--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/video/SDL_stretch.c	Thu Apr 26 16:45:43 2001 +0000
@@ -0,0 +1,312 @@
+/*
+    SDL - Simple DirectMedia Layer
+    Copyright (C) 1997, 1998, 1999, 2000, 2001  Sam Lantinga
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Library General Public
+    License as published by the Free Software Foundation; either
+    version 2 of the License, or (at your option) any later version.
+
+    This library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Library General Public License for more details.
+
+    You should have received a copy of the GNU Library General Public
+    License along with this library; if not, write to the Free
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+    Sam Lantinga
+    slouken@devolution.com
+*/
+
+#ifdef SAVE_RCSID
+static char rcsid =
+ "@(#) $Id$";
+#endif
+
+/* This a stretch blit implementation based on ideas given to me by
+   Tomasz Cejner - thanks! :)
+
+   April 27, 2000 - Sam Lantinga
+*/
+
+#include "SDL_error.h"
+#include "SDL_video.h"
+#include "SDL_blit.h"
+
+/* This isn't ready for general consumption yet - it should be folded
+   into the general blitting mechanism.
+*/
+
+#if (defined(WIN32) && !defined(_M_ALPHA) && !defined(_WIN32_WCE)) || \
+    defined(i386) && defined(__GNUC__) && defined(USE_ASMBLIT)
+#define USE_ASM_STRETCH
+#endif
+
+#ifdef USE_ASM_STRETCH
+
+#if defined(WIN32) || defined(i386)
+#define PREFIX16	0x66
+#define STORE_BYTE	0xAA
+#define STORE_WORD	0xAB
+#define LOAD_BYTE	0xAC
+#define LOAD_WORD	0xAD
+#define RETURN		0xC3
+#else
+#error Need assembly opcodes for this architecture
+#endif
+
+#if defined(__ELF__) && defined(__GNUC__)
+extern unsigned char _copy_row[4096] __attribute__ ((alias ("copy_row")));
+#endif
+static unsigned char copy_row[4096];
+
+static int generate_rowbytes(int src_w, int dst_w, int bpp)
+{
+	static struct {
+		int bpp;
+		int src_w;
+		int dst_w;
+	} last;
+
+	int i;
+	int pos, inc;
+	unsigned char *eip;
+	unsigned char load, store;
+
+	/* See if we need to regenerate the copy buffer */
+	if ( (src_w == last.src_w) &&
+	     (dst_w == last.src_w) && (bpp == last.bpp) ) {
+		return(0);
+	}
+	last.bpp = bpp;
+	last.src_w = src_w;
+	last.dst_w = dst_w;
+
+	switch (bpp) {
+	    case 1:
+		load = LOAD_BYTE;
+		store = STORE_BYTE;
+		break;
+	    case 2:
+	    case 4:
+		load = LOAD_WORD;
+		store = STORE_WORD;
+		break;
+	    default:
+		SDL_SetError("ASM stretch of %d bytes isn't supported\n", bpp);
+		return(-1);
+	}
+	pos = 0x10000;
+	inc = (src_w << 16) / dst_w;
+	eip = copy_row;
+	for ( i=0; i<dst_w; ++i ) {
+		while ( pos >= 0x10000L ) {
+			if ( bpp == 2 ) {
+				*eip++ = PREFIX16;
+			}
+			*eip++ = load;
+			pos -= 0x10000L;
+		}
+		if ( bpp == 2 ) {
+			*eip++ = PREFIX16;
+		}
+		*eip++ = store;
+		pos += inc;
+	}
+	*eip++ = RETURN;
+
+	/* Verify that we didn't overflow (too late) */
+	if ( eip > (copy_row+sizeof(copy_row)) ) {
+		SDL_SetError("Copy buffer overflow");
+		return(-1);
+	}
+	return(0);
+}
+
+#else
+
+#define DEFINE_COPY_ROW(name, type)			\
+void name(type *src, int src_w, type *dst, int dst_w)	\
+{							\
+	int i;						\
+	int pos, inc;					\
+	type pixel = 0;					\
+							\
+	pos = 0x10000;					\
+	inc = (src_w << 16) / dst_w;			\
+	for ( i=dst_w; i>0; --i ) {			\
+		while ( pos >= 0x10000L ) {		\
+			pixel = *src++;			\
+			pos -= 0x10000L;		\
+		}					\
+		*dst++ = pixel;				\
+		pos += inc;				\
+	}						\
+}
+DEFINE_COPY_ROW(copy_row1, Uint8)
+DEFINE_COPY_ROW(copy_row2, Uint16)
+DEFINE_COPY_ROW(copy_row4, Uint32)
+
+#endif /* USE_ASM_STRETCH */
+
+/* The ASM code doesn't handle 24-bpp stretch blits */
+void copy_row3(Uint8 *src, int src_w, Uint8 *dst, int dst_w)
+{
+	int i;
+	int pos, inc;
+	Uint8 pixel[3];
+
+	pos = 0x10000;
+	inc = (src_w << 16) / dst_w;
+	for ( i=dst_w; i>0; --i ) {
+		while ( pos >= 0x10000L ) {
+			pixel[0] = *src++;
+			pixel[1] = *src++;
+			pixel[2] = *src++;
+			pos -= 0x10000L;
+		}
+		*dst++ = pixel[0];
+		*dst++ = pixel[1];
+		*dst++ = pixel[2];
+		pos += inc;
+	}
+}
+
+/* Perform a stretch blit between two surfaces of the same format.
+   NOTE:  This function is not safe to call from multiple threads!
+*/
+int SDL_SoftStretch(SDL_Surface *src, SDL_Rect *srcrect,
+                    SDL_Surface *dst, SDL_Rect *dstrect)
+{
+	int pos, inc;
+	int dst_width;
+	int dst_maxrow;
+	int src_row, dst_row;
+	Uint8 *srcp = NULL;
+	Uint8 *dstp;
+	SDL_Rect full_src;
+	SDL_Rect full_dst;
+#if defined(USE_ASM_STRETCH) && defined(__GNUC__)
+	int u1, u2;
+#endif
+	const int bpp = dst->format->BytesPerPixel;
+
+	if ( src->format->BitsPerPixel != dst->format->BitsPerPixel ) {
+		SDL_SetError("Only works with same format surfaces");
+		return(-1);
+	}
+
+	/* Verify the blit rectangles */
+	if ( srcrect ) {
+		if ( (srcrect->x < 0) || (srcrect->y < 0) ||
+		     ((srcrect->x+srcrect->w) > src->w) ||
+		     ((srcrect->y+srcrect->h) > src->h) ) {
+			SDL_SetError("Invalid source blit rectangle");
+			return(-1);
+		}
+	} else {
+		full_src.x = 0;
+		full_src.y = 0;
+		full_src.w = src->w;
+		full_src.h = src->h;
+		srcrect = &full_src;
+	}
+	if ( dstrect ) {
+		if ( (dstrect->x < 0) || (dstrect->y < 0) ||
+		     ((dstrect->x+dstrect->w) > dst->w) ||
+		     ((dstrect->y+dstrect->h) > dst->h) ) {
+			SDL_SetError("Invalid destination blit rectangle");
+			return(-1);
+		}
+	} else {
+		full_dst.x = 0;
+		full_dst.y = 0;
+		full_dst.w = dst->w;
+		full_dst.h = dst->h;
+		dstrect = &full_dst;
+	}
+
+	/* Set up the data... */
+	pos = 0x10000;
+	inc = (srcrect->h << 16) / dstrect->h;
+	src_row = srcrect->y;
+	dst_row = dstrect->y;
+	dst_width = dstrect->w*bpp;
+
+#ifdef USE_ASM_STRETCH
+	/* Write the opcodes for this stretch */
+	if ( (bpp != 3) &&
+	     (generate_rowbytes(srcrect->w, dstrect->w, bpp) < 0) ) {
+		return(-1);
+	}
+#endif
+
+	/* Perform the stretch blit */
+	for ( dst_maxrow = dst_row+dstrect->h; dst_row<dst_maxrow; ++dst_row ) {
+		dstp = (Uint8 *)dst->pixels + (dst_row*dst->pitch)
+		                            + (dstrect->x*bpp);
+		while ( pos >= 0x10000L ) {
+			srcp = (Uint8 *)src->pixels + (src_row*src->pitch)
+			                            + (srcrect->x*bpp);
+			++src_row;
+			pos -= 0x10000L;
+		}
+#ifdef USE_ASM_STRETCH
+		switch (bpp) {
+		    case 3:
+			copy_row3(srcp, srcrect->w, dstp, dstrect->w);
+			break;
+		    default:
+#ifdef __GNUC__
+			__asm__ __volatile__ ("
+				call _copy_row
+			"
+			: "=&D" (u1), "=&S" (u2)
+			: "0" (dstp), "1" (srcp)
+			: "memory" );
+#else
+#ifdef WIN32
+		{ void *code = &copy_row;
+			__asm {
+				push edi
+				push esi
+	
+				mov edi, dstp
+				mov esi, srcp
+				call dword ptr code
+
+				pop esi
+				pop edi
+			}
+		}
+#else
+#error Need inline assembly for this compiler
+#endif
+#endif /* __GNUC__ */
+			break;
+		}
+#else
+		switch (bpp) {
+		    case 1:
+			copy_row1(srcp, srcrect->w, dstp, dstrect->w);
+			break;
+		    case 2:
+			copy_row2((Uint16 *)srcp, srcrect->w,
+			          (Uint16 *)dstp, dstrect->w);
+			break;
+		    case 3:
+			copy_row3(srcp, srcrect->w, dstp, dstrect->w);
+			break;
+		    case 4:
+			copy_row4((Uint32 *)srcp, srcrect->w,
+			          (Uint32 *)dstp, dstrect->w);
+			break;
+		}
+#endif
+		pos += inc;
+	}
+	return(0);
+}
+