+++ /dev/null
-; match.a -- 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.
-
-; 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.
-;
-; 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
-WSIZE equ 32768
-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),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),Scan_End
- lsl.w #8,Scan_End
- move.b -MIN_MATCH(Scan_Ini,Best_Len),Scan_End
-
- endc
-
- bra.b do_scan
-
-long_loop:
-
- ifd UNALIGNED_OK
-
- move.w -MIN_MATCH-1(Scan_Ini,Best_Len),Scan_End
-
- else
-
- move.b -MIN_MATCH-1(Scan_Ini,Best_Len),Scan_End
- lsl.w #8,Scan_End
- move.b -MIN_MATCH(Scan_Ini,Best_Len),Scan_End
-
- endc
-
-short_loop:
- lsl.w #1,Cur_Match
- move.w 0(Prev_Address,Cur_Match),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),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),Scan_Test
- lsl.w #8,Scan_Test
- move.b -MIN_MATCH(Match,Best_Len),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
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