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/***************************************************************************
* __________ __ ___.
* 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 #-4, tmp ! T=1 on entry, so this does
addc cnt, tmp ! tmp = cnt - 3, T = (cnt >= 3)
mov #0, len ! cnt and len share a reg!
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
bf lenmore_n2e ! always taken if the preceding bt isn't
offprev_n2e:
jnextb1 lenlast_n2e
lenmore_n2e:
mov #1, len
jnextb1 lenlast_n2e
len_n2e:
getnextb(len)
jnextb0 len_n2e
bra gotlen_n2e
mov #6-2, tmp
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
mov #2, tmp
gotlen_n2e:
cmp/gt off, wrnk ! too far away, so minimum match length is 3
addc tmp, len
copy_n2e:
add #-1, len
mov.b @(off,dst), tmp
tst len, len
mov.b tmp, @dst
add #1, dst
bf copy_n2e
bt top_n2e ! always taken if the preceding bf isn't
.size ucl_nrv2e_decompress_8, .-ucl_nrv2e_decompress_8
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