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Code Issues Releases Activity

x86: dsputil: kill VLA in gmc_mmx()

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Instead of using an evil VLA, fall back to C version when edge
emulation is needed.  MPEG4 GMC is a rarely used fringe feature
so the speed loss is an acceptable cost for safer code.

Signed-off-by: Mans Rullgard <mans@mansr.com>
This commit is contained in:
Mans Rullgard 2012-10-03 22:53:00 +01:00
parent f1c6a740fc
commit bcf07a15a0
1 changed files with 7 additions and 51 deletions
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58
libavcodec/x86/dsputil_mmx.c
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@ -1909,15 +1909,10 @@ static av_noinline void emulated_edge_mc_sse(uint8_t *buf, const uint8_t *src,
#if HAVE_INLINE_ASM
typedef void emulated_edge_mc_func(uint8_t *dst, const uint8_t *src,
int linesize, int block_w, int block_h,
int src_x, int src_y, int w, int h);
static av_always_inline void gmc(uint8_t *dst, uint8_t *src,
int stride, int h, int ox, int oy,
int dxx, int dxy, int dyx, int dyy,
int shift, int r, int width, int height,
emulated_edge_mc_func *emu_edge_fn)
static void gmc_mmx(uint8_t *dst, uint8_t *src,
int stride, int h, int ox, int oy,
int dxx, int dxy, int dyx, int dyy,
int shift, int r, int width, int height)
{
const int w = 8;
const int ix = ox >> (16 + shift);
@ -1932,7 +1927,6 @@ static av_always_inline void gmc(uint8_t *dst, uint8_t *src,
const uint16_t dxy4[4] = { dxys, dxys, dxys, dxys };
const uint16_t dyy4[4] = { dyys, dyys, dyys, dyys };
const uint64_t shift2 = 2 * shift;
uint8_t edge_buf[(h + 1) * stride];
int x, y;
const int dxw = (dxx - (1 << (16 + shift))) * (w - 1);
@ -1943,7 +1937,9 @@ static av_always_inline void gmc(uint8_t *dst, uint8_t *src,
((ox ^ (ox + dxw)) | (ox ^ (ox + dxh)) | (ox ^ (ox + dxw + dxh)) |
(oy ^ (oy + dyw)) | (oy ^ (oy + dyh)) | (oy ^ (oy + dyw + dyh))) >> (16 + shift)
// uses more than 16 bits of subpel mv (only at huge resolution)
|| (dxx | dxy | dyx | dyy) & 15) {
|| (dxx | dxy | dyx | dyy) & 15 ||
(unsigned)ix >= width - w ||
(unsigned)iy >= height - h) {
// FIXME could still use mmx for some of the rows
ff_gmc_c(dst, src, stride, h, ox, oy, dxx, dxy, dyx, dyy,
shift, r, width, height);
@ -1951,11 +1947,6 @@ static av_always_inline void gmc(uint8_t *dst, uint8_t *src,
}
src += ix + iy * stride;
if ((unsigned)ix >= width - w ||
(unsigned)iy >= height - h) {
emu_edge_fn(edge_buf, src, stride, w + 1, h + 1, ix, iy, width, height);
src = edge_buf;
}
__asm__ volatile (
"movd %0, %%mm6 \n\t"
@ -2034,36 +2025,6 @@ static av_always_inline void gmc(uint8_t *dst, uint8_t *src,
}
}
#if HAVE_YASM
#if ARCH_X86_32
static void gmc_mmx(uint8_t *dst, uint8_t *src,
int stride, int h, int ox, int oy,
int dxx, int dxy, int dyx, int dyy,
int shift, int r, int width, int height)
{
gmc(dst, src, stride, h, ox, oy, dxx, dxy, dyx, dyy, shift, r,
width, height, &emulated_edge_mc_mmx);
}
#endif
static void gmc_sse(uint8_t *dst, uint8_t *src,
int stride, int h, int ox, int oy,
int dxx, int dxy, int dyx, int dyy,
int shift, int r, int width, int height)
{
gmc(dst, src, stride, h, ox, oy, dxx, dxy, dyx, dyy, shift, r,
width, height, &emulated_edge_mc_sse);
}
#else
static void gmc_mmx(uint8_t *dst, uint8_t *src,
int stride, int h, int ox, int oy,
int dxx, int dxy, int dyx, int dyy,
int shift, int r, int width, int height)
{
gmc(dst, src, stride, h, ox, oy, dxx, dxy, dyx, dyy, shift, r,
width, height, &ff_emulated_edge_mc_8);
}
#endif
#define PREFETCH(name, op) \
static void name(void *mem, int stride, int h) \
{ \
@ -2469,9 +2430,7 @@ static void dsputil_init_mmx(DSPContext *c, AVCodecContext *avctx, int mm_flags)
}
}
#if ARCH_X86_32 || !HAVE_YASM
c->gmc = gmc_mmx;
#endif
c->add_bytes = add_bytes_mmx;
@ -2729,9 +2688,6 @@ static void dsputil_init_sse(DSPContext *c, AVCodecContext *avctx, int mm_flags)
if (!high_bit_depth)
c->emulated_edge_mc = emulated_edge_mc_sse;
#if HAVE_INLINE_ASM
c->gmc = gmc_sse;
#endif
#endif /* HAVE_YASM */
}