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Diffstat (limited to 'libavcodec/x86/mpegvideo.c')
| -rw-r--r-- | libavcodec/x86/mpegvideo.c | 22 |
1 files changed, 0 insertions, 22 deletions
diff --git a/libavcodec/x86/mpegvideo.c b/libavcodec/x86/mpegvideo.c index f6db8c85d9..f8cabe5ddb 100644 --- a/libavcodec/x86/mpegvideo.c +++ b/libavcodec/x86/mpegvideo.c @@ -164,28 +164,6 @@ __asm__ volatile( ); } - -/* - We can suppose that result of two multiplications can't be greater than 0xFFFF - i.e. is 16-bit, so we use here only PMULLW instruction and can avoid - a complex multiplication. -===================================================== - Full formula for multiplication of 2 integer numbers - which are represent as high:low words: - input: value1 = high1:low1 - value2 = high2:low2 - output: value3 = value1*value2 - value3=high3:low3 (on overflow: modulus 2^32 wrap-around) - this mean that for 0x123456 * 0x123456 correct result is 0x766cb0ce4 - but this algorithm will compute only 0x66cb0ce4 - this limited by 16-bit size of operands - --------------------------------- - tlow1 = high1*low2 - tlow2 = high2*low1 - tlow1 = tlow1 + tlow2 - high3:low3 = low1*low2 - high3 += tlow1 -*/ static void dct_unquantize_mpeg1_intra_mmx(MpegEncContext *s, int16_t *block, int n, int qscale) { |