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