On 5/27/2024 4:10 PM, James Almer wrote:
On 5/27/2024 1:01 PM, Rémi Denis-Courmont wrote:
---
Changes since v2:
- Scale the error factor to length since this computes sums.
- Check the last element from results.
- Use fixed vector size for benchmarks.
---
tests/checkasm/lpc.c | 51 +++++++++++++++++++++++++++++++++++++++++---
1 file changed, 48 insertions(+), 3 deletions(-)
checkasm: using random seed 883526087
checkasm: bench runs 1024 (1 << 10)
SSE2:
- lpc.apply_welch_window_even [OK]
- lpc.apply_welch_window_odd [OK]
8: 666.011902576448 - 665.600444506565 = 0.411458069884
autocorr_8_sse2 (lpc.c:88)
- lpc.compute_autocorr [FAILED]
The following fixes it:
diff --git a/libavcodec/x86/lpc_init.c b/libavcodec/x86/lpc_init.c
index f2fca53799..9f41639feb 100644
--- a/libavcodec/x86/lpc_init.c
+++ b/libavcodec/x86/lpc_init.c
@@ -99,6 +99,15 @@ static void lpc_compute_autocorr_sse2(const double *data,
ptrdiff_t len, int lag
);
}
}
+
+ if(j==lag){
+ double sum = 1.0;
+ for(int i=j-1; i<len; i+=2){
+ sum += data[i ] * data[i-j ]
+ + data[i+1] * data[i-j+1];
+ }
+ autoc[j] = sum;
+ }
}
#endif /* HAVE_SSE2_INLINE */
So the SSE2 version is effectively broken, and ideally should be ported
to nasm as it's fixed.
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