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Diffstat (limited to 'human68k/match.s')
| -rw-r--r-- | human68k/match.s | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/human68k/match.s b/human68k/match.s new file mode 100644 index 0000000..4e6bc1c --- /dev/null +++ b/human68k/match.s @@ -0,0 +1,163 @@ +*=========================================================================== +* 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.s -- optional optimized asm version of longest match in deflate.c +* Written by Jean-loup Gailly +* +* Adapted for X68000 by NIIMI Satoshi <a01309@cfi.waseda.ac.jp> +* 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 machines to crash. +* For maximum speed, UNALIGNED_OK can be defined. +* The program will then only run on 68020-based machines, though. + + +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 + + + .xdef _match_init + .xdef _longest_match + + .text + .even + + +_match_init: + rts + + +_longest_match: + move.l 4(sp),Cur_Match +.ifdef UNALIGNED_OK + movem.l d2-d6/a2-a4,-(sp) +.else + movem.l d2-d7/a2-a4,-(sp) +.endif + 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 + +.ifdef UNALIGNED_OK + move.w -MIN_MATCH(Scan_Ini),Scan_Start + move.w -MIN_MATCH-1(Scan_Ini,Best_Len.w),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.w),Scan_End + lsl.w #8,Scan_End + move.b -MIN_MATCH(Scan_Ini,Best_Len.w),Scan_End +.endif + + bra.b do_scan + +long_loop: + +.ifdef UNALIGNED_OK + move.w -MIN_MATCH-1(Scan_Ini,Best_Len.w),Scan_End +.else + move.b -MIN_MATCH-1(Scan_Ini,Best_Len.w),Scan_End + lsl.w #8,Scan_End + move.b -MIN_MATCH(Scan_Ini,Best_Len.w),Scan_End +.endif + +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 + +.ifdef UNALIGNED_OK + cmp.w -MIN_MATCH-1(Match,Best_Len.w),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.w),Scan_Test + lsl.w #8,Scan_Test + move.b -MIN_MATCH(Match,Best_Len.w),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 +.endif + + 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 +.ifdef UNALIGNED_OK + movem.l (sp)+,d2-d6/a2-a4 +.else + movem.l (sp)+,d2-d7/a2-a4 +.endif + rts + + end |