380 lines
12 KiB
ArmAsm
380 lines
12 KiB
ArmAsm
/* match.s -- optional optimized asm version of longest match in deflate.c
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* Copyright (C) 1992-1993 Jean-loup Gailly
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* This is free software; you can redistribute it and/or modify it under the
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* terms of the GNU General Public License, see the file COPYING.
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*
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* The 68020 version has been written by Francesco Potorti` <pot@cnuce.cnr.it>
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* with adaptations by Carsten Steger <stegerc@informatik.tu-muenchen.de>,
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* Andreas Schwab <schwab@lamothe.informatik.uni-dortmund.de> and
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* Kristoffer Eriksson <ske@pkmab.se>
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*/
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/* $Id: match.S,v 1.5 1997/02/22 15:45:59 peter Exp $ */
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/* Preprocess with -DNO_UNDERLINE if your C compiler does not prefix
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* external symbols with an underline character '_'.
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*/
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#ifdef __ELF__ /* NO_UNDERLINE */
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# define _prev prev
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# define _window window
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# define _match_start match_start
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# define _prev_length prev_length
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# define _good_match good_match
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# define _nice_match nice_match
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# define _strstart strstart
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# define _max_chain_length max_chain_length
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# define _match_init match_init
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# define _longest_match longest_match
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#endif
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#ifdef DYN_ALLOC
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error: DYN_ALLOC not yet supported in match.s
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#endif
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#if defined(i386) || defined(_I386)
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/* This version is for 386 Unix or OS/2 in 32 bit mode.
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* Warning: it uses the AT&T syntax: mov source,dest
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* This file is only optional. If you want to force the C version,
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* add -DNO_ASM to CFLAGS in Makefile and set OBJA to an empty string.
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* If you have reduced WSIZE in gzip.h, then change its value below.
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* This version assumes static allocation of the arrays (-DDYN_ALLOC not used).
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*/
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.file "match.S"
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#define MAX_MATCH 258
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#define MAX_MATCH2 $128 /* MAX_MATCH/2-1 */
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#define MIN_MATCH 3
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#define WSIZE $32768
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#define MAX_DIST WSIZE - MAX_MATCH - MIN_MATCH - 1
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.globl _match_init
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.globl _longest_match
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.text
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_match_init:
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ret
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/*-----------------------------------------------------------------------
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* Set match_start to the longest match starting at the given string and
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* return its length. Matches shorter or equal to prev_length are discarded,
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* in which case the result is equal to prev_length and match_start is
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* garbage.
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* IN assertions: cur_match is the head of the hash chain for the current
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* string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
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*/
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_longest_match: /* int longest_match(cur_match) */
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#define cur_match 20(%esp)
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/* return address */ /* esp+16 */
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push %ebp /* esp+12 */
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push %edi /* esp+8 */
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push %esi /* esp+4 */
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push %ebx /* esp */
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/*
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* match equ esi
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* scan equ edi
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* chain_length equ ebp
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* best_len equ ebx
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* limit equ edx
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*/
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mov cur_match,%esi
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mov _max_chain_length,%ebp /* chain_length = max_chain_length */
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mov _strstart,%edi
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mov %edi,%edx
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sub MAX_DIST,%edx /* limit = strstart-MAX_DIST */
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jae limit_ok
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sub %edx,%edx /* limit = NIL */
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limit_ok:
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add $2+_window,%edi /* edi = offset(window+strstart+2) */
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mov _prev_length,%ebx /* best_len = prev_length */
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movw -3(%ebx,%edi),%ax /* ax = scan[best_len-1..best_len] */
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movw -2(%edi),%cx /* cx = scan[0..1] */
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cmp _good_match,%ebx /* do we have a good match already? */
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jb do_scan
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shr $2,%ebp /* chain_length >>= 2 */
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jmp do_scan
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.align 4
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long_loop:
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/* at this point, edi == scan+2, esi == cur_match */
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movw -3(%ebx,%edi),%ax /* ax = scan[best_len-1..best_len] */
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movw -2(%edi),%cx /* cx = scan[0..1] */
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short_loop:
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/*
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* at this point, di == scan+2, si == cur_match,
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* ax = scan[best_len-1..best_len] and cx = scan[0..1]
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*/
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and WSIZE-1, %esi
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movw _prev(%esi,%esi),%si /* cur_match = prev[cur_match] */
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/* top word of esi is still 0 */
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cmp %edx,%esi /* cur_match <= limit ? */
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jbe the_end
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dec %ebp /* --chain_length */
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jz the_end
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do_scan:
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cmpw _window-1(%ebx,%esi),%ax/* check match at best_len-1 */
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jne short_loop
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cmpw _window(%esi),%cx /* check min_match_length match */
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jne short_loop
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lea _window+2(%esi),%esi /* si = match */
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mov %edi,%eax /* ax = scan+2 */
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mov MAX_MATCH2,%ecx /* scan for at most MAX_MATCH bytes */
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rep; cmpsw /* loop until mismatch */
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je maxmatch /* match of length MAX_MATCH? */
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mismatch:
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movb -2(%edi),%cl /* mismatch on first or second byte? */
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subb -2(%esi),%cl /* cl = 0 if first bytes equal */
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xchg %edi,%eax /* edi = scan+2, eax = end of scan */
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sub %edi,%eax /* eax = len */
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sub %eax,%esi /* esi = cur_match + 2 + offset(window) */
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sub $2+_window,%esi /* esi = cur_match */
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subb $1,%cl /* set carry if cl == 0 (cannot use DEC) */
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adc $0,%eax /* eax = carry ? len+1 : len */
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cmp %ebx,%eax /* len > best_len ? */
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jle long_loop
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mov %esi,_match_start /* match_start = cur_match */
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mov %eax,%ebx /* ebx = best_len = len */
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cmp _nice_match,%eax /* len >= nice_match ? */
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jl long_loop
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the_end:
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mov %ebx,%eax /* result = eax = best_len */
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pop %ebx
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pop %esi
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pop %edi
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pop %ebp
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ret
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maxmatch:
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cmpsb
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jmp mismatch
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#else
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/* ======================== 680x0 version ================================= */
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#if defined(m68k)||defined(mc68k)||defined(__mc68000__)||defined(__MC68000__)
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# ifndef mc68000
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# define mc68000
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# endif
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#endif
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#if defined(__mc68020__) || defined(__MC68020__) || defined(sysV68)
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# ifndef mc68020
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# define mc68020
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# endif
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#endif
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#if defined(mc68020) || defined(mc68000)
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#if (defined(mc68020) || defined(NeXT)) && !defined(UNALIGNED_OK)
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# define UNALIGNED_OK
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#endif
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#ifdef sysV68 /* Try Motorola Delta style */
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# define GLOBAL(symbol) global symbol
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# define TEXT text
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# define FILE(filename) file filename
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# define invert_maybe(src,dst) dst,src
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# define imm(data) &data
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# define reg(register) %register
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# define addl add.l
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# define addql addq.l
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# define blos blo.b
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# define bhis bhi.b
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# define bras bra.b
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# define clrl clr.l
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# define cmpmb cmpm.b
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# define cmpw cmp.w
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# define cmpl cmp.l
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# define lslw lsl.w
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# define lsrl lsr.l
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# define movel move.l
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# define movew move.w
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# define moveb move.b
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# define moveml movem.l
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# define subl sub.l
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# define subw sub.w
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# define subql subq.l
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# define IndBase(bd,An) (bd,An)
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# define IndBaseNdxl(bd,An,Xn) (bd,An,Xn.l)
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# define IndBaseNdxw(bd,An,Xn) (bd,An,Xn.w)
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# define predec(An) -(An)
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# define postinc(An) (An)+
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#else /* default style (Sun 3, NeXT, Amiga, Atari) */
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# define GLOBAL(symbol) .globl symbol
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# define TEXT .text
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# define FILE(filename) .even
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# define invert_maybe(src,dst) src,dst
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# if defined(sun) || defined(mc68k)
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# define imm(data) #data
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# else
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# define imm(data) \#data
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# endif
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# define reg(register) register
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# define blos bcss
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# if defined(sun) || defined(mc68k)
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# define movel movl
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# define movew movw
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# define moveb movb
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# endif
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# define IndBase(bd,An) An@(bd)
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# define IndBaseNdxl(bd,An,Xn) An@(bd,Xn:l)
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# define IndBaseNdxw(bd,An,Xn) An@(bd,Xn:w)
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# define predec(An) An@-
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# define postinc(An) An@+
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#endif /* styles */
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#define Best_Len reg(d0) /* unsigned */
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#define Cur_Match reg(d1) /* Ipos */
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#define Loop_Counter reg(d2) /* int */
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#define Scan_Start reg(d3) /* unsigned short */
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#define Scan_End reg(d4) /* unsigned short */
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#define Limit reg(d5) /* IPos */
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#define Chain_Length reg(d6) /* unsigned */
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#define Scan_Test reg(d7)
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#define Scan reg(a0) /* *uch */
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#define Match reg(a1) /* *uch */
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#define Prev_Address reg(a2) /* *Pos */
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#define Scan_Ini reg(a3) /* *uch */
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#define Match_Ini reg(a4) /* *uch */
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#define Stack_Pointer reg(sp)
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#define MAX_MATCH 258
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#define MIN_MATCH 3
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#define WSIZE 32768
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#define MAX_DIST (WSIZE - MAX_MATCH - MIN_MATCH - 1)
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GLOBAL (_match_init)
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GLOBAL (_longest_match)
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TEXT
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FILE ("match.S")
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_match_init:
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rts
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/*-----------------------------------------------------------------------
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* Set match_start to the longest match starting at the given string and
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* return its length. Matches shorter or equal to prev_length are discarded,
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* in which case the result is equal to prev_length and match_start is
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* garbage.
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* IN assertions: cur_match is the head of the hash chain for the current
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* string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
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*/
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/* int longest_match (cur_match) */
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#ifdef UNALIGNED_OK
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# define pushreg 15928 /* d2-d6/a2-a4 */
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# define popreg 7292
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#else
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# define pushreg 16184 /* d2-d7/a2-a4 */
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# define popreg 7420
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#endif
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_longest_match:
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movel IndBase(4,Stack_Pointer),Cur_Match
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moveml imm(pushreg),predec(Stack_Pointer)
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movel _max_chain_length,Chain_Length
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movel _prev_length,Best_Len
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movel imm(_prev),Prev_Address
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movel imm(_window+MIN_MATCH),Match_Ini
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movel _strstart,Limit
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movel Match_Ini,Scan_Ini
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addl Limit,Scan_Ini
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subw imm(MAX_DIST),Limit
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bhis L__limit_ok
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clrl Limit
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L__limit_ok:
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cmpl invert_maybe(_good_match,Best_Len)
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blos L__length_ok
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lsrl imm(2),Chain_Length
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L__length_ok:
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subql imm(1),Chain_Length
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#ifdef UNALIGNED_OK
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movew IndBase(-MIN_MATCH,Scan_Ini),Scan_Start
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movew IndBaseNdxw(-MIN_MATCH-1,Scan_Ini,Best_Len),Scan_End
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#else
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moveb IndBase(-MIN_MATCH,Scan_Ini),Scan_Start
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lslw imm(8),Scan_Start
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moveb IndBase(-MIN_MATCH+1,Scan_Ini),Scan_Start
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moveb IndBaseNdxw(-MIN_MATCH-1,Scan_Ini,Best_Len),Scan_End
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lslw imm(8),Scan_End
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moveb IndBaseNdxw(-MIN_MATCH,Scan_Ini,Best_Len),Scan_End
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#endif
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bras L__do_scan
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L__long_loop:
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#ifdef UNALIGNED_OK
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movew IndBaseNdxw(-MIN_MATCH-1,Scan_Ini,Best_Len),Scan_End
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#else
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moveb IndBaseNdxw(-MIN_MATCH-1,Scan_Ini,Best_Len),Scan_End
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lslw imm(8),Scan_End
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moveb IndBaseNdxw(-MIN_MATCH,Scan_Ini,Best_Len),Scan_End
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#endif
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L__short_loop:
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lslw imm(1),Cur_Match
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movew IndBaseNdxl(0,Prev_Address,Cur_Match),Cur_Match
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cmpw invert_maybe(Limit,Cur_Match)
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dbls Chain_Length,L__do_scan
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bras L__return
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L__do_scan:
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movel Match_Ini,Match
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addl Cur_Match,Match
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#ifdef UNALIGNED_OK
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cmpw invert_maybe(IndBaseNdxw(-MIN_MATCH-1,Match,Best_Len),Scan_End)
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bne L__short_loop
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cmpw invert_maybe(IndBase(-MIN_MATCH,Match),Scan_Start)
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bne L__short_loop
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#else
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moveb IndBaseNdxw(-MIN_MATCH-1,Match,Best_Len),Scan_Test
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lslw imm(8),Scan_Test
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moveb IndBaseNdxw(-MIN_MATCH,Match,Best_Len),Scan_Test
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cmpw invert_maybe(Scan_Test,Scan_End)
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bne L__short_loop
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moveb IndBase(-MIN_MATCH,Match),Scan_Test
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lslw imm(8),Scan_Test
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moveb IndBase(-MIN_MATCH+1,Match),Scan_Test
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cmpw invert_maybe(Scan_Test,Scan_Start)
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bne L__short_loop
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#endif
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movew imm((MAX_MATCH-MIN_MATCH+1)-1),Loop_Counter
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movel Scan_Ini,Scan
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L__scan_loop:
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cmpmb postinc(Match),postinc(Scan)
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dbne Loop_Counter,L__scan_loop
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subl Scan_Ini,Scan
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addql imm(MIN_MATCH-1),Scan
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cmpl invert_maybe(Best_Len,Scan)
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bls L__short_loop
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movel Scan,Best_Len
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movel Cur_Match,_match_start
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cmpl invert_maybe(_nice_match,Best_Len)
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blos L__long_loop
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L__return:
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moveml postinc(Stack_Pointer),imm(popreg)
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rts
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#else
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error: this asm version is for 386 or 680x0 only
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#endif /* mc68000 || mc68020 */
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#endif /* i386 || _I386 */
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