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Diffstat (limited to 'amiga/match.a')
| -rw-r--r-- | amiga/match.a | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/amiga/match.a b/amiga/match.a new file mode 100644 index 0000000..ec5bcf0 --- /dev/null +++ b/amiga/match.a @@ -0,0 +1,182 @@ +;=========================================================================== +; Copyright (c) 1990-1999 Info-ZIP. All rights reserved. +; +; See the accompanying file LICENSE, version 1999-Oct-05 or later +; (the contents of which are also included in zip.h) for terms of use. +; If, for some reason, both of these files are missing, the Info-ZIP license +; also may be found at: ftp://ftp.cdrom.com/pub/infozip/license.html +;=========================================================================== +; match.a -- optional optimized asm version of longest match in deflate.c +; Written by Jean-loup Gailly +; Adapted for the Amiga by Carsten Steger <stegerc@informatik.tu-muenchen.de> +; using the code in match.S. +; The major change in this code consists of removing all unaligned +; word accesses, because they cause 68000-based Amigas to crash. +; For maximum speed, UNALIGNED_OK can be defined in Makefile.sasc. +; The program will then only run on 68020-based Amigas, though. +; If you have reduced WSIZE in zip.h, then make sure this is +; assembled with an equivalent -dWSIZE=<whatever>. +; +; This code will run with registerized parameters too, unless SAS +; changes parameter passing conventions between new releases of SAS/C. + + +Cur_Match reg d0 ; Must be in d0! +Best_Len reg d1 +Loop_Counter reg d2 +Scan_Start reg d3 +Scan_End reg d4 +Limit reg d5 +Chain_Length reg d6 +Scan_Test reg d7 +Scan reg a0 +Match reg a1 +Prev_Address reg a2 +Scan_Ini reg a3 +Match_Ini reg a4 + +MAX_MATCH equ 258 +MIN_MATCH equ 3 + ifnd WSIZE +WSIZE equ 32768 + endc +MAX_DIST equ WSIZE-MAX_MATCH-MIN_MATCH-1 + + + xref _max_chain_length + xref _prev_length + xref _prev + xref _window + xref _strstart + xref _good_match + xref _match_start + xref _nice_match + + + section match,code + + xdef _match_init + xdef @match_init + xdef _longest_match + xdef @longest_match + + +_match_init: +@match_init: + rts + + +_longest_match: + move.l 4(sp),Cur_Match +@longest_match: + ifd UNALIGNED_OK + movem.l d2-d6/a2-a4,-(sp) + else + movem.l d2-d7/a2-a4,-(sp) + endc + move.l _max_chain_length,Chain_Length + move.l _prev_length,Best_Len + lea _prev,Prev_Address + lea _window+MIN_MATCH,Match_Ini + move.l _strstart,Limit + move.l Match_Ini,Scan_Ini + add.l Limit,Scan_Ini + subi.w #MAX_DIST,Limit + bhi.b limit_ok + moveq #0,Limit +limit_ok: + cmp.l _good_match,Best_Len + bcs.b length_ok + lsr.l #2,Chain_Length +length_ok: + subq.l #1,Chain_Length + + ifd UNALIGNED_OK + + move.w -MIN_MATCH(Scan_Ini),Scan_Start + move.w -MIN_MATCH-1(Scan_Ini,Best_Len.L),Scan_End + + else + + move.b -MIN_MATCH(Scan_Ini),Scan_Start + lsl.w #8,Scan_Start + move.b -MIN_MATCH+1(Scan_Ini),Scan_Start + move.b -MIN_MATCH-1(Scan_Ini,Best_Len.L),Scan_End + lsl.w #8,Scan_End + move.b -MIN_MATCH(Scan_Ini,Best_Len.L),Scan_End + + endc + + bra.b do_scan + +long_loop: + + ifd UNALIGNED_OK + + move.w -MIN_MATCH-1(Scan_Ini,Best_Len.L),Scan_End + + else + + move.b -MIN_MATCH-1(Scan_Ini,Best_Len.L),Scan_End + lsl.w #8,Scan_End + move.b -MIN_MATCH(Scan_Ini,Best_Len.L),Scan_End + + endc + +short_loop: + lsl.w #1,Cur_Match + move.w 0(Prev_Address,Cur_Match.L),Cur_Match + cmp.w Limit,Cur_Match + dbls Chain_Length,do_scan + bra.b return + +do_scan: + move.l Match_Ini,Match + add.l Cur_Match,Match + + ifd UNALIGNED_OK + + cmp.w -MIN_MATCH-1(Match,Best_Len.L),Scan_End + bne.b short_loop + cmp.w -MIN_MATCH(Match),Scan_Start + bne.b short_loop + + else + + move.b -MIN_MATCH-1(Match,Best_Len.L),Scan_Test + lsl.w #8,Scan_Test + move.b -MIN_MATCH(Match,Best_Len.L),Scan_Test + cmp.w Scan_Test,Scan_End + bne.b short_loop + move.b -MIN_MATCH(Match),Scan_Test + lsl.w #8,Scan_Test + move.b -MIN_MATCH+1(Match),Scan_Test + cmp.w Scan_Test,Scan_Start + bne.b short_loop + + endc + + move.w #(MAX_MATCH-MIN_MATCH),Loop_Counter + move.l Scan_Ini,Scan +scan_loop: + cmpm.b (Match)+,(Scan)+ + dbne Loop_Counter,scan_loop + + sub.l Scan_Ini,Scan + addq.l #(MIN_MATCH-1),Scan + cmp.l Best_Len,Scan + bls.b short_loop + move.l Scan,Best_Len + move.l Cur_Match,_match_start + cmp.l _nice_match,Best_Len + bcs.b long_loop +return: + move.l Best_Len,d0 + ifd UNALIGNED_OK + movem.l (sp)+,d2-d6/a2-a4 + else + movem.l (sp)+,d2-d7/a2-a4 + endc + rts + + end |