From 74a05a7f53878c70d10326d60d75e39fd93d944c Mon Sep 17 00:00:00 2001
From: Max Kellermann <max@duempel.org>
Date: Wed, 19 Mar 2014 06:54:04 +0100
Subject: [PATCH] pcm/Neon: explicit rounding
Convert to 31 bit first, then right-shift with rounding to 16 bit.
---
src/pcm/Neon.hxx | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/src/pcm/Neon.hxx b/src/pcm/Neon.hxx
index ba31e55b8..7109778ab 100644
--- a/src/pcm/Neon.hxx
+++ b/src/pcm/Neon.hxx
@@ -76,11 +76,13 @@ struct NeonFloatTo16 {
/* convert to 32 bit integer */
int32x4x4_t ivalue;
neon_x4_b(vcvtq_n_s32_f32, ivalue, value,
- DstTraits::BITS - 1);
+ 30);
- /* convert to 16 bit integer with saturation */
+ /* convert to 16 bit integer with saturation
+ and rounding */
int16x4x4_t nvalue;
- neon_x4_u(vqmovn_s32, nvalue, ivalue);
+ neon_x4_b(vqrshrn_n_s32, nvalue, ivalue,
+ 30 - DstTraits::BITS + 1);
/* store result */
vst4_s16(dst, nvalue);