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Diffstat (limited to 'acorn/match.s')
| -rw-r--r-- | acorn/match.s | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/acorn/match.s b/acorn/match.s new file mode 100644 index 0000000..ee68ce6 --- /dev/null +++ b/acorn/match.s @@ -0,0 +1,217 @@ +;=========================================================================== +; 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 for ARM by Sergio Monesi. + +r0 RN 0 +r1 RN 1 +r2 RN 2 +r3 RN 3 +r4 RN 4 +r5 RN 5 +r6 RN 6 +r7 RN 7 +r8 RN 8 +r9 RN 9 +sl RN 10 +fp RN 11 +ip RN 12 +sp RN 13 +lr RN 14 +pc RN 15 + +MAX_DIST EQU 32506 +WMASK EQU 32767 +MAX_MATCH EQU 258 + + AREA |C$$code|, CODE, READONLY + + +; r1 = chain_lenght +; r2 = scan +; r3 = match +; r4 = len (tmp) +; r5 = best_len +; r6 = limit +; r7 = strend +; r8 = scan_end1 +; r9 = scan_end +; lr = window +; fp = prev + +|__max_chain_length| + IMPORT max_chain_length + DCD max_chain_length +|__window| + IMPORT window + DCD window +|__prev| + IMPORT prev + DCD prev +|__prev_length| + IMPORT prev_length + DCD prev_length +|__strstart| + IMPORT strstart + DCD strstart +|__good_match| + IMPORT good_match + DCD good_match +|__nice_match| + IMPORT nice_match + DCD nice_match +|__match_start| + IMPORT match_start + DCD match_start + + DCB "longest_match" + DCB &00,&00,&00 + DCD &ff000010 + + EXPORT longest_match +longest_match + STMFD sp!, {r4-r9,fp,lr} + + LDR fp, [pc, #|__prev|-.-8] + + LDR r1, [pc, #|__max_chain_length|-.-8] + LDR r1, [r1] + LDR lr, [pc, #|__window|-.-8] + + LDR ip, [pc, #|__strstart|-.-8] + LDR ip, [ip] + ADD r2, lr, ip + LDR r5, [pc, #|__prev_length|-.-8] + LDR r5, [r5] + SUBS ip, ip, #MAX_DIST-250 ; if r6 > MAX_DIST + SUBCSS r6, ip, #250 ; r6 = r6 - MAXDIST + MOVLS r6, #0 ; else r6 = 0 + + ADD r7, r2, #MAX_MATCH-256 + ADD r7, r7, #256 ; r7 = r2 + MAX_MATCH (=258); + + SUB ip, r5, #1 + LDRB r8, [r2, ip] + LDRB r9, [r2, r5] + + LDR ip, [pc, #|__good_match|-.-8] + LDR ip, [ip] + CMP r5, ip + MOVCS r1, r1, LSR #2 + +cycle + ADD r3, lr, r0 + + LDRB ip, [r3, r5] + CMP ip, r9 + BNE cycle_end + + SUB ip, r5, #1 + LDRB ip, [r3, ip] + CMP ip, r8 + BNE cycle_end + + LDRB ip, [r2] + LDRB r4, [r3] + CMP ip, r4 + BNE cycle_end + + LDRB ip, [r3, #1] + LDRB r4, [r2, #1] + CMP ip, r4 + BNE cycle_end + + ADD r2, r2, #2 + ADD r3, r3, #2 + +inn_cycle + LDRB ip, [r2, #1]! + LDRB r4, [r3, #1]! + CMP ip, r4 + BNE exit_inn_cycle + + LDRB ip, [r2, #1]! + LDRB r4, [r3, #1]! + CMP ip, r4 + BNE exit_inn_cycle + + LDRB ip, [r2, #1]! + LDRB r4, [r3, #1]! + CMP ip, r4 + BNE exit_inn_cycle + + LDRB ip, [r2, #1]! + LDRB r4, [r3, #1]! + CMP ip, r4 + BNE exit_inn_cycle + + LDRB ip, [r2, #1]! + LDRB r4, [r3, #1]! + CMP ip, r4 + BNE exit_inn_cycle + + LDRB ip, [r2, #1]! + LDRB r4, [r3, #1]! + CMP ip, r4 + BNE exit_inn_cycle + + LDRB ip, [r2, #1]! + LDRB r4, [r3, #1]! + CMP ip, r4 + BNE exit_inn_cycle + + LDRB ip, [r2, #1]! + LDRB r4, [r3, #1]! + CMP ip, r4 + BNE exit_inn_cycle + + CMP r2, r7 + BCC inn_cycle + +exit_inn_cycle + SUB r4, r2, r7 ; len = MAX_MATCH - (int)(strend - scan); + ADD r4, r4, #MAX_MATCH-256 + ADD r4, r4, #256 + + SUB r2, r2, r4 ; scan = strend - MAX_MATCH + + CMP r4, r5 ; if (len > best_len) { + BLE cycle_end + + LDR ip, [pc, #|__match_start|-.-8] ; match_start = cur_match; + STR r0, [ip] + MOV r5, r4 ; best_len = len; + + LDR ip, [pc, #|__nice_match|-.-8] ; if (len >= nice_match) + LDR ip, [ip] + CMP r4, ip + BGE exit_match ; break; + + SUB ip, r5, #1 ; scan_end1 = scan[best_len-1]; + LDRB r8, [r2, ip] + LDRB r9, [r2, r5] ; scan_end = scan[best_len]; + +cycle_end + MOV ip, r0, LSL #17 ; cur_match & WMASK + MOV ip, ip, LSR #17 + + LDR r0, [fp, ip, ASL #1] ; cur_match = prev[cur_match & WMASK] + MOV r0, r0, ASL #16 + MOV r0, r0, LSR #16 + + CMP r0, r6 ; cur_match > limit + BLS exit_match + SUBS r1, r1, #1 ; --chain_length + BNE cycle ; chain_length != 0 + +exit_match + MOV r0, r5 + + LDMFD sp!, {r4-r9,fp,pc}^ + + END |