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authorMax Kellermann <max@duempel.org>2014-03-16 08:57:04 +0100
committerMax Kellermann <max@duempel.org>2014-03-16 09:05:30 +0100
commit6f4775a8eeb30d0fde622f4e89979179af47d219 (patch)
tree4bf9185d16cecb79921e4e961c37e477cdb29977 /src/pcm
parentc7e2f558a0608eda343ab6f4d8801204497bebf5 (diff)
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pcm/Neon: apply bit shift during float->int conversion
Avoid multiplication. This is a speedup of 20%.
Diffstat (limited to 'src/pcm')
-rw-r--r--src/pcm/Neon.hxx9
1 files changed, 2 insertions, 7 deletions
diff --git a/src/pcm/Neon.hxx b/src/pcm/Neon.hxx
index a6f52db42..2d3a59d2b 100644
--- a/src/pcm/Neon.hxx
+++ b/src/pcm/Neon.hxx
@@ -68,21 +68,16 @@ struct NeonFloatTo16 {
static constexpr size_t BLOCK_SIZE = 16;
void Convert(int16_t *dst, const float *src, const size_t n) const {
- const float32x4_t factor =
- vdupq_n_f32(1 << (DstTraits::BITS - 1));
-
for (unsigned i = 0; i < n / BLOCK_SIZE;
++i, src += BLOCK_SIZE, dst += BLOCK_SIZE) {
/* load 16 float samples into 4 quad
registers */
float32x4x4_t value = vld4q_f32(src);
- /* apply factor */
- neon_x4_b(vmulq_f32, value, value, factor);
-
/* convert to 32 bit integer */
int32x4x4_t ivalue;
- neon_x4_u(vcvtq_s32_f32, ivalue, value);
+ neon_x4_b(vcvtq_n_s32_f32, ivalue, value,
+ DstTraits::BITS - 1);
/* convert to 16 bit integer with saturation */
int16x4x4_t nvalue;