From e05aea9785f709f5aebb696ee5b4460681676e10 Mon Sep 17 00:00:00 2001
From: Jean-Marc Valin <jmvalin@amazon.com>
Date: Fri, 22 Jul 2022 02:29:05 -0400
Subject: Using saturating round to fix some wrap-arounds

Reviewed by Mark Harris
---
 celt/celt_decoder.c |  8 ++++----
 celt/celt_lpc.c     | 10 +++++-----
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/celt/celt_decoder.c b/celt/celt_decoder.c
index 35a2073a..883dae15 100644
--- a/celt/celt_decoder.c
+++ b/celt/celt_decoder.c
@@ -629,7 +629,7 @@ static void celt_decode_lost(CELTDecoder * OPUS_RESTRICT st, int N, int LM)
 
          buf = decode_mem[c];
          for (i=0;i<MAX_PERIOD+LPC_ORDER;i++)
-            exc[i-LPC_ORDER] = ROUND16(buf[DECODE_BUFFER_SIZE-MAX_PERIOD-LPC_ORDER+i], SIG_SHIFT);
+            exc[i-LPC_ORDER] = SROUND16(buf[DECODE_BUFFER_SIZE-MAX_PERIOD-LPC_ORDER+i], SIG_SHIFT);
 
          if (loss_duration == 0)
          {
@@ -731,7 +731,7 @@ static void celt_decode_lost(CELTDecoder * OPUS_RESTRICT st, int N, int LM)
                         exc[extrapolation_offset+j])), SIG_SHIFT);
             /* Compute the energy of the previously decoded signal whose
                excitation we're copying. */
-            tmp = ROUND16(
+            tmp = SROUND16(
                   buf[DECODE_BUFFER_SIZE-MAX_PERIOD-N+extrapolation_offset+j],
                   SIG_SHIFT);
             S1 += SHR32(MULT16_16(tmp, tmp), 10);
@@ -741,7 +741,7 @@ static void celt_decode_lost(CELTDecoder * OPUS_RESTRICT st, int N, int LM)
             /* Copy the last decoded samples (prior to the overlap region) to
                synthesis filter memory so we can have a continuous signal. */
             for (i=0;i<LPC_ORDER;i++)
-               lpc_mem[i] = ROUND16(buf[DECODE_BUFFER_SIZE-N-1-i], SIG_SHIFT);
+               lpc_mem[i] = SROUND16(buf[DECODE_BUFFER_SIZE-N-1-i], SIG_SHIFT);
             /* Apply the synthesis filter to convert the excitation back into
                the signal domain. */
             celt_iir(buf+DECODE_BUFFER_SIZE-N, lpc+c*LPC_ORDER,
@@ -760,7 +760,7 @@ static void celt_decode_lost(CELTDecoder * OPUS_RESTRICT st, int N, int LM)
             opus_val32 S2=0;
             for (i=0;i<extrapolation_len;i++)
             {
-               opus_val16 tmp = ROUND16(buf[DECODE_BUFFER_SIZE-N+i], SIG_SHIFT);
+               opus_val16 tmp = SROUND16(buf[DECODE_BUFFER_SIZE-N+i], SIG_SHIFT);
                S2 += SHR32(MULT16_16(tmp, tmp), 10);
             }
             /* This checks for an "explosion" in the synthesis. */
diff --git a/celt/celt_lpc.c b/celt/celt_lpc.c
index 242e6df5..f91721bc 100644
--- a/celt/celt_lpc.c
+++ b/celt/celt_lpc.c
@@ -159,17 +159,17 @@ void celt_fir_c(
       sum[2] = SHL32(EXTEND32(x[i+2]), SIG_SHIFT);
       sum[3] = SHL32(EXTEND32(x[i+3]), SIG_SHIFT);
       xcorr_kernel(rnum, x+i-ord, sum, ord, arch);
-      y[i  ] = ROUND16(sum[0], SIG_SHIFT);
-      y[i+1] = ROUND16(sum[1], SIG_SHIFT);
-      y[i+2] = ROUND16(sum[2], SIG_SHIFT);
-      y[i+3] = ROUND16(sum[3], SIG_SHIFT);
+      y[i  ] = SROUND16(sum[0], SIG_SHIFT);
+      y[i+1] = SROUND16(sum[1], SIG_SHIFT);
+      y[i+2] = SROUND16(sum[2], SIG_SHIFT);
+      y[i+3] = SROUND16(sum[3], SIG_SHIFT);
    }
    for (;i<N;i++)
    {
       opus_val32 sum = SHL32(EXTEND32(x[i]), SIG_SHIFT);
       for (j=0;j<ord;j++)
          sum = MAC16_16(sum,rnum[j],x[i+j-ord]);
-      y[i] = ROUND16(sum, SIG_SHIFT);
+      y[i] = SROUND16(sum, SIG_SHIFT);
    }
    RESTORE_STACK;
 }
-- 
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