/* SPDX-License-Identifier: GPL-2.0-only * *  Generic bitmap / 8 bpp image bitstreamer for packed pixel framebuffers * *	Rewritten by: *	Copyright (C)  2025 Zsolt Kajtar (soci@c64.rulez.org) * *	Based on previous work of: *	Copyright (C)  June 1999 James Simmons *	Anton Vorontsov <avorontsov@ru.mvista.com> *	Pavel Pisa <pisa@cmp.felk.cvut.cz> *	Antonino A. Daplas <adaplas@gmail.com> *	and others * * NOTES: * * Handles native and foreign byte order on both endians, standard and * reverse pixel order in a byte (<8 BPP), word length of 32/64 bits, * bits per pixel from 1 to the word length. Handles line lengths at byte * granularity while maintaining aligned accesses. * * Optimized routines for word aligned 1, 2, 4 pixel per word for high * bpp modes and 4 pixel at a time operation for low bpp. * * The color image is expected to be one byte per pixel, and values should * not exceed the bitdepth or the pseudo palette (if used). */#include "fb_draw.h" /* bitmap image iterator, one pixel at a time */struct fb_bitmap_iter {	const u8 *data;	unsigned long colors[2];	int width, i;}; static bool fb_bitmap_image(void *iterator, unsigned long *pixels, int *bits){	struct fb_bitmap_iter *iter = iterator; 	if (iter->i < iter->width) {		int bit = ~iter->i & (BITS_PER_BYTE-1);		int byte = iter->i++ / BITS_PER_BYTE; 		*pixels = iter->colors[(iter->data[byte] >> bit) & 1];		return true;	}	iter->data += BITS_TO_BYTES(iter->width);	iter->i = 0;	return false;} /* color image iterator, one pixel at a time */struct fb_color_iter {	const u8 *data;	const u32 *palette;	struct fb_reverse reverse;	int shift;	int width, i;}; static bool fb_color_image(void *iterator, unsigned long *pixels, int *bits){	struct fb_color_iter *iter = iterator; 	if (iter->i < iter->width) {		unsigned long color = iter->data[iter->i++]; 		if (iter->palette)			color = iter->palette[color];		*pixels = color << iter->shift;		if (iter->reverse.pixel)			*pixels = fb_reverse_bits_long(*pixels);		return true;	}	iter->data += iter->width;	iter->i = 0;	return false;} /* bitmap image iterator, 4 pixels at a time */struct fb_bitmap4x_iter {	const u8 *data;	u32 fgxcolor, bgcolor;	int width, i;	const u32 *expand;	int bpp;	bool top;}; static bool fb_bitmap4x_image(void *iterator, unsigned long *pixels, int *bits){	struct fb_bitmap4x_iter *iter = iterator;	u8 data; 	if (iter->i >= BITS_PER_BYTE/2) {		iter->i -= BITS_PER_BYTE/2;		iter->top = !iter->top;		if (iter->top)			data = *iter->data++ >> BITS_PER_BYTE/2;		else			data = iter->data[-1] & ((1 << BITS_PER_BYTE/2)-1);	} else if (iter->i != 0) {		*bits = iter->bpp * iter->i;		if (iter->top)			data = iter->data[-1] & ((1 << BITS_PER_BYTE/2)-1);		else			data = *iter->data++ >> BITS_PER_BYTE/2;#ifndef __LITTLE_ENDIAN		data >>= BITS_PER_BYTE/2 - iter->i;#endif		iter->i = 0;	} else {		*bits = iter->bpp * BITS_PER_BYTE/2;		iter->i = iter->width;		iter->top = false;		return false;	}	*pixels = (iter->fgxcolor & iter->expand[data]) ^ iter->bgcolor;#ifndef __LITTLE_ENDIAN	*pixels <<= BITS_PER_LONG - *bits;#endif	return true;} /* draw a line a group of pixels at a time */static __always_inline void fb_bitblit(bool (*get)(void *iter, unsigned long *pixels,						   int *bits),				       void *iter, int bits, struct fb_address *dst,				       struct fb_reverse reverse){	unsigned long pixels, val, mask, old;	int offset = 0;	int shift = dst->bits; 	if (shift) {		old = fb_read_offset(0, dst);		val = fb_reverse_long(old, reverse);		val &= ~fb_right(~0UL, shift);	} else {		old = 0;		val = 0;	} 	while (get(iter, &pixels, &bits)) {		val |= fb_right(pixels, shift);		shift += bits; 		if (shift < BITS_PER_LONG)			continue; 		val = fb_reverse_long(val, reverse);		fb_write_offset(val, offset++, dst);		shift &= BITS_PER_LONG - 1;		val = !shift ? 0 : fb_left(pixels, bits - shift);	} 	if (shift) {		mask = ~fb_pixel_mask(shift, reverse);		val = fb_reverse_long(val, reverse);		if (offset || !dst->bits)			old = fb_read_offset(offset, dst);		fb_write_offset(fb_comp(val, old, mask), offset, dst);	}} /* draw a color image a pixel at a time */static inline void fb_color_imageblit(const struct fb_image *image, struct fb_address *dst,				      unsigned int bits_per_line, const u32 *palette, int bpp,				      struct fb_reverse reverse){	struct fb_color_iter iter;	u32 height; 	iter.data = (const u8 *)image->data;	iter.palette = palette;	iter.reverse = reverse;#ifdef __LITTLE_ENDIAN	if (reverse.pixel)		iter.shift = BITS_PER_BYTE - bpp;	else		iter.shift = 0;#else	if (reverse.pixel)		iter.shift = BITS_PER_LONG - BITS_PER_BYTE;	else		iter.shift = BITS_PER_LONG - bpp;#endif	iter.width = image->width;	iter.i = 0; 	height = image->height;	while (height--) {		fb_bitblit(fb_color_image, &iter, bpp, dst, reverse);		fb_address_forward(dst, bits_per_line);	}} #ifdef __LITTLE_ENDIAN#define FB_GEN(a, b) (((a)/8+(((a)&4)<<((b)-2)) \		       +(((a)&2)<<((b)*2-1))+(((a)&1u)<<((b)*3)))*((1<<(b))-1))#define FB_GEN1(a) ((a)/8+((a)&4)/2+((a)&2)*2+((a)&1)*8)#else#define FB_GEN(a, b) (((((a)/8)<<((b)*3))+(((a)&4)<<((b)*2-2)) \		       +(((a)&2)<<(b-1))+((a)&1u))*((1<<(b))-1))#define FB_GEN1(a) (a)#endif #define FB_GENx(a) { FB_GEN(0, (a)), FB_GEN(1, (a)), FB_GEN(2, (a)), FB_GEN(3, (a)),	\	FB_GEN(4, (a)), FB_GEN(5, (a)), FB_GEN(6, (a)), FB_GEN(7, (a)),			\	FB_GEN(8, (a)), FB_GEN(9, (a)), FB_GEN(10, (a)), FB_GEN(11, (a)),		\	FB_GEN(12, (a)), FB_GEN(13, (a)), FB_GEN(14, (a)), FB_GEN(15, (a)) } /* draw a 2 color image four pixels at a time (for 1-8 bpp only) */static inline void fb_bitmap4x_imageblit(const struct fb_image *image, struct fb_address *dst,					 unsigned long fgcolor, unsigned long bgcolor, int bpp,					 unsigned int bits_per_line, struct fb_reverse reverse){	static const u32 mul[BITS_PER_BYTE] = {		0xf, 0x55, 0x249, 0x1111, 0x8421, 0x41041, 0x204081, 0x01010101	};	static const u32 expand[BITS_PER_BYTE][1 << 4] = {		{			FB_GEN1(0), FB_GEN1(1), FB_GEN1(2), FB_GEN1(3),			FB_GEN1(4), FB_GEN1(5), FB_GEN1(6), FB_GEN1(7),			FB_GEN1(8), FB_GEN1(9), FB_GEN1(10), FB_GEN1(11),			FB_GEN1(12), FB_GEN1(13), FB_GEN1(14), FB_GEN1(15)		},		FB_GENx(2), FB_GENx(3), FB_GENx(4),		FB_GENx(5), FB_GENx(6), FB_GENx(7), FB_GENx(8),	};	struct fb_bitmap4x_iter iter;	u32 height; 	iter.data = (const u8 *)image->data;	if (reverse.pixel) {		fgcolor = fb_reverse_bits_long(fgcolor << (BITS_PER_BYTE - bpp));		bgcolor = fb_reverse_bits_long(bgcolor << (BITS_PER_BYTE - bpp));	}	iter.fgxcolor = (fgcolor ^ bgcolor) * mul[bpp-1];	iter.bgcolor = bgcolor * mul[bpp-1];	iter.width = image->width;	iter.i = image->width;	iter.expand = expand[bpp-1];	iter.bpp = bpp;	iter.top = false; 	height = image->height;	while (height--) {		fb_bitblit(fb_bitmap4x_image, &iter, bpp * BITS_PER_BYTE/2, dst, reverse);		fb_address_forward(dst, bits_per_line);	}} /* draw a bitmap image 1 pixel at a time (for >8 bpp) */static inline void fb_bitmap1x_imageblit(const struct fb_image *image, struct fb_address *dst,					 unsigned long fgcolor, unsigned long bgcolor, int bpp,					 unsigned int bits_per_line, struct fb_reverse reverse){	struct fb_bitmap_iter iter;	u32 height; 	iter.colors[0] = bgcolor;	iter.colors[1] = fgcolor;#ifndef __LITTLE_ENDIAN	iter.colors[0] <<= BITS_PER_LONG - bpp;	iter.colors[1] <<= BITS_PER_LONG - bpp;#endif	iter.data = (const u8 *)image->data;	iter.width = image->width;	iter.i = 0; 	height = image->height;	while (height--) {		fb_bitblit(fb_bitmap_image, &iter, bpp, dst, reverse);		fb_address_forward(dst, bits_per_line);	}} /* one pixel per word, 64/32 bpp blitting */static inline void fb_bitmap_1ppw(const struct fb_image *image, struct fb_address *dst,				  unsigned long fgcolor, unsigned long bgcolor,				  int words_per_line, struct fb_reverse reverse){	unsigned long tab[2];	const u8 *src = (u8 *)image->data;	int width = image->width;	int offset;	u32 height; 	if (reverse.byte) {		tab[0] = swab_long(bgcolor);		tab[1] = swab_long(fgcolor);	} else {		tab[0] = bgcolor;		tab[1] = fgcolor;	} 	height = image->height;	while (height--) {		for (offset = 0; offset + 8 <= width; offset += 8) {			unsigned int srcbyte = *src++; 			fb_write_offset(tab[(srcbyte >> 7) & 1], offset + 0, dst);			fb_write_offset(tab[(srcbyte >> 6) & 1], offset + 1, dst);			fb_write_offset(tab[(srcbyte >> 5) & 1], offset + 2, dst);			fb_write_offset(tab[(srcbyte >> 4) & 1], offset + 3, dst);			fb_write_offset(tab[(srcbyte >> 3) & 1], offset + 4, dst);			fb_write_offset(tab[(srcbyte >> 2) & 1], offset + 5, dst);			fb_write_offset(tab[(srcbyte >> 1) & 1], offset + 6, dst);			fb_write_offset(tab[(srcbyte >> 0) & 1], offset + 7, dst);		} 		if (offset < width) {			unsigned int srcbyte = *src++; 			while (offset < width) {				fb_write_offset(tab[(srcbyte >> 7) & 1], offset, dst);				srcbyte <<= 1;				offset++;			}		}		fb_address_move_long(dst, words_per_line);	}} static inline unsigned long fb_pack(unsigned long left, unsigned long right, int bits){#ifdef __LITTLE_ENDIAN	return left | right << bits;#else	return right | left << bits;#endif} /* aligned 32/16 bpp blitting */static inline void fb_bitmap_2ppw(const struct fb_image *image, struct fb_address *dst,				  unsigned long fgcolor, unsigned long bgcolor,				  int words_per_line, struct fb_reverse reverse){	unsigned long tab[4];	const u8 *src = (u8 *)image->data;	int width = image->width / 2;	int offset;	u32 height; 	tab[0] = fb_pack(bgcolor, bgcolor, BITS_PER_LONG/2);	tab[1] = fb_pack(bgcolor, fgcolor, BITS_PER_LONG/2);	tab[2] = fb_pack(fgcolor, bgcolor, BITS_PER_LONG/2);	tab[3] = fb_pack(fgcolor, fgcolor, BITS_PER_LONG/2); 	if (reverse.byte) {		tab[0] = swab_long(tab[0]);		tab[1] = swab_long(tab[1]);		tab[2] = swab_long(tab[2]);		tab[3] = swab_long(tab[3]);	} 	height = image->height;	while (height--) {		for (offset = 0; offset + 4 <= width; offset += 4) {			unsigned int srcbyte = *src++; 			fb_write_offset(tab[(srcbyte >> 6) & 3], offset + 0, dst);			fb_write_offset(tab[(srcbyte >> 4) & 3], offset + 1, dst);			fb_write_offset(tab[(srcbyte >> 2) & 3], offset + 2, dst);			fb_write_offset(tab[(srcbyte >> 0) & 3], offset + 3, dst);		} 		if (offset < width) {			unsigned int srcbyte = *src++; 			while (offset < width) {				fb_write_offset(tab[(srcbyte >> 6) & 3], offset, dst);				srcbyte <<= 2;				offset++;			}		}		fb_address_move_long(dst, words_per_line);	}} #define FB_PATP(a, b) (((a)<<((b)*BITS_PER_LONG/4))*((1UL<<BITS_PER_LONG/4)-1UL))#define FB_PAT4(a) (FB_PATP((a)&1, 0)|FB_PATP(((a)&2)/2, 1)| \	FB_PATP(((a)&4)/4, 2)|FB_PATP(((a)&8)/8, 3)) /* aligned 16/8 bpp blitting */static inline void fb_bitmap_4ppw(const struct fb_image *image, struct fb_address *dst,				  unsigned long fgcolor, unsigned long bgcolor,				  int words_per_line, struct fb_reverse reverse){	static const unsigned long tab16_be[] = {		0, FB_PAT4(1UL), FB_PAT4(2UL), FB_PAT4(3UL),		FB_PAT4(4UL), FB_PAT4(5UL), FB_PAT4(6UL), FB_PAT4(7UL),		FB_PAT4(8UL), FB_PAT4(9UL), FB_PAT4(10UL), FB_PAT4(11UL),		FB_PAT4(12UL), FB_PAT4(13UL), FB_PAT4(14UL), ~0UL	};	static const unsigned long tab16_le[] = {		0, FB_PAT4(8UL), FB_PAT4(4UL), FB_PAT4(12UL),		FB_PAT4(2UL), FB_PAT4(10UL), FB_PAT4(6UL), FB_PAT4(14UL),		FB_PAT4(1UL), FB_PAT4(9UL), FB_PAT4(5UL), FB_PAT4(13UL),		FB_PAT4(3UL), FB_PAT4(11UL), FB_PAT4(7UL), ~0UL	};	const unsigned long *tab;	const u8 *src = (u8 *)image->data;	int width = image->width / 4;	int offset;	u32 height; 	fgcolor = fgcolor | fgcolor << BITS_PER_LONG/4;	bgcolor = bgcolor | bgcolor << BITS_PER_LONG/4;	fgcolor = fgcolor | fgcolor << BITS_PER_LONG/2;	bgcolor = bgcolor | bgcolor << BITS_PER_LONG/2;	fgcolor ^= bgcolor; 	if (BITS_PER_LONG/4 > BITS_PER_BYTE && reverse.byte) {		fgcolor = swab_long(fgcolor);		bgcolor = swab_long(bgcolor);	} #ifdef __LITTLE_ENDIAN	tab = reverse.byte ? tab16_be : tab16_le;#else	tab = reverse.byte ? tab16_le : tab16_be;#endif 	height = image->height;	while (height--) {		for (offset = 0; offset + 2 <= width; offset += 2, src++) {			fb_write_offset((fgcolor & tab[*src >> 4]) ^ bgcolor, offset + 0, dst);			fb_write_offset((fgcolor & tab[*src & 0xf]) ^ bgcolor, offset + 1, dst);		} 		if (offset < width)			fb_write_offset((fgcolor & tab[*src++ >> 4]) ^ bgcolor, offset, dst); 		fb_address_move_long(dst, words_per_line);	}} static inline void fb_bitmap_imageblit(const struct fb_image *image, struct fb_address *dst,				       unsigned int bits_per_line, const u32 *palette, int bpp,				       struct fb_reverse reverse){	unsigned long fgcolor, bgcolor; 	if (palette) {		fgcolor = palette[image->fg_color];		bgcolor = palette[image->bg_color];	} else {		fgcolor = image->fg_color;		bgcolor = image->bg_color;	} 	if (!dst->bits && !(bits_per_line & (BITS_PER_LONG-1))) {		if (bpp == BITS_PER_LONG && BITS_PER_LONG == 32) {			fb_bitmap_1ppw(image, dst, fgcolor, bgcolor,				       bits_per_line / BITS_PER_LONG, reverse);			return;		}		if (bpp == BITS_PER_LONG/2 && !(image->width & 1)) {			fb_bitmap_2ppw(image, dst, fgcolor, bgcolor,				       bits_per_line / BITS_PER_LONG, reverse);			return;		}		if (bpp == BITS_PER_LONG/4 && !(image->width & 3)) {			fb_bitmap_4ppw(image, dst, fgcolor, bgcolor,				       bits_per_line / BITS_PER_LONG, reverse);			return;		}	} 	if (bpp > 0 && bpp <= BITS_PER_BYTE)		fb_bitmap4x_imageblit(image, dst, fgcolor, bgcolor, bpp,				     bits_per_line, reverse);	else if (bpp > BITS_PER_BYTE && bpp <= BITS_PER_LONG)		fb_bitmap1x_imageblit(image, dst, fgcolor, bgcolor, bpp,				     bits_per_line, reverse);} static inline void fb_imageblit(struct fb_info *p, const struct fb_image *image){	int bpp = p->var.bits_per_pixel;	unsigned int bits_per_line = BYTES_TO_BITS(p->fix.line_length);	struct fb_address dst = fb_address_init(p);	struct fb_reverse reverse = fb_reverse_init(p);	const u32 *palette = fb_palette(p); 	fb_address_forward(&dst, image->dy * bits_per_line + image->dx * bpp); 	if (image->depth == 1)		fb_bitmap_imageblit(image, &dst, bits_per_line, palette, bpp, reverse);	else		fb_color_imageblit(image, &dst, bits_per_line, palette, bpp, reverse);}