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Self-extractor for on-disk firmware image: UCL decompressor in SH1 assembler - less than half the size of the compiled C function, and ~45% faster.

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@18904 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Jens Arnold 2008-10-28 21:07:53 +00:00
parent afd2f681d1
commit 2c52dee83f
3 changed files with 164 additions and 72 deletions
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69
firmware/decompressor/decompressor.c
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@ -36,8 +36,8 @@ extern char loadaddress[], dramend[];
extern void start(void);
void main(void) ICODE_ATTR;
static int ucl_nrv2e_decompress_8(const unsigned char *src, unsigned char *dst,
unsigned long *dst_len) ICODE_ATTR;
int ucl_nrv2e_decompress_8(const unsigned char *src, unsigned char *dst,
unsigned long *dst_len) ICODE_ATTR;
/* Vector table */
void (*vbr[]) (void) __attribute__ ((section (".vectors"))) =
@ -50,71 +50,6 @@ void (*vbr[]) (void) __attribute__ ((section (".vectors"))) =
/** All subsequent functions are executed from IRAM **/
/* Thinned out version of the UCL 2e decompression sourcecode
* Original (C) Markus F.X.J Oberhumer under GNU GPL license */
#define GETBIT(bb, src, ilen) \
(((bb = bb & 0x7f ? bb*2 : ((unsigned)src[ilen++]*2+1)) >> 8) & 1)
static int ucl_nrv2e_decompress_8(const unsigned char *src, unsigned char *dst,
unsigned long *dst_len)
{
unsigned long bb = 0;
unsigned ilen = 0, olen = 0, last_m_off = 1;
for (;;)
{
unsigned m_off, m_len;
while (GETBIT(bb,src,ilen))
dst[olen++] = src[ilen++];
m_off = 1;
for (;;)
{
m_off = m_off*2 + GETBIT(bb,src,ilen);
if (GETBIT(bb,src,ilen))
break;
m_off = (m_off-1)*2 + GETBIT(bb,src,ilen);
}
if (m_off == 2)
{
m_off = last_m_off;
m_len = GETBIT(bb,src,ilen);
}
else
{
m_off = (m_off-3)*256 + src[ilen++];
if (m_off == 0xffffffff)
break;
m_len = (m_off ^ 0xffffffff) & 1;
m_off >>= 1;
last_m_off = ++m_off;
}
if (m_len)
m_len = 1 + GETBIT(bb,src,ilen);
else if (GETBIT(bb,src,ilen))
m_len = 3 + GETBIT(bb,src,ilen);
else
{
m_len++;
do {
m_len = m_len*2 + GETBIT(bb,src,ilen);
} while (!GETBIT(bb,src,ilen));
m_len += 3;
}
m_len += (m_off > 0x500);
{
const unsigned char *m_pos;
m_pos = dst + olen - m_off;
dst[olen++] = *m_pos++;
do dst[olen++] = *m_pos++; while (--m_len > 0);
}
}
*dst_len = olen;
return ilen;
}
#define ALIGNED_IMG_SIZE ((sizeof(image) + 3) & ~3)
/* This will never return */
void main(void)