diff options
Diffstat (limited to 'libavcodec/simple_idct.c')
| -rw-r--r-- | libavcodec/simple_idct.c | 32 |
1 files changed, 25 insertions, 7 deletions
diff --git a/libavcodec/simple_idct.c b/libavcodec/simple_idct.c index 9ff10eea51..a9653b1877 100644 --- a/libavcodec/simple_idct.c +++ b/libavcodec/simple_idct.c @@ -104,6 +104,7 @@ static int inline idctRowCondZ (int16_t * row) } #ifdef ARCH_ALPHA +/* 0: all entries 0, 1: only first entry nonzero, 2: otherwise */ static int inline idctRowCondDC(int16_t *row) { int_fast32_t a0, a1, a2, a3, b0, b1, b2, b3; @@ -201,7 +202,7 @@ static int inline idctRowCondDC(int16_t *row) row[6] = (a1 - b1) >> ROW_SHIFT; row[7] = (a0 - b0) >> ROW_SHIFT; - return 1; + return 2; } #else /* not ARCH_ALPHA */ static int inline idctRowCondDC (int16_t * row) @@ -547,16 +548,33 @@ void simple_idct (short *block) idctSparse2Col(block + i); } #elif defined(ARCH_ALPHA) - int shortcut = 1; + int rowsZero = 1; /* all rows except row 0 zero */ + int rowsConstant = 1; /* all rows consist of a constant value */ for (i = 0; i < 8; i++) { - int anynonzero = idctRowCondDC(block + 8 * i); - if (i > 0 && anynonzero) - shortcut = 0; + int sparseness = idctRowCondDC(block + 8 * i); + + if (i > 0 && sparseness > 0) + rowsZero = 0; + if (sparseness == 2) + rowsConstant = 0; } - if (shortcut) { - idctCol2(block); + if (rowsZero) { + idctCol2(block); + } else if (rowsConstant) { + uint64_t *lblock = (uint64_t *) block; + + idctSparseCol(block); + for (i = 0; i < 8; i++) { + uint64_t v = (uint16_t) block[i * 8]; + + v += v << 16; + v += v << 32; + lblock[0] = v; + lblock[1] = v; + lblock += 2; + } } else { for (i = 0; i < 8; i++) idctSparseCol(block + i); |