function. %edx will hold the pointer to the */ 83/* Save registers that the compiler may be using, and adjust %esp to */
84/* deflate_state structure during the function's setup (before */ 84/* make room for our stack frame. */
85/* entering the main loop). */ 85
86 86 pushl %ebp
87 movl deflatestate(%esp), %edx 87 pushl %edi
88 movl curmatch(%esp), %ecx 88 pushl %esi
89 89 pushl %ebx
90/* if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead; */ 90 subl $LocalVarsSize, %esp
91 91
92 movl dsNiceMatch(%edx), %eax 92/* Retrieve the function arguments. %ecx will hold cur_match */
93 movl dsLookahead(%edx), %ebx 93/* throughout the entire function. %edx will hold the pointer to the */
94 cmpl %eax, %ebx 94/* deflate_state structure during the function's setup (before */
95 jl LookaheadLess 95/* entering the main loop). */
96 movl %eax, %ebx 96
97LookaheadLess: movl %ebx, nicematch(%esp) 97 movl deflatestate(%esp), %edx
98 98 movl curmatch(%esp), %ecx
99/* register Bytef *scan = s->window + s->strstart; */ 99
100 100/* if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead; */
101 movl dsWindow(%edx), %esi 101
102 movl %esi, window(%esp) 102 movl dsNiceMatch(%edx), %eax
103 movl dsStrStart(%edx), %ebp 103 movl dsLookahead(%edx), %ebx
104 lea (%esi,%ebp), %edi 104 cmpl %eax, %ebx
105 movl %edi, scan(%esp) 105 jl LookaheadLess
106 106 movl %eax, %ebx
107/* Determine how many bytes the scan ptr is off from being */ 107LookaheadLess: movl %ebx, nicematch(%esp)
108/* dword-aligned. */ 108
109 109/* register Bytef *scan = s->window + s->strstart; */
110 movl %edi, %eax 110
111 negl %eax 111 movl dsWindow(%edx), %esi
112 andl $3, %eax 112 movl %esi, window(%esp)
113 movl %eax, scanalign(%esp) 113 movl dsStrStart(%edx), %ebp
114 114 lea (%esi,%ebp), %edi
115/* IPos limit = s->strstart > (IPos)MAX_DIST(s) ? */ 115 movl %edi, scan(%esp)
116/* s->strstart - (IPos)MAX_DIST(s) : NIL; */ 116
117 117/* Determine how many bytes the scan ptr is off from being */
118 movl dsWSize(%edx), %eax 118/* dword-aligned. */
119 subl $MIN_LOOKAHEAD, %eax 119
120 subl %eax, %ebp 120 movl %edi, %eax
121 jg LimitPositive 121 negl %eax
122 xorl %ebp, %ebp 122 andl $3, %eax
123LimitPositive: 123 movl %eax, scanalign(%esp)
124 124
125/* unsigned chain_length = s->max_chain_length; */ 125/* IPos limit = s->strstart > (IPos)MAX_DIST(s) ? */
126/* if (s->prev_length >= s->good_match) { */ 126/* s->strstart - (IPos)MAX_DIST(s) : NIL; */
127/* chain_length >>= 2; */ 127
128/* } */ 128 movl dsWSize(%edx), %eax
129 129 subl $MIN_LOOKAHEAD, %eax
130 movl dsPrevLen(%edx), %eax 130 subl %eax, %ebp
131 movl dsGoodMatch(%edx), %ebx 131 jg LimitPositive
132 cmpl %ebx, %eax 132 xorl %ebp, %ebp
133 movl dsMaxChainLen(%edx), %ebx 133LimitPositive:
134 jl LastMatchGood 134
135 shrl $2, %ebx 135/* unsigned chain_length = s->max_chain_length; */
136LastMatchGood: 136/* if (s->prev_length >= s->good_match) { */
137 137/* chain_length >>= 2; */
138/* chainlen is decremented once beforehand so that the function can */ 138/* } */
139/* use the sign flag instead of the zero flag for the exit test. */ 139
140/* It is then shifted into the high word, to make room for the scanend */ 140 movl dsPrevLen(%edx), %eax
141/* scanend value, which it will always accompany. */ 141 movl dsGoodMatch(%edx), %ebx
142 142 cmpl %ebx, %eax
143 decl %ebx 143 movl dsMaxChainLen(%edx), %ebx
144 shll $16, %ebx 144 jl LastMatchGood
145 145 shrl $2, %ebx
146/* int best_len = s->prev_length; */ 146LastMatchGood:
147 147
148 movl dsPrevLen(%edx), %eax 148/* chainlen is decremented once beforehand so that the function can */
149 movl %eax, bestlen(%esp) 149/* use the sign flag instead of the zero flag for the exit test. */
150 150/* It is then shifted into the high word, to make room for the scanend */
151/* Store the sum of s->window + best_len in %esi locally, and in %esi. */ 151/* scanend value, which it will always accompany. */
152 152
153 addl %eax, %esi 153 decl %ebx
154 movl %esi, windowbestlen(%esp) 154 shll $16, %ebx
155 155
156/* register ush scan_start = *(ushf*)scan; */ 156/* int best_len = s->prev_length; */
157/* register ush scan_end = *(ushf*)(scan+best_len-1); */ 157
158 158 movl dsPrevLen(%edx), %eax
159 movw (%edi), %bx 159 movl %eax, bestlen(%esp)
160 movw %bx, scanstart(%esp) 160
161 movw -1(%edi,%eax), %bx 161/* Store the sum of s->window + best_len in %esi locally, and in %esi. */
162 movl %ebx, chainlenscanend(%esp) 162
163 163 addl %eax, %esi
164/* Posf *prev = s->prev; */ 164 movl %esi, windowbestlen(%esp)
165/* uInt wmask = s->w_mask; */ 165
166 166/* register ush scan_start = *(ushf*)scan; */
167 movl dsPrev(%edx), %edi 167/* register ush scan_end = *(ushf*)(scan+best_len-1); */
168 movl dsWMask(%edx), %edx 168
169 mov %edx, wmask(%esp) 169 movw (%edi), %bx
170 170 movw %bx, scanstart(%esp)
171/* Jump into the main loop. */ 171 movw -1(%edi,%eax), %bx
172 172 movl %ebx, chainlenscanend(%esp)
173 jmp LoopEntry 173
174 174/* Posf *prev = s->prev; */
175.balign 16 175/* uInt wmask = s->w_mask; */
176 176
177/* do { 177 movl dsPrev(%edx), %edi
178 * match = s->window + cur_match; 178 movl dsWMask(%edx), %edx
179 * if (*(ushf*)(match+best_len-1) != scan_end || 179 mov %edx, wmask(%esp)
180 * *(ushf*)match != scan_start) continue; 180
181 * [...] 181/* Jump into the main loop. */
182 * } while ((cur_match = prev[cur_match & wmask]) > limit 182
183 * && --chain_length != 0); 183 jmp LoopEntry
184 * 184
185 * Here is the inner loop of the function. The function will spend the 185.balign 16
186 * majority of its time in this loop, and majority of that time will 186
187 * be spent in the first ten instructions. 187/* do {
188 * 188 * match = s->window + cur_match;
189 * Within this loop: 189 * if (*(ushf*)(match+best_len-1) != scan_end ||
190 * %ebx = chainlenscanend - i.e., ((chainlen << 16) | scanend) 190 * *(ushf*)match != scan_start) continue;
191 * %ecx = curmatch 191 * [...]
192 * %edx = curmatch & wmask 192 * } while ((cur_match = prev[cur_match & wmask]) > limit
193 * %esi = windowbestlen - i.e., (window + bestlen) 193 * && --chain_length != 0);
194 * %edi = prev 194 *
195 * %ebp = limit 195 * Here is the inner loop of the function. The function will spend the
196 * 196 * majority of its time in this loop, and majority of that time will
197 * Two optimization notes on the choice of instructions: 197 * be spent in the first ten instructions.
198 * 198 *
199 * The first instruction uses a 16-bit address, which costs an extra, 199 * Within this loop:
200 * unpairable cycle. This is cheaper than doing a 32-bit access and 200 * %ebx = chainlenscanend - i.e., ((chainlen << 16) | scanend)
201 * zeroing the high word, due to the 3-cycle misalignment penalty which 201 * %ecx = curmatch
202 * would occur half the time. This also turns out to be cheaper than 202 * %edx = curmatch & wmask
203 * doing two separate 8-bit accesses, as the memory is so rarely in the 203 * %esi = windowbestlen - i.e., (window + bestlen)
204 * L1 cache. 204 * %edi = prev
205 * 205 * %ebp = limit
206 * The window buffer, however, apparently spends a lot of time in the 206 *
207 * cache, and so it is faster to retrieve the word at the end of the 207 * Two optimization notes on the choice of instructions:
208 * match string with two 8-bit loads. The instructions that test the 208 *
209 * word at the beginning of the match string, however, are executed 209 * The first instruction uses a 16-bit address, which costs an extra,
210 * much less frequently, and there it was cheaper to use 16-bit 210 * unpairable cycle. This is cheaper than doing a 32-bit access and
211 * instructions, which avoided the necessity of saving off and 211 * zeroing the high word, due to the 3-cycle misalignment penalty which
212 * subsequently reloading one of the other registers. 212 * would occur half the time. This also turns out to be cheaper than
213 */ 213 * doing two separate 8-bit accesses, as the memory is so rarely in the
214LookupLoop: 214 * L1 cache.
215 /* 1 U & V */ 215 *
216 movw (%edi,%edx,2), %cx /* 2 U pipe */ 216 * The window buffer, however, apparently spends a lot of time in the
217 movl wmask(%esp), %edx /* 2 V pipe */ 217 * cache, and so it is faster to retrieve the word at the end of the
218 cmpl %ebp, %ecx /* 3 U pipe */ 218 * match string with two 8-bit loads. The instructions that test the
219 jbe LeaveNow /* 3 V pipe */ 219 * word at the beginning of the match string, however, are executed
220 subl $0x00010000, %ebx /* 4 U pipe */ 220 * much less frequently, and there it was cheaper to use 16-bit
221 js LeaveNow /* 4 V pipe */ 221 * instructions, which avoided the necessity of saving off and
222LoopEntry: movb -1(%esi,%ecx), %al /* 5 U pipe */ 222 * subsequently reloading one of the other registers.
223 andl %ecx, %edx /* 5 V pipe */ 223 */
224 cmpb %bl, %al /* 6 U pipe */ 224LookupLoop:
225 jnz LookupLoop /* 6 V pipe */ 225 /* 1 U & V */
226 movb (%esi,%ecx), %ah 226 movw (%edi,%edx,2), %cx /* 2 U pipe */
227 cmpb %bh, %ah 227 movl wmask(%esp), %edx /* 2 V pipe */
228 jnz LookupLoop 228 cmpl %ebp, %ecx /* 3 U pipe */
229 movl window(%esp), %eax 229 jbe LeaveNow /* 3 V pipe */
230 movw (%eax,%ecx), %ax 230 subl $0x00010000, %ebx /* 4 U pipe */
231 cmpw scanstart(%esp), %ax 231 js LeaveNow /* 4 V pipe */
232 jnz LookupLoop 232LoopEntry: movb -1(%esi,%ecx), %al /* 5 U pipe */
233 233 andl %ecx, %edx /* 5 V pipe */
234/* Store the current value of chainlen. */ 234 cmpb %bl, %al /* 6 U pipe */
235 235 jnz LookupLoop /* 6 V pipe */
236 movl %ebx, chainlenscanend(%esp) 236 movb (%esi,%ecx), %ah
237 237 cmpb %bh, %ah
238/* Point %edi to the string under scrutiny, and %esi to the string we */ 238 jnz LookupLoop
239/* are hoping to match it up with. In actuality, %esi and %edi are */ 239 movl window(%esp), %eax
240/* both pointed (MAX_MATCH_8 - scanalign) bytes ahead, and %edx is */ 240 movw (%eax,%ecx), %ax
241/* initialized to -(MAX_MATCH_8 - scanalign). */ 241 cmpw scanstart(%esp), %ax
242 242 jnz LookupLoop
243 movl window(%esp), %esi 243
244 movl scan(%esp), %edi 244/* Store the current value of chainlen. */
245 addl %ecx, %esi 245
246 movl scanalign(%esp), %eax 246 movl %ebx, chainlenscanend(%esp)
247 movl $(-MAX_MATCH_8), %edx 247
248 lea MAX_MATCH_8(%edi,%eax), %edi 248/* Point %edi to the string under scrutiny, and %esi to the string we */
249 lea MAX_MATCH_8(%esi,%eax), %esi 249/* are hoping to match it up with. In actuality, %esi and %edi are */
250 250/* both pointed (MAX_MATCH_8 - scanalign) bytes ahead, and %edx is */
251/* Test the strings for equality, 8 bytes at a time. At the end, 251/* initialized to -(MAX_MATCH_8 - scanalign). */
252 * adjust %edx so that it is offset to the exact byte that mismatched. 252
253 * 253 movl window(%esp), %esi
254 * We already know at this point that the first three bytes of the 254 movl scan(%esp), %edi
255 * strings match each other, and they can be safely passed over before 255 addl %ecx, %esi
256 * starting the compare loop. So what this code does is skip over 0-3 256 movl scanalign(%esp), %eax
257 * bytes, as much as necessary in order to dword-align the %edi 257 movl $(-MAX_MATCH_8), %edx
258 * pointer. (%esi will still be misaligned three times out of four.) 258 lea MAX_MATCH_8(%edi,%eax), %edi
259 * 259 lea MAX_MATCH_8(%esi,%eax), %esi
260 * It should be confessed that this loop usually does not represent 260
261 * much of the total running time. Replacing it with a more 261/* Test the strings for equality, 8 bytes at a time. At the end,
262 * straightforward "rep cmpsb" would not drastically degrade 262 * adjust %edx so that it is offset to the exact byte that mismatched.
263 * performance. 263 *
264 */ 264 * We already know at this point that the first three bytes of the
265LoopCmps: 265 * strings match each other, and they can be safely passed over before
266 movl (%esi,%edx), %eax 266 * starting the compare loop. So what this code does is skip over 0-3
267 movl (%edi,%edx), %ebx 267 * bytes, as much as necessary in order to dword-align the %edi
268 xorl %ebx, %eax 268 * pointer. (%esi will still be misaligned three times out of four.)
269 jnz LeaveLoopCmps 269 *
270 movl 4(%esi,%edx), %eax 270 * It should be confessed that this loop usually does not represent
271 movl 4(%edi,%edx), %ebx 271 * much of the total running time. Replacing it with a more
272 xorl %ebx, %eax 272 * straightforward "rep cmpsb" would not drastically degrade
273 jnz LeaveLoopCmps4 273 * performance.
274 addl $8, %edx 274 */
275 jnz LoopCmps 275LoopCmps:
276 jmp LenMaximum 276 movl (%esi,%edx), %eax
277LeaveLoopCmps4: addl $4, %edx 277 movl (%edi,%edx), %ebx
278LeaveLoopCmps: testl $0x0000FFFF, %eax 278 xorl %ebx, %eax
279 jnz LenLower 279 jnz LeaveLoopCmps
280 addl $2, %edx 280 movl 4(%esi,%edx), %eax
281 shrl $16, %eax 281 movl 4(%edi,%edx), %ebx
282LenLower: subb $1, %al 282 xorl %ebx, %eax
283 adcl $0, %edx 283 jnz LeaveLoopCmps4
284 284 addl $8, %edx
285/* Calculate the length of the match. If it is longer than MAX_MATCH, */ 285 jnz LoopCmps
286/* then automatically accept it as the best possible match and leave. */ 286 jmp LenMaximum
287 287LeaveLoopCmps4: addl $4, %edx
288 lea (%edi,%edx), %eax 288LeaveLoopCmps: testl $0x0000FFFF, %eax
289 movl scan(%esp), %edi 289 jnz LenLower
290 subl %edi, %eax 290 addl $2, %edx
291 cmpl $MAX_MATCH, %eax 291 shrl $16, %eax
292 jge LenMaximum 292LenLower: subb $1, %al
293 293 adcl $0, %edx
294/* If the length of the match is not longer than the best match we */ 294
295/* have so far, then forget it and return to the lookup loop. */ 295/* Calculate the length of the match. If it is longer than MAX_MATCH, */
296 296/* then automatically accept it as the best possible match and leave. */
297 movl deflatestate(%esp), %edx 297
298 movl bestlen(%esp), %ebx 298 lea (%edi,%edx), %eax
299 cmpl %ebx, %eax 299 movl scan(%esp), %edi
300 jg LongerMatch 300 subl %edi, %eax
301 movl chainlenscanend(%esp), %ebx 301 cmpl $MAX_MATCH, %eax
302 movl windowbestlen(%esp), %esi 302 jge LenMaximum
303 movl dsPrev(%edx), %edi 303
304 movl wmask(%esp), %edx 304/* If the length of the match is not longer than the best match we */
305 andl %ecx, %edx 305/* have so far, then forget it and return to the lookup loop. */
306 jmp LookupLoop 306
307 307 movl deflatestate(%esp), %edx
308/* s->match_start = cur_match; */ 308 movl bestlen(%esp), %ebx
309/* best_len = len; */ 309 cmpl %ebx, %eax
310/* if (len >= nice_match) break; */ 310 jg LongerMatch
311/* scan_end = *(ushf*)(scan+best_len-1); */ 311 movl chainlenscanend(%esp), %ebx
312 312 movl windowbestlen(%esp), %esi
313LongerMatch: movl nicematch(%esp), %ebx 313 movl dsPrev(%edx), %edi
314 movl %eax, bestlen(%esp) 314 movl wmask(%esp), %edx
315 movl %ecx, dsMatchStart(%edx) 315 andl %ecx, %edx
316 cmpl %ebx, %eax 316 jmp LookupLoop
317 jge LeaveNow 317
318 movl window(%esp), %esi 318/* s->match_start = cur_match; */
319 addl %eax, %esi 319/* best_len = len; */
320 movl %esi, windowbestlen(%esp) 320/* if (len >= nice_match) break; */
321 movl chainlenscanend(%esp), %ebx 321/* scan_end = *(ushf*)(scan+best_len-1); */
322 movw -1(%edi,%eax), %bx 322
323 movl dsPrev(%edx), %edi 323LongerMatch: movl nicematch(%esp), %ebx
324 movl %ebx, chainlenscanend(%esp) 324 movl %eax, bestlen(%esp)
325 movl wmask(%esp), %edx 325 movl %ecx, dsMatchStart(%edx)
326 andl %ecx, %edx 326 cmpl %ebx, %eax
327 jmp LookupLoop 327 jge LeaveNow
328 328 movl window(%esp), %esi
329/* Accept the current string, with the maximum possible length. */ 329 addl %eax, %esi
330 330 movl %esi, windowbestlen(%esp)
331LenMaximum: movl deflatestate(%esp), %edx 331 movl chainlenscanend(%esp), %ebx
332 movl $MAX_MATCH, bestlen(%esp) 332 movw -1(%edi,%eax), %bx
333 movl %ecx, dsMatchStart(%edx) 333 movl dsPrev(%edx), %edi
334 334 movl %ebx, chainlenscanend(%esp)
335/* if ((uInt)best_len <= s->lookahead) return (uInt)best_len; */ 335 movl wmask(%esp), %edx
336/* return s->lookahead; */ 336 andl %ecx, %edx
337 337 jmp LookupLoop
338LeaveNow: 338
339 movl deflatestate(%esp), %edx 339/* Accept the current string, with the maximum possible length. */
340 movl bestlen(%esp), %ebx 340
341 movl dsLookahead(%edx), %eax 341LenMaximum: movl deflatestate(%esp), %edx
342 cmpl %eax, %ebx 342 movl $MAX_MATCH, bestlen(%esp)
343 jg LookaheadRet 343 movl %ecx, dsMatchStart(%edx)
344 movl %ebx, %eax 344
345LookaheadRet: 345/* if ((uInt)best_len <= s->lookahead) return (uInt)best_len; */
346 346/* return s->lookahead; */
347/* Restore the stack and return from whence we came. */ 347
348 348LeaveNow:
349 addl $LocalVarsSize, %esp 349 movl deflatestate(%esp), %edx
350 popl %ebx 350 movl bestlen(%esp), %ebx
351 popl %esi 351 movl dsLookahead(%edx), %eax
352 popl %edi 352 cmpl %eax, %ebx
353 popl %ebp 353 jg LookaheadRet
354match_init: ret 354 movl %ebx, %eax
355LookaheadRet:
356
357/* Restore the stack and return from whence we came. */
358
359 addl $LocalVarsSize, %esp
360 popl %ebx
361 popl %esi
362 popl %edi
363 popl %ebp
364match_init: ret
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