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Avoid left-shifting negative values in a number of places

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This is undefined behavior, according to specification.

BUG=chromium:661133

Review-Url: https://codereview.webrtc.org/2500953003
Cr-Commit-Position: refs/heads/master@{#15078}
This commit is contained in:
henrik.lundin 2016-11-15 01:45:53 -08:00 committed by Commit bot
parent fd5a20fd68
commit 79dfdadbc8
3 changed files with 20 additions and 20 deletions
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34
webrtc/common_audio/signal_processing/levinson_durbin.c
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@ -43,10 +43,10 @@ int16_t WebRtcSpl_LevinsonDurbin(const int32_t* R, int16_t* A, int16_t* K,
for (i = 0; i <= order; ++i)
{
temp1W32 = WEBRTC_SPL_LSHIFT_W32(R[i], norm);
temp1W32 = R[i] * (1 << norm);
// Put R in hi and low format
R_hi[i] = (int16_t)(temp1W32 >> 16);
R_low[i] = (int16_t)((temp1W32 - ((int32_t)R_hi[i] << 16)) >> 1);
R_low[i] = (int16_t)((temp1W32 - ((int32_t)R_hi[i] * 65536)) >> 1);
}
// K = A[1] = -R[1] / R[0]
@ -63,7 +63,7 @@ int16_t WebRtcSpl_LevinsonDurbin(const int32_t* R, int16_t* A, int16_t* K,
// Put K in hi and low format
K_hi = (int16_t)(temp1W32 >> 16);
K_low = (int16_t)((temp1W32 - ((int32_t)K_hi << 16)) >> 1);
K_low = (int16_t)((temp1W32 - ((int32_t)K_hi * 65536)) >> 1);
// Store first reflection coefficient
K[0] = K_hi;
@ -72,7 +72,7 @@ int16_t WebRtcSpl_LevinsonDurbin(const int32_t* R, int16_t* A, int16_t* K,
// Put A[1] in hi and low format
A_hi[1] = (int16_t)(temp1W32 >> 16);
A_low[1] = (int16_t)((temp1W32 - ((int32_t)A_hi[1] << 16)) >> 1);
A_low[1] = (int16_t)((temp1W32 - ((int32_t)A_hi[1] * 65536)) >> 1);
// Alpha = R[0] * (1-K^2)
@ -112,14 +112,14 @@ int16_t WebRtcSpl_LevinsonDurbin(const int32_t* R, int16_t* A, int16_t* K,
for (j = 1; j < i; j++)
{
// temp1W32 is in Q31
temp1W32 += (R_hi[j] * A_hi[i - j] << 1) +
temp1W32 += (R_hi[j] * A_hi[i - j] * 2) +
(((R_hi[j] * A_low[i - j] >> 15) +
(R_low[j] * A_hi[i - j] >> 15)) << 1);
(R_low[j] * A_hi[i - j] >> 15)) * 2);
}
temp1W32 = WEBRTC_SPL_LSHIFT_W32(temp1W32, 4);
temp1W32 += (WEBRTC_SPL_LSHIFT_W32((int32_t)R_hi[i], 16)
+ WEBRTC_SPL_LSHIFT_W32((int32_t)R_low[i], 1));
temp1W32 = temp1W32 * 16;
temp1W32 += ((int32_t)R_hi[i] * 65536)
+ WEBRTC_SPL_LSHIFT_W32((int32_t)R_low[i], 1);
// K = -temp1W32 / Alpha
temp2W32 = WEBRTC_SPL_ABS_W32(temp1W32); // abs(temp1W32)
@ -135,7 +135,7 @@ int16_t WebRtcSpl_LevinsonDurbin(const int32_t* R, int16_t* A, int16_t* K,
norm = WebRtcSpl_NormW32(temp3W32);
if ((Alpha_exp <= norm) || (temp3W32 == 0))
{
temp3W32 = WEBRTC_SPL_LSHIFT_W32(temp3W32, Alpha_exp);
temp3W32 = temp3W32 * (1 << Alpha_exp);
} else
{
if (temp3W32 > 0)
@ -149,7 +149,7 @@ int16_t WebRtcSpl_LevinsonDurbin(const int32_t* R, int16_t* A, int16_t* K,
// Put K on hi and low format
K_hi = (int16_t)(temp3W32 >> 16);
K_low = (int16_t)((temp3W32 - ((int32_t)K_hi << 16)) >> 1);
K_low = (int16_t)((temp3W32 - ((int32_t)K_hi * 65536)) >> 1);
// Store Reflection coefficient in Q15
K[i - 1] = K_hi;
@ -171,17 +171,17 @@ int16_t WebRtcSpl_LevinsonDurbin(const int32_t* R, int16_t* A, int16_t* K,
for (j = 1; j < i; j++)
{
// temp1W32 = A[j] in Q27
temp1W32 = WEBRTC_SPL_LSHIFT_W32((int32_t)A_hi[j],16)
temp1W32 = (int32_t)A_hi[j] * 65536
+ WEBRTC_SPL_LSHIFT_W32((int32_t)A_low[j],1);
// temp1W32 += K*A[i-j] in Q27
temp1W32 += (K_hi * A_hi[i - j] + (K_hi * A_low[i - j] >> 15) +
(K_low * A_hi[i - j] >> 15)) << 1;
(K_low * A_hi[i - j] >> 15)) * 2;
// Put Anew in hi and low format
A_upd_hi[j] = (int16_t)(temp1W32 >> 16);
A_upd_low[j] = (int16_t)(
(temp1W32 - ((int32_t)A_upd_hi[j] << 16)) >> 1);
(temp1W32 - ((int32_t)A_upd_hi[j] * 65536)) >> 1);
}
// temp3W32 = K in Q27 (Convert from Q31 to Q27)
@ -190,7 +190,7 @@ int16_t WebRtcSpl_LevinsonDurbin(const int32_t* R, int16_t* A, int16_t* K,
// Store Anew in hi and low format
A_upd_hi[i] = (int16_t)(temp3W32 >> 16);
A_upd_low[i] = (int16_t)(
(temp3W32 - ((int32_t)A_upd_hi[i] << 16)) >> 1);
(temp3W32 - ((int32_t)A_upd_hi[i] * 65536)) >> 1);
// Alpha = Alpha * (1-K^2)
@ -237,10 +237,10 @@ int16_t WebRtcSpl_LevinsonDurbin(const int32_t* R, int16_t* A, int16_t* K,
for (i = 1; i <= order; i++)
{
// temp1W32 in Q27
temp1W32 = WEBRTC_SPL_LSHIFT_W32((int32_t)A_hi[i], 16)
temp1W32 = (int32_t)A_hi[i] * 65536
+ WEBRTC_SPL_LSHIFT_W32((int32_t)A_low[i], 1);
// Round and store upper word
A[i] = (int16_t)(((temp1W32 << 1) + 32768) >> 16);
A[i] = (int16_t)(((temp1W32 * 2) + 32768) >> 16);
}
return 1; // Stable filters
}

2
webrtc/common_audio/signal_processing/vector_scaling_operations.c
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@ -37,7 +37,7 @@ void WebRtcSpl_VectorBitShiftW16(int16_t *res, size_t length,
{
for (i = length; i > 0; i--)
{
(*res++) = ((*in++) << (-right_shifts));
(*res++) = ((*in++) * (1 << (-right_shifts)));
}
}
}

4
webrtc/modules/audio_coding/neteq/expand.cc
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@ -712,7 +712,7 @@ void Expand::AnalyzeSignal(int16_t* random_vector) {
x2 = (x1 * x1) >> 14; // Shift 14 to keep result in Q14.
x3 = (x1 * x2) >> 14;
static const int kCoefficients[4] = { -5179, 19931, -16422, 5776 };
int32_t temp_sum = kCoefficients[0] << 14;
int32_t temp_sum = kCoefficients[0] * 16384;
temp_sum += kCoefficients[1] * x1;
temp_sum += kCoefficients[2] * x2;
temp_sum += kCoefficients[3] * x3;
@ -751,7 +751,7 @@ void Expand::AnalyzeSignal(int16_t* random_vector) {
// Calculate (1 - slope) / distortion_lag.
// Shift |slope| by 7 to Q20 before the division. The result is in Q20.
parameters.mute_slope = WebRtcSpl_DivW32W16(
(8192 - slope) << 7, static_cast<int16_t>(distortion_lag));
(8192 - slope) * 128, static_cast<int16_t>(distortion_lag));
if (parameters.voice_mix_factor <= 13107) {
// Make sure the mute factor decreases from 1.0 to 0.9 in no more than
// 6.25 ms.