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Patch #5219 by Antonius Hellmann. Several optimisations to libmad. Both Coldfire and ARM targets should benefit much from this.

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@9821 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Thom Johansen 2006-04-27 19:52:09 +00:00
parent 103ebf77ce
commit f004315105
4 changed files with 1292 additions and 1098 deletions
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79
apps/codecs/libmad/bit.c
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@ -87,9 +87,8 @@ unsigned short const crc_table[256] = {
*/
void mad_bit_init(struct mad_bitptr *bitptr, unsigned char const *byte)
{
bitptr->byte = byte;
bitptr->cache = 0;
bitptr->left = CHAR_BIT;
bitptr->ptr = (unsigned long*)((long)byte & ~3);
bitptr->readbit = ((unsigned long)byte & 3) << 3;
}
/*
@ -99,17 +98,20 @@ void mad_bit_init(struct mad_bitptr *bitptr, unsigned char const *byte)
unsigned int mad_bit_length(struct mad_bitptr const *begin,
struct mad_bitptr const *end)
{
return begin->left +
CHAR_BIT * (end->byte - (begin->byte + 1)) + (CHAR_BIT - end->left);
return end->readbit - begin->readbit;
}
unsigned char mad_bit_bitsleft(struct mad_bitptr const *bitptr)
{
return 8 - (bitptr->readbit & 7);
}
/*
* NAME: bit->nextbyte()
* DESCRIPTION: return pointer to next unprocessed byte
*/
unsigned char const *mad_bit_nextbyte(struct mad_bitptr const *bitptr)
{
return bitptr->left == CHAR_BIT ? bitptr->byte : bitptr->byte + 1;
return (unsigned char const*)bitptr->ptr + ((bitptr->readbit + 7) >> 3);
}
/*
@ -118,60 +120,43 @@ unsigned char const *mad_bit_nextbyte(struct mad_bitptr const *bitptr)
*/
void mad_bit_skip(struct mad_bitptr *bitptr, unsigned int len)
{
bitptr->byte += len / CHAR_BIT;
bitptr->left -= len % CHAR_BIT;
if (bitptr->left > CHAR_BIT) {
bitptr->byte++;
bitptr->left += CHAR_BIT;
}
if (bitptr->left < CHAR_BIT)
bitptr->cache = *bitptr->byte;
bitptr->readbit += len;
}
/*
* NAME: bit->read()
* DESCRIPTION: read an arbitrary number of bits and return their UIMSBF value
*/
unsigned long bmask[] ICONST_ATTR =
{ 0x00000000, 0x00000001, 0x00000003, 0x00000007, 0x0000000f, 0x0000001f,
0x0000003f, 0x0000007f, 0x000000ff, 0x000001ff, 0x000003ff, 0x000007ff,
0x00000fff, 0x00001fff, 0x00003fff, 0x00007fff, 0x0000ffff, 0x0001ffff,
0x0003ffff, 0x0007ffff, 0x000fffff, 0x001fffff, 0x003fffff, 0x007fffff,
0x00ffffff, 0x01ffffff, 0x03ffffff, 0x07ffffff, 0x0fffffff, 0x1fffffff,
0x3fffffff, 0x7fffffff, 0xffffffff };
unsigned long mad_bit_read(struct mad_bitptr *bitptr, unsigned int len) ICODE_ATTR;
unsigned long mad_bit_read(struct mad_bitptr *bitptr, unsigned int len)
{
register unsigned long value;
unsigned long *curr = &bitptr->ptr[bitptr->readbit>>5];
if (bitptr->left == CHAR_BIT)
bitptr->cache = *bitptr->byte;
if(len)
{
if((bitptr->readbit ^ (bitptr->readbit + len - 1)) < 32)
{
bitptr->readbit += len;
if (len < bitptr->left) {
value = (bitptr->cache & ((1 << bitptr->left) - 1)) >>
(bitptr->left - len);
bitptr->left -= len;
return (betoh32(curr[0]) >> (-bitptr->readbit & 31)) & bmask[len];
}
else
{
bitptr->readbit += len;
return value;
return ((betoh32(curr[0]) << ( bitptr->readbit & 31))
+ (betoh32(curr[1]) >> (-bitptr->readbit & 31))) & bmask[len];
}
}
/* remaining bits in current byte */
value = bitptr->cache & ((1 << bitptr->left) - 1);
len -= bitptr->left;
bitptr->byte++;
bitptr->left = CHAR_BIT;
/* more bytes */
while (len >= CHAR_BIT) {
value = (value << CHAR_BIT) | *bitptr->byte++;
len -= CHAR_BIT;
}
if (len > 0) {
bitptr->cache = *bitptr->byte;
value = (value << len) | (bitptr->cache >> (CHAR_BIT - len));
bitptr->left -= len;
}
return value;
return 0;
}
# if 0