Commit 1f034456 authored by Geert Uytterhoeven's avatar Geert Uytterhoeven
Browse files

fbdev: c2p - Cleanups 



  - Improve comments and naming
  - Convert macros to static inline functions
  - Remove superfluous `break' after `return'
  - Make sure we get a build-time error (undefined reference to
    'c2p_unsupported') in case of future misuse
  - Replace `unsigned long' by `u32' in comp(), as that's what all callers use
  - Use {get,put}_unaligned_be32() in store_planar{,_masked}()
  - Use void * for arbitrary pointers
  - Use a union to represent pixels/words, to avoid casts

Signed-off-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
parent 8280eb8a

drivers/video/c2p.c

+96 −85
Original line number Diff line number Diff line 
/*

 *  Fast C2P (Chunky-to-Planar) Conversion

 *

 *  Copyright (C) 2003 Geert Uytterhoeven

 *  Copyright (C) 2003-2008 Geert Uytterhoeven

 *

 *  NOTES:

 *    - This code was inspired by Scout's C2P tutorial
@@ -14,6 +14,9 @@ 


#include <linux/module.h>

#include <linux/string.h>



#include <asm/unaligned.h>



#include "c2p.h"
@@ -21,97 +24,100 @@ 
     *  Basic transpose step

     */



#define _transp(d, i1, i2, shift, mask)				\

	do {							\

		u32 t = (d[i1] ^ (d[i2] >> shift)) & mask;	\

		d[i1] ^= t;					\

		d[i2] ^= t << shift;				\

	} while (0)

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 inline u32 get_mask(int n)

static inline u32 get_mask(unsigned int n)

{

	switch (n) {

	case 1:

		return 0x55555555;

		break;



	case 2:

		return 0x33333333;

		break;



	case 4:

		return 0x0f0f0f0f;

		break;



	case 8:

		return 0x00ff00ff;

		break;



	case 16:

		return 0x0000ffff;

		break;

	}



	c2p_unsupported();

	return 0;

}



#define transp_nx1(d, n)					\

	do {							\

		u32 mask = get_mask(n);				\

		/* First block */				\

		_transp(d, 0, 1, n, mask);			\

		/* Second block */				\

		_transp(d, 2, 3, n, mask);			\

		/* Third block */				\

		_transp(d, 4, 5, n, mask);			\

		/* Fourth block */				\

		_transp(d, 6, 7, n, mask);			\

	} while (0)



#define transp_nx2(d, n)					\

	do {							\

		u32 mask = get_mask(n);				\

		/* First block */				\

		_transp(d, 0, 2, n, mask);			\

		_transp(d, 1, 3, n, mask);			\

		/* Second block */				\

		_transp(d, 4, 6, n, mask);			\

		_transp(d, 5, 7, n, mask);			\

	} while (0)



#define transp_nx4(d, n)					\

	do {							\

		u32 mask = get_mask(n);				\

		_transp(d, 0, 4, n, mask);			\

		_transp(d, 1, 5, n, mask);			\

		_transp(d, 2, 6, n, mask);			\

		_transp(d, 3, 7, n, mask);			\

	} while (0)



#define transp(d, n, m)	transp_nx ## m(d, n)

static 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();

}





    /*

     *  Perform a full C2P step on 32 8-bit pixels, stored in 8 32-bit words

     *  containing

     *    - 32 8-bit chunky pixels on input

     *    - permuted planar data on output

     *    - permutated planar data (1 plane per 32-bit word) on output

     */



static void c2p_8bpp(u32 d[8])

static void c2p_32x8(u32 d[8])

{

	transp(d, 16, 4);

	transp(d, 8, 2);

	transp(d, 4, 1);

	transp(d, 2, 4);

	transp(d, 1, 2);

	transp8(d, 16, 4);

	transp8(d, 8, 2);

	transp8(d, 4, 1);

	transp8(d, 2, 4);

	transp8(d, 1, 2);

}





    /*

     *  Array containing the permution indices of the planar data after c2p

     *  Array containing the permutation indices of the planar data after c2p

     */



static const int perm_c2p_8bpp[8] = { 7, 5, 3, 1, 6, 4, 2, 0 };

static const int perm_c2p_32x8[8] = { 7, 5, 3, 1, 6, 4, 2, 0 };





    /*
@@ -119,8 +125,7 @@ static const int perm_c2p_8bpp[8] = { 7, 5, 3, 1, 6, 4, 2, 0 }; 
     *  This is equivalent to (a & mask) | (b & ~mask)

     */



static inline unsigned long comp(unsigned long a, unsigned long b,

				 unsigned long mask)

static inline u32 comp(u32 a, u32 b, u32 mask)

{

	return ((a ^ b) & mask) ^ b;

}
@@ -130,12 +135,12 @@ static inline unsigned long comp(unsigned long a, unsigned long b, 
     *  Store a full block of planar data after c2p conversion

     */



static inline void store_planar(char *dst, u32 dst_inc, u32 bpp, u32 d[8])

static inline void store_planar(void *dst, u32 dst_inc, u32 bpp, u32 d[8])

{

	int i;



	for (i = 0; i < bpp; i++, dst += dst_inc)

		*(u32 *)dst = d[perm_c2p_8bpp[i]];

		put_unaligned_be32(d[perm_c2p_32x8[i]], dst);

}
@@ -143,13 +148,15 @@ static inline void store_planar(char *dst, u32 dst_inc, u32 bpp, u32 d[8]) 
     *  Store a partial block of planar data after c2p conversion

     */



static inline void store_planar_masked(char *dst, u32 dst_inc, u32 bpp,

static inline void store_planar_masked(void *dst, u32 dst_inc, u32 bpp,

				       u32 d[8], u32 mask)

{

	int i;



	for (i = 0; i < bpp; i++, dst += dst_inc)

		*(u32 *)dst = comp(d[perm_c2p_8bpp[i]], *(u32 *)dst, mask);

		put_unaligned_be32(comp(d[perm_c2p_32x8[i]],

					get_unaligned_be32(dst), mask),

				   dst);

}
@@ -166,18 +173,21 @@ static inline void store_planar_masked(char *dst, u32 dst_inc, u32 bpp, 
     *  @bpp: Bits per pixel of the planar frame buffer (1-8)

     */



void c2p(u8 *dst, const u8 *src, u32 dx, u32 dy, u32 width, u32 height,

void c2p(void *dst, const void *src, u32 dx, u32 dy, u32 width, u32 height,

	 u32 dst_nextline, u32 dst_nextplane, u32 src_nextline, u32 bpp)

{

	int dst_idx;

	u32 d[8], first, last, w;

	union {

		u8 pixels[32];

		u32 words[8];

	} d;

	u32 dst_idx, first, last, w;

	const u8 *c;

	u8 *p;

	void *p;



	dst += dy*dst_nextline+(dx & ~31);

	dst_idx = dx % 32;

	first = ~0UL >> dst_idx;

	last = ~(~0UL >> ((dst_idx+width) % 32));

	first = 0xffffffffU >> dst_idx;

	last = ~(0xffffffffU >> ((dst_idx+width) % 32));

	while (height--) {

		c = src;

		p = dst;
@@ -185,11 +195,12 @@ void c2p(u8 *dst, const u8 *src, u32 dx, u32 dy, u32 width, u32 height, 
		if (dst_idx+width <= 32) {

			/* Single destination word */

			first &= last;

			memset(d, 0, sizeof(d));

			memcpy((u8 *)d+dst_idx, c, width);

			memset(d.pixels, 0, sizeof(d));

			memcpy(d.pixels+dst_idx, c, width);

			c += width;

			c2p_8bpp(d);

			store_planar_masked(p, dst_nextplane, bpp, d, first);

			c2p_32x8(d.words);

			store_planar_masked(p, dst_nextplane, bpp, d.words,

					    first);

			p += 4;

		} else {

			/* Multiple destination words */
@@ -197,32 +208,32 @@ void c2p(u8 *dst, const u8 *src, u32 dx, u32 dy, u32 width, u32 height, 
			/* Leading bits */

			if (dst_idx) {

				w = 32 - dst_idx;

				memset(d, 0, dst_idx);

				memcpy((u8 *)d+dst_idx, c, w);

				memset(d.pixels, 0, dst_idx);

				memcpy(d.pixels+dst_idx, c, w);

				c += w;

				c2p_8bpp(d);

				store_planar_masked(p, dst_nextplane, bpp, d,

						    first);

				c2p_32x8(d.words);

				store_planar_masked(p, dst_nextplane, bpp,

						    d.words, first);

				p += 4;

				w = width-w;

			}

			/* Main chunk */

			while (w >= 32) {

				memcpy(d, c, 32);

				memcpy(d.pixels, c, 32);

				c += 32;

				c2p_8bpp(d);

				store_planar(p, dst_nextplane, bpp, d);

				c2p_32x8(d.words);

				store_planar(p, dst_nextplane, bpp, d.words);

				p += 4;

				w -= 32;

			}

			/* Trailing bits */

			w %= 32;

			if (w > 0) {

				memcpy(d, c, w);

				memset((u8 *)d+w, 0, 32-w);

				c2p_8bpp(d);

				store_planar_masked(p, dst_nextplane, bpp, d,

						    last);

				memcpy(d.pixels, c, w);

				memset(d.pixels+w, 0, 32-w);

				c2p_32x8(d.words);

				store_planar_masked(p, dst_nextplane, bpp,

						    d.words, last);

			}

		}

		src += src_nextline;

drivers/video/c2p.h

+3 −3
Original line number Diff line number Diff line
@@ -10,7 +10,7 @@ 


#include <linux/types.h>



extern void c2p(u8 *dst, const u8 *src, u32 dx, u32 dy, u32 width, u32 height,

		u32 dst_nextline, u32 dst_nextplane, u32 src_nextline,

		u32 bpp);

extern void c2p(void *dst, const void *src, u32 dx, u32 dy, u32 width,

		u32 height, u32 dst_nextline, u32 dst_nextplane,

		u32 src_nextline, u32 bpp);

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