| /*************************************************************************** |
| * __________ __ ___. |
| * Open \______ \ ____ ____ | | _\_ |__ _______ ___ |
| * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / |
| * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < |
| * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ |
| * \/ \/ \/ \/ \/ |
| * $Id$ |
| * |
| * Copyright (C) 2008 by Jens Arnold |
| * |
| * based on arm_nrv2e_d8.S -- ARM decompressor for NRV2E |
| * Copyright (C) 1996-2008 Markus Franz Xaver Johannes Oberhumer |
| * Copyright (C) 1996-2008 Laszlo Molnar |
| * Copyright (C) 2000-2008 John F. Reiser |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * as published by the Free Software Foundation; either version 2 |
| * of the License, or (at your option) any later version. |
| * |
| * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY |
| * KIND, either express or implied. |
| * |
| ****************************************************************************/ |
| |
| #define src r4 |
| #define dst r5 |
| #define len r6 /* overlaps 'cnt' */ |
| #define cnt r6 /* overlaps 'len' while reading an offset */ |
| #define tmp r7 |
| |
| #define off r0 /* must be r0 because of indexed addressing */ |
| #define bits r1 |
| #define bitmask r2 |
| #define wrnk r3 /* -0x500 -M2_MAX_OFFSET before "wrinkle" */ |
| |
| |
| #define GETBIT \ |
| tst bits, bitmask; \ |
| bf 1f; \ |
| bsr get1_n2e; \ |
| 1: \ |
| shll bits /* using the delay slot on purpose */ |
| |
| #define getnextb(reg) GETBIT; rotcl reg |
| #define jnextb0 GETBIT; bf |
| #define jnextb1 GETBIT; bt |
| |
| .section .icode,"ax",@progbits |
| .align 2 |
| .global _ucl_nrv2e_decompress_8 |
| .type _ucl_nrv2e_decompress_8,@function |
| |
| /* src_len = ucl_nrv2e_decompress_8(const unsigned char *src, |
| * unsigned char *dst, |
| * unsigned long *dst_len) |
| */ |
| |
| _ucl_nrv2e_decompress_8: |
| sts.l pr, @-r15 |
| mov #-1, off ! off = -1 initial condition |
| mov.l r6, @-r15 |
| mov #-5, wrnk |
| mov.l r5, @-r15 |
| shll8 wrnk ! nrv2e -M2_MAX_OFFSET |
| mov.l r4, @-r15 |
| mov #-1, bitmask |
| shlr bitmask ! 0x7fffffff for testing before shifting |
| bra top_n2e |
| not bitmask, bits ! refill next time (MSB must be set) |
| |
| eof_n2e: |
| mov.l @r15+, r0 ! r0 = orig_src |
| mov.l @r15+, r1 ! r1 = orig_dst |
| sub r0, src |
| mov.l @r15+, r2 ! r2 = plen_dst |
| sub r1, dst |
| mov.l dst, @r2 |
| lds.l @r15+, pr |
| rts |
| mov src, r0 |
| |
| lit_n2e: |
| mov.b @src, tmp |
| add #1, src ! Need to fill the pipeline latency anyway |
| mov.b tmp, @dst |
| add #1, dst |
| top_n2e: |
| jnextb1 lit_n2e |
| bra getoff_n2e |
| mov #1, cnt |
| |
| off_n2e: |
| add #-1, cnt |
| getnextb(cnt) |
| getoff_n2e: |
| getnextb(cnt) |
| jnextb0 off_n2e |
| |
| mov cnt, tmp |
| mov #0, len ! cnt and len share a reg! |
| add #-3, tmp |
| cmp/pz tmp |
| bf offprev_n2e ! cnt was 2 |
| mov.b @src+, off ! low 7+1 bits |
| shll8 tmp |
| extu.b off, off |
| or tmp, off |
| not off, off ! off = ~off |
| tst off, off |
| bt eof_n2e |
| shar off |
| bt lenlast_n2e |
| bra lenmore_n2e |
| mov #1, len |
| |
| offprev_n2e: |
| jnextb1 lenlast_n2e |
| mov #1, len |
| lenmore_n2e: |
| jnextb1 lenlast_n2e |
| len_n2e: |
| getnextb(len) |
| jnextb0 len_n2e |
| bra gotlen_n2e |
| add #6-2, len |
| |
| get1_n2e: ! in: T bit set |
| mov.b @src+, bits ! SH1 sign-extends on load |
| rotcl bits ! LSB = T, T = MSB |
| shll16 bits |
| rts |
| shll8 bits |
| |
| lenlast_n2e: |
| getnextb(len) ! 0,1,2,3 |
| add #2, len |
| gotlen_n2e: |
| cmp/gt off, wrnk |
| movt tmp ! too far away, so minimum match length is 3 |
| add tmp, len |
| copy_n2e: |
| mov.b @(off,dst), tmp |
| add #-1, len |
| mov.b tmp, @dst |
| add #1, dst |
| tst len, len |
| bf copy_n2e |
| bra top_n2e |
| nop |
| |
| .size ucl_nrv2e_decompress_8, .-ucl_nrv2e_decompress_8 |