Fixed bug 3816 - asm code in video/SDL_stretch.c
Sylvain
I propose this new version for SDL_stretch.c that drops mprotect and asm
Code is similar to the StretchLinear, but the steps computation are kept similar to the nearest.
so that:
- it's pixel perfect with nearest
- as fast as asm I think
- no asm, nor mprotect
- benefit for all archicture
diff --git a/src/video/SDL_stretch.c b/src/video/SDL_stretch.c
index 9e29e6e..9c062ae 100644
--- a/src/video/SDL_stretch.c
+++ b/src/video/SDL_stretch.c
@@ -20,214 +20,14 @@
*/
#include "../SDL_internal.h"
-/* This a stretch blit implementation based on ideas given to me by
- Tomasz Cejner - thanks! :)
-
- April 27, 2000 - Sam Lantinga
-*/
-
#include "SDL_video.h"
#include "SDL_blit.h"
#include "SDL_render.h"
-/* This isn't ready for general consumption yet - it should be folded
- into the general blitting mechanism.
-*/
-
-#if ((defined(_MSC_VER) && defined(_M_IX86)) || \
- (defined(__GNUC__) && defined(__i386__))) && SDL_ASSEMBLY_ROUTINES
-#define USE_ASM_STRETCH
-#endif
-
-/* There's a bug with gcc 4.4.1 and -O2 where srcp doesn't get the correct
- * value after the first scanline. */
-/* This bug seems fixed, at least with gcc >= 4.6 */
-#if defined(USE_ASM_STRETCH) && \
- defined(__GNUC__) && (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 6))
-#undef USE_ASM_STRETCH
-#endif
-
-/* And it doesn't work if mprotect isn't available */
-#if defined(USE_ASM_STRETCH) && \
- !defined(HAVE_MPROTECT) && !defined(__WIN32__)
-#undef USE_ASM_STRETCH
-#endif
-
-#ifdef USE_ASM_STRETCH
-
-#ifdef __WIN32__
-#define WIN32_LEAN_AND_MEAN
-#include <windows.h>
-#elif defined(HAVE_MPROTECT)
-#include <sys/types.h>
-#include <sys/mman.h>
-#endif
-#ifdef __GNUC__
-#define PAGE_ALIGNED __attribute__((__aligned__(4096)))
-#elif defined(_MSC_VER)
-#define PAGE_ALIGNED __declspec(align(4096))
-#else
-#undef USE_ASM_STRETCH
-#endif
-#endif /**/
-
-#ifdef USE_ASM_STRETCH
-
-#define PREFIX16 0x66
-#define STORE_BYTE 0xAA
-#define STORE_WORD 0xAB
-#define LOAD_BYTE 0xAC
-#define LOAD_WORD 0xAD
-#define RETURN 0xC3
-
-static PAGE_ALIGNED 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;
- int status;
- } last;
-
- int i;
- int pos, inc;
- unsigned char *eip, *fence;
- unsigned char load, store;
-#ifdef __WIN32__
- DWORD oldprot;
-#endif
-
- /* See if we need to regenerate the copy buffer */
- if ((src_w == last.src_w) && (dst_w == last.dst_w) && (bpp == last.bpp)) {
- return (last.status);
- }
- last.bpp = bpp;
- last.src_w = src_w;
- last.dst_w = dst_w;
- last.status = -1;
-
- switch (bpp) {
- case 1:
- load = LOAD_BYTE;
- store = STORE_BYTE;
- break;
- case 2:
- case 4:
- load = LOAD_WORD;
- store = STORE_WORD;
- break;
- default:
- return SDL_SetError("ASM stretch of %d bytes isn't supported", bpp);
- }
- /* Make the code writeable */
-#ifdef __WIN32__
- if (!VirtualProtect(copy_row, sizeof(copy_row), PAGE_READWRITE, &oldprot)) {
- return SDL_SetError("Couldn't make copy buffer writeable");
- }
-#elif defined(HAVE_MPROTECT)
- if (mprotect(copy_row, sizeof(copy_row), PROT_READ | PROT_WRITE) < 0) {
- return SDL_SetError("Couldn't make copy buffer writeable");
- }
-#endif
- pos = 0x10000;
- inc = (src_w << 16) / dst_w;
- eip = copy_row;
- fence = copy_row + sizeof(copy_row)-2;
- for (i = 0; i < dst_w; ++i) {
- while (pos >= 0x10000L) {
- if (eip == fence) {
- return -1;
- }
- if (bpp == 2) {
- *eip++ = PREFIX16;
- }
- *eip++ = load;
- pos -= 0x10000L;
- }
- if (eip == fence) {
- return -1;
- }
- if (bpp == 2) {
- *eip++ = PREFIX16;
- }
- *eip++ = store;
- pos += inc;
- }
- *eip++ = RETURN;
-
- /* Make the code executable but not writeable */
-#ifdef __WIN32__
- if (!VirtualProtect(copy_row, sizeof(copy_row), PAGE_EXECUTE_READ, &oldprot)) {
- return SDL_SetError("Couldn't make copy buffer executable");
- }
-#elif defined(HAVE_MPROTECT)
- if (mprotect(copy_row, sizeof(copy_row), PROT_READ | PROT_EXEC) < 0) {
- return SDL_SetError("Couldn't make copy buffer executable");
- }
-#endif
- last.status = 0;
- return (0);
-}
-#endif /* USE_ASM_STRETCH */
-
-#define DEFINE_COPY_ROW(name, type) \
-static 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; \
- } \
-}
-/* *INDENT-OFF* */
-DEFINE_COPY_ROW(copy_row1, Uint8)
-DEFINE_COPY_ROW(copy_row2, Uint16)
-DEFINE_COPY_ROW(copy_row4, Uint32)
-/* *INDENT-ON* */
-
-/* The ASM code doesn't handle 24-bpp stretch blits */
-static void
-copy_row3(Uint8 * src, int src_w, Uint8 * dst, int dst_w)
-{
- int i;
- int pos, inc;
- Uint8 pixel[3] = { 0, 0, 0 };
-
- 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;
- }
-}
-
static int SDL_LowerSoftStretchNearest(SDL_Surface *src, const SDL_Rect *srcrect, SDL_Surface *dst, const SDL_Rect *dstrect);
static int SDL_LowerSoftStretchLinear(SDL_Surface *src, const SDL_Rect *srcrect, SDL_Surface *dst, const SDL_Rect *dstrect);
static int SDL_UpperSoftStretch(SDL_Surface * src, const SDL_Rect * srcrect, SDL_Surface * dst, const SDL_Rect * dstrect, SDL_ScaleMode scaleMode);
-/* 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, const SDL_Rect *srcrect,
SDL_Surface *dst, const SDL_Rect *dstrect)
@@ -331,96 +131,6 @@
return ret;
}
-
-int
-SDL_LowerSoftStretchNearest(SDL_Surface *src, const SDL_Rect *srcrect,
- SDL_Surface *dst, const SDL_Rect *dstrect)
-{
- int pos, inc;
- int dst_maxrow;
- int src_row, dst_row;
- Uint8 *srcp = NULL;
- Uint8 *dstp;
-#ifdef USE_ASM_STRETCH
- SDL_bool use_asm = SDL_TRUE;
-#ifdef __GNUC__
- int u1, u2;
-#endif
-#endif /* USE_ASM_STRETCH */
- const int bpp = dst->format->BytesPerPixel;
-
- /* Set up the data... */
- pos = 0x10000;
- inc = (srcrect->h << 16) / dstrect->h;
- src_row = srcrect->y;
- dst_row = dstrect->y;
-
-#ifdef USE_ASM_STRETCH
- /* Write the opcodes for this stretch */
- if ((bpp == 3) || (generate_rowbytes(srcrect->w, dstrect->w, bpp) < 0)) {
- use_asm = SDL_FALSE;
- }
-#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
- if (use_asm) {
-#ifdef __GNUC__
- __asm__ __volatile__("call *%4":"=&D"(u1), "=&S"(u2)
- :"0"(dstp), "1"(srcp), "r"(copy_row)
- :"memory");
-#elif defined(_MSC_VER) || defined(__WATCOMC__)
- /* *INDENT-OFF* */
- {
- void *code = copy_row;
- __asm {
- push edi
- push esi
- mov edi, dstp
- mov esi, srcp
- call dword ptr code
- pop esi
- pop edi
- }
- }
- /* *INDENT-ON* */
-#else
-#error Need inline assembly for this compiler
-#endif
- } else
-#endif
- 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;
- }
- pos += inc;
- }
-
- return 0;
-}
-
-
/* bilinear interpolation precision must be < 8
Because with SSE: add-multiply: _mm_madd_epi16 works with signed int
so pixels 0xb1...... are negatives and false the result
@@ -436,6 +146,20 @@
#define FP_ONE FIXED_POINT(1)
+#define NEAREST___START \
+ int i; \
+ int fp_sum_h, fp_step_h, left_pad_h, right_pad_h; \
+ int fp_sum_w, fp_step_w, left_pad_w, right_pad_w; \
+ int fp_sum_w_init, left_pad_w_init, right_pad_w_init, dst_gap, middle_init; \
+ get_scaler_datas_nearest(src_h, dst_h, &fp_sum_h, &fp_step_h, &left_pad_h, &right_pad_h); \
+ get_scaler_datas_nearest(src_w, dst_w, &fp_sum_w, &fp_step_w, &left_pad_w, &right_pad_w); \
+ fp_sum_w_init = fp_sum_w + left_pad_w * fp_step_w; \
+ left_pad_w_init = left_pad_w; \
+ right_pad_w_init = right_pad_w; \
+ dst_gap = dst_pitch - bpp * dst_w; \
+ middle_init = dst_w - left_pad_w - right_pad_w; \
+
+
#define BILINEAR___START \
int i; \
int fp_sum_h, fp_step_h, left_pad_h, right_pad_h; \
@@ -1132,4 +856,126 @@
return ret;
}
+static SDL_INLINE void
+get_scaler_datas_nearest(int src_nb, int dst_nb, int *fp_start, int *fp_step, int *left_pad, int *right_pad)
+{
+ *fp_start = 0;
+ *fp_step = (src_nb << 16) / dst_nb;
+ *left_pad = 0;
+ *right_pad = 0;
+}
+
+static int
+scale_mat_nearest_1(const Uint32 *src, int src_w, int src_h, int src_pitch,
+ Uint32 *dst, int dst_w, int dst_h, int dst_pitch)
+{
+ const int bpp = 1;
+ NEAREST___START
+ for (i = 0; i < dst_h; i++) {
+ BILINEAR___HEIGHT
+ while (middle--) {
+ const Uint32 *s_00_01;
+ int index_w = bpp * SRC_INDEX(fp_sum_w);
+ fp_sum_w += fp_step_w;
+ s_00_01 = (const Uint32 *)((const Uint8 *)src_h0 + index_w);
+ *(Uint8*)dst = *(Uint8*)s_00_01;
+ dst = (Uint32 *)((Uint8*)dst + bpp);
+ }
+ dst = (Uint32 *)((Uint8 *)dst + dst_gap);
+ }
+ return 0;
+}
+
+static int
+scale_mat_nearest_2(const Uint32 *src, int src_w, int src_h, int src_pitch,
+ Uint32 *dst, int dst_w, int dst_h, int dst_pitch)
+{
+ const int bpp = 2;
+ NEAREST___START
+ for (i = 0; i < dst_h; i++) {
+ BILINEAR___HEIGHT
+ while (middle--) {
+ const Uint32 *s_00_01;
+ int index_w = bpp * SRC_INDEX(fp_sum_w);
+ fp_sum_w += fp_step_w;
+ s_00_01 = (const Uint32 *)((const Uint8 *)src_h0 + index_w);
+ *(Uint16*)dst = *(Uint16*)s_00_01;
+ dst = (Uint32 *)((Uint8*)dst + bpp);
+ }
+ dst = (Uint32 *)((Uint8 *)dst + dst_gap);
+ }
+ return 0;
+}
+
+static int
+scale_mat_nearest_3(const Uint32 *src, int src_w, int src_h, int src_pitch,
+ Uint32 *dst, int dst_w, int dst_h, int dst_pitch)
+{
+ const int bpp = 3;
+ NEAREST___START
+ for (i = 0; i < dst_h; i++) {
+ BILINEAR___HEIGHT
+ while (middle--) {
+ const Uint32 *s_00_01;
+ int index_w = bpp * SRC_INDEX(fp_sum_w);
+ fp_sum_w += fp_step_w;
+ s_00_01 = (const Uint32 *)((const Uint8 *)src_h0 + index_w);
+ ((Uint8*)dst)[0] = ((Uint8*)s_00_01)[0];
+ ((Uint8*)dst)[1] = ((Uint8*)s_00_01)[1];
+ ((Uint8*)dst)[2] = ((Uint8*)s_00_01)[2];
+ dst = (Uint32 *)((Uint8*)dst + bpp);
+ }
+ dst = (Uint32 *)((Uint8 *)dst + dst_gap);
+ }
+ return 0;
+}
+
+static int
+scale_mat_nearest_4(const Uint32 *src, int src_w, int src_h, int src_pitch,
+ Uint32 *dst, int dst_w, int dst_h, int dst_pitch)
+{
+ int bpp = 4;
+ NEAREST___START
+ for (i = 0; i < dst_h; i++) {
+ BILINEAR___HEIGHT
+ while (middle--) {
+ const Uint32 *s_00_01;
+ int index_w = bpp * SRC_INDEX(fp_sum_w);
+ fp_sum_w += fp_step_w;
+ s_00_01 = (const Uint32 *)((const Uint8 *)src_h0 + index_w);
+ *dst = *s_00_01;
+ dst = (Uint32 *)((Uint8*)dst + bpp);
+ }
+ dst = (Uint32 *)((Uint8 *)dst + dst_gap);
+ }
+ return 0;
+}
+
+int
+SDL_LowerSoftStretchNearest(SDL_Surface *s, const SDL_Rect *srcrect,
+ SDL_Surface *d, const SDL_Rect *dstrect)
+{
+ int src_w = srcrect->w;
+ int src_h = srcrect->h;
+ int dst_w = dstrect->w;
+ int dst_h = dstrect->h;
+ int src_pitch = s->pitch;
+ int dst_pitch = d->pitch;
+
+ const int bpp = d->format->BytesPerPixel;
+
+ Uint32 *src = (Uint32 *) ((Uint8 *)s->pixels + srcrect->x * bpp + srcrect->y * src_pitch);
+ Uint32 *dst = (Uint32 *) ((Uint8 *)d->pixels + dstrect->x * bpp + dstrect->y * dst_pitch);
+
+ if (bpp == 4) {
+ return scale_mat_nearest_4(src, src_w, src_h, src_pitch, dst, dst_w, dst_h, dst_pitch);
+ } else if (bpp == 3) {
+ return scale_mat_nearest_3(src, src_w, src_h, src_pitch, dst, dst_w, dst_h, dst_pitch);
+ } else if (bpp == 2) {
+ return scale_mat_nearest_2(src, src_w, src_h, src_pitch, dst, dst_w, dst_h, dst_pitch);
+ } else {
+ return scale_mat_nearest_1(src, src_w, src_h, src_pitch, dst, dst_w, dst_h, dst_pitch);
+ }
+}
+
/* vi: set ts=4 sw=4 expandtab: */
