From fe8df88d8f97fb733bc7e63ca9d948746fea0bd7 Mon Sep 17 00:00:00 2001
From: Vladimir Malenovsky <vladimir.malenovsky@dolby.com>
Date: Mon, 22 Jun 2026 13:04:20 +0200
Subject: [PATCH] use double -prec sin() and cos() to fix 1-2 ULP precision
 issue

---
 lib_com/ivas_agc_com.c  |  4 ++++
 lib_com/ivas_fb_mixer.c | 12 ++++++++++++
 lib_com/options.h       |  3 ++-
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/lib_com/ivas_agc_com.c b/lib_com/ivas_agc_com.c
index 12b098869..cd4441b74 100644
--- a/lib_com/ivas_agc_com.c
+++ b/lib_com/ivas_agc_com.c
@@ -71,7 +71,11 @@ void ivas_agc_initWindowFunc(
 
     for ( i = 0; i < length; i++ )
     {
+#ifdef FIX_ISSUE_1603_SINF_COSF_PRECISION_XTENSA
+        pWinFunc[i] = 1.f + a * ( (float) cos( (double) ( EVS_PI * i / N ) ) - 1.f );
+#else
         pWinFunc[i] = 1.f + a * ( cosf( EVS_PI * i / N ) - 1.f );
+#endif
     }
 
     return;
diff --git a/lib_com/ivas_fb_mixer.c b/lib_com/ivas_fb_mixer.c
index 1e9fe1eb3..4dcf14993 100644
--- a/lib_com/ivas_fb_mixer.c
+++ b/lib_com/ivas_fb_mixer.c
@@ -1220,7 +1220,11 @@ static void ivas_get_hanning_win(
 
     for ( i = 0; i < len; i++ )
     {
+#ifdef FIX_ISSUE_1603_SINF_COSF_PRECISION_XTENSA
+        pH_win[i] = 0.5f * ( 1.0f - (float) cos( (double) ( PI2 * ( i + 1 ) ) / (double) ( ( 2 * len ) + 1 ) ) );
+#else
         pH_win[i] = 0.5f * ( 1.0f - cosf( ( PI2 * ( i + 1 ) ) / ( ( 2 * len ) + 1 ) ) );
+#endif
     }
 
     return;
@@ -1320,12 +1324,20 @@ static void ivas_get_ld_fb_resp(
         /* apply final window*/
         for ( s = 0; s < delay; s++ )
         {
+#ifdef FIX_ISSUE_1603_SINF_COSF_PRECISION_XTENSA
+            scratch1[s] = scratch1[s] * (float) sin( (double) ( EVS_PI * ( s + 1 ) ) / (double) ( 2 * delay ) );
+#else
             scratch1[s] = scratch1[s] * sinf( ( EVS_PI * ( s + 1 ) ) / ( 2 * delay ) );
+#endif
         }
 
         for ( s = 2 * delay; s < frame_len + 1; s++ )
         {
+#ifdef FIX_ISSUE_1603_SINF_COSF_PRECISION_XTENSA
+            scratch1[s] = scratch1[s] * (float) sin( (double) ( EVS_PI * ( frame_len - s ) ) / (double) ( 2 * ( frame_len + 1 - ( 2 * delay ) ) ) );
+#else
             scratch1[s] = scratch1[s] * sinf( ( EVS_PI * ( frame_len - s ) ) / ( 2 * ( frame_len + 1 - ( 2 * delay ) ) ) );
+#endif
         }
 
         for ( ; s < 2 * frame_len; s++ )
diff --git a/lib_com/options.h b/lib_com/options.h
index a33f3986f..422d0a8b4 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -170,7 +170,8 @@
 /* any switch which is non-be wrt. TS 26.258 V3.0 */
 
 #define FIX_1576_LCLD_CRASH_DIFFERENT_CODEC_ISAR_FRAME_SIZE  /* Dolby: float issue 1576: fix for crash in LCLD mode when codec frame size is less than isar frame size */
-#define FIX_FLOAT_1600_OMASA_WRONG_RENDER_PATH          /* Nokia: float issue 1600: fix initialization condition of stereo type detection for OMASA */
+#define FIX_FLOAT_1600_OMASA_WRONG_RENDER_PATH               /* Nokia: float issue 1600: fix initialization condition of stereo type detection for OMASA */
+#define FIX_ISSUE_1603_SINF_COSF_PRECISION_XTENSA            /* Dolby: use double-precision cos()/sin() in place of cosf()/sinf() in fb_mixer and agc_com to eliminate 1-2 ULP variance */
 
 /* ##################### End NON-BE switches ########################### */
 
-- 
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