Tell user how many bytes are needed

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%401105

src/video/gem/SDL_gemvideo.c

@@ -674,7 +674,7 @@ SDL_Surface *GEM_SetVideoMode(_THIS, SDL_Surface *current,
 	if (use_shadow1) {
 		GEM_buffer1 = Atari_SysMalloc(screensize, MX_PREFTTRAM);
 		if (GEM_buffer1==NULL) {
-			SDL_SetError("Unable to allocate shadow buffer");
+			SDL_SetError("Can not allocate %d KB for frame buffer", screensize>>10);
 			return NULL;
 		}
 		memset(GEM_buffer1, 0, screensize);
@@ -686,7 +686,7 @@ SDL_Surface *GEM_SetVideoMode(_THIS, SDL_Surface *current,
 	if (use_shadow2) {
 		GEM_buffer2 = Atari_SysMalloc(screensize, MX_PREFTTRAM);
 		if (GEM_buffer2==NULL) {
-			SDL_SetError("Unable to allocate shadow buffer");
+			SDL_SetError("Can not allocate %d KB for shadow buffer", screensize>>10);
 			return NULL;
 		}
 		memset(GEM_buffer2, 0, screensize);

src/video/xbios/SDL_xbios.c

@@ -552,7 +552,7 @@ static SDL_Surface *XBIOS_SetVideoMode(_THIS, SDL_Surface *current,
 		XBIOS_shadowscreen = Atari_SysMalloc(new_screen_size, MX_PREFTTRAM);
 
 		if (XBIOS_shadowscreen == NULL) {
-			SDL_SetError("XBIOS_SetVideoMode: Not enough memory for shadow surface");
+			SDL_SetError("Can not allocate %d KB for shadow buffer", new_screen_size>>10);
 			return (NULL);
 		}
 		memset(XBIOS_shadowscreen, 0, new_screen_size);
@@ -569,7 +569,7 @@ static SDL_Surface *XBIOS_SetVideoMode(_THIS, SDL_Surface *current,
 
 	if (XBIOS_screensmem[0]==NULL) {
 		XBIOS_FreeBuffers(this);
-		SDL_SetError("XBIOS_SetVideoMode: Not enough memory for video buffer");
+		SDL_SetError("Can not allocate %d KB for frame buffer", new_screen_size>>10);
 		return (NULL);
 	}
 	memset(XBIOS_screensmem[0], 0, new_screen_size);
@@ -590,7 +590,7 @@ static SDL_Surface *XBIOS_SetVideoMode(_THIS, SDL_Surface *current,
 
 		if (XBIOS_screensmem[1]==NULL) {
 			XBIOS_FreeBuffers(this);
-			SDL_SetError("XBIOS_SetVideoMode: Not enough memory for double buffer");
+			SDL_SetError("Can not allocate %d KB for double buffer", new_screen_size>>10);
 			return (NULL);
 		}
 		memset(XBIOS_screensmem[1], 0, new_screen_size);