From 8b8c51573bc568d70404a7d898ed07a8d2877bd8 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Wed, 29 Oct 2025 16:11:25 +0000
Subject: [PATCH] Disabled incorrect 16-bit Altivec blitters
---
src/video/SDL_blit_N.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/src/video/SDL_blit_N.c b/src/video/SDL_blit_N.c
index bdf1681616c23..63468cd3a07b4 100644
--- a/src/video/SDL_blit_N.c
+++ b/src/video/SDL_blit_N.c
@@ -292,6 +292,7 @@ static void Blit_XRGB8888_RGB565Altivec(SDL_BlitInfo *info)
}
}
+#ifdef BROKEN_ALTIVEC_BLITTERS // This doesn't properly expand to the lower destination bits
static void Blit_RGB565_32Altivec(SDL_BlitInfo *info)
{
int height = info->dst_h;
@@ -370,9 +371,7 @@ static void Blit_RGB565_32Altivec(SDL_BlitInfo *info)
while (condition) { \
unsigned sR, sG, sB; \
unsigned short Pixel = *((unsigned short *)src); \
- sR = (Pixel >> 8) & 0xf8; \
- sG = (Pixel >> 3) & 0xfc; \
- sB = (Pixel << 3) & 0xf8; \
+ RGB_FROM_RGB565(Pixel, sR, sG, sB); \
ASSEMBLE_RGBA(dst, 4, dstfmt, sR, sG, sB, alpha); \
src += 2; \
dst += 4; \
@@ -508,9 +507,7 @@ static void Blit_RGB555_32Altivec(SDL_BlitInfo *info)
while (condition) { \
unsigned sR, sG, sB; \
unsigned short Pixel = *((unsigned short *)src); \
- sR = (Pixel >> 7) & 0xf8; \
- sG = (Pixel >> 2) & 0xf8; \
- sB = (Pixel << 3) & 0xf8; \
+ RGB_FROM_RGB555(Pixel, sR, sG, sB); \
ASSEMBLE_RGBA(dst, 4, dstfmt, sR, sG, sB, alpha); \
src += 2; \
dst += 4; \
@@ -567,6 +564,7 @@ static void Blit_RGB555_32Altivec(SDL_BlitInfo *info)
dst += dstskip;
}
}
+#endif // BROKEN_ALTIVEC_BLITTERS
static void BlitNtoNKey(SDL_BlitInfo *info);
static void BlitNtoNKeyCopyAlpha(SDL_BlitInfo *info);
@@ -2969,11 +2967,13 @@ static const struct blit_table normal_blit_1[] = {
static const struct blit_table normal_blit_2[] = {
#ifdef SDL_ALTIVEC_BLITTERS
+#ifdef BROKEN_ALTIVEC_BLITTERS
// has-altivec
{ 0x0000F800, 0x000007E0, 0x0000001F, 4, 0x00000000, 0x00000000, 0x00000000,
BLIT_FEATURE_HAS_ALTIVEC, Blit_RGB565_32Altivec, NO_ALPHA | COPY_ALPHA | SET_ALPHA },
{ 0x00007C00, 0x000003E0, 0x0000001F, 4, 0x00000000, 0x00000000, 0x00000000,
BLIT_FEATURE_HAS_ALTIVEC, Blit_RGB555_32Altivec, NO_ALPHA | COPY_ALPHA | SET_ALPHA },
+#endif // BROKEN_ALTIVEC_BLITTERS
#endif
#ifdef SDL_SSE4_1_INTRINSICS
{ 0x0000F800, 0x000007E0, 0x0000001F, 4, 0x00FF0000, 0x0000FF00, 0x000000FF,