154 строки
2.7 KiB
C
154 строки
2.7 KiB
C
/*
|
|
* Fast C2P (Chunky-to-Planar) Conversion
|
|
*
|
|
* Copyright (C) 2003-2008 Geert Uytterhoeven
|
|
*
|
|
* NOTES:
|
|
* - This code was inspired by Scout's C2P tutorial
|
|
* - It assumes to run on a big endian system
|
|
*
|
|
* This file is subject to the terms and conditions of the GNU General Public
|
|
* License. See the file COPYING in the main directory of this archive
|
|
* for more details.
|
|
*/
|
|
|
|
|
|
/*
|
|
* Basic transpose step
|
|
*/
|
|
|
|
static inline void _transp(u32 d[], unsigned int i1, unsigned int i2,
|
|
unsigned int shift, u32 mask)
|
|
{
|
|
u32 t = (d[i1] ^ (d[i2] >> shift)) & mask;
|
|
|
|
d[i1] ^= t;
|
|
d[i2] ^= t << shift;
|
|
}
|
|
|
|
|
|
extern void c2p_unsupported(void);
|
|
|
|
static __always_inline u32 get_mask(unsigned int n)
|
|
{
|
|
switch (n) {
|
|
case 1:
|
|
return 0x55555555;
|
|
|
|
case 2:
|
|
return 0x33333333;
|
|
|
|
case 4:
|
|
return 0x0f0f0f0f;
|
|
|
|
case 8:
|
|
return 0x00ff00ff;
|
|
|
|
case 16:
|
|
return 0x0000ffff;
|
|
}
|
|
|
|
c2p_unsupported();
|
|
return 0;
|
|
}
|
|
|
|
|
|
/*
|
|
* Transpose operations on 8 32-bit words
|
|
*/
|
|
|
|
static __always_inline void transp8(u32 d[], unsigned int n, unsigned int m)
|
|
{
|
|
u32 mask = get_mask(n);
|
|
|
|
switch (m) {
|
|
case 1:
|
|
/* First n x 1 block */
|
|
_transp(d, 0, 1, n, mask);
|
|
/* Second n x 1 block */
|
|
_transp(d, 2, 3, n, mask);
|
|
/* Third n x 1 block */
|
|
_transp(d, 4, 5, n, mask);
|
|
/* Fourth n x 1 block */
|
|
_transp(d, 6, 7, n, mask);
|
|
return;
|
|
|
|
case 2:
|
|
/* First n x 2 block */
|
|
_transp(d, 0, 2, n, mask);
|
|
_transp(d, 1, 3, n, mask);
|
|
/* Second n x 2 block */
|
|
_transp(d, 4, 6, n, mask);
|
|
_transp(d, 5, 7, n, mask);
|
|
return;
|
|
|
|
case 4:
|
|
/* Single n x 4 block */
|
|
_transp(d, 0, 4, n, mask);
|
|
_transp(d, 1, 5, n, mask);
|
|
_transp(d, 2, 6, n, mask);
|
|
_transp(d, 3, 7, n, mask);
|
|
return;
|
|
}
|
|
|
|
c2p_unsupported();
|
|
}
|
|
|
|
|
|
/*
|
|
* Transpose operations on 4 32-bit words
|
|
*/
|
|
|
|
static __always_inline void transp4(u32 d[], unsigned int n, unsigned int m)
|
|
{
|
|
u32 mask = get_mask(n);
|
|
|
|
switch (m) {
|
|
case 1:
|
|
/* First n x 1 block */
|
|
_transp(d, 0, 1, n, mask);
|
|
/* Second n x 1 block */
|
|
_transp(d, 2, 3, n, mask);
|
|
return;
|
|
|
|
case 2:
|
|
/* Single n x 2 block */
|
|
_transp(d, 0, 2, n, mask);
|
|
_transp(d, 1, 3, n, mask);
|
|
return;
|
|
}
|
|
|
|
c2p_unsupported();
|
|
}
|
|
|
|
|
|
/*
|
|
* Transpose operations on 4 32-bit words (reverse order)
|
|
*/
|
|
|
|
static __always_inline void transp4x(u32 d[], unsigned int n, unsigned int m)
|
|
{
|
|
u32 mask = get_mask(n);
|
|
|
|
switch (m) {
|
|
case 2:
|
|
/* Single n x 2 block */
|
|
_transp(d, 2, 0, n, mask);
|
|
_transp(d, 3, 1, n, mask);
|
|
return;
|
|
}
|
|
|
|
c2p_unsupported();
|
|
}
|
|
|
|
|
|
/*
|
|
* Compose two values, using a bitmask as decision value
|
|
* This is equivalent to (a & mask) | (b & ~mask)
|
|
*/
|
|
|
|
static inline u32 comp(u32 a, u32 b, u32 mask)
|
|
{
|
|
return ((a ^ b) & mask) ^ b;
|
|
}
|