From: Peter Meerwald <p.meerwald@xxxxxxxxxxxxxxxxxx>
implement lrintf semantic (round toward nearest, even tie breaking)
lrintf() rounds according to the current rounding mode which by default is
round-toward-nearest integer, toward-even for tie breaking)
for example, this means
12.3 -> 12
12.5 -> 12 (!)
12.7 -> 13
13.3 -> 13
13.5 -> 14 (!)
13.7 -> 14
previous code did different tie breaking (toward-zero), hence results were
different for .5 values
Signed-off-by: Peter Meerwald <p.meerwald at bct-electronic.com>
---
src/pulsecore/sconv_neon.c | 29 +++++++++++++----------------
1 file changed, 13 insertions(+), 16 deletions(-)
diff --git a/src/pulsecore/sconv_neon.c b/src/pulsecore/sconv_neon.c
index 81dd97e..cbca232 100644
--- a/src/pulsecore/sconv_neon.c
+++ b/src/pulsecore/sconv_neon.c
@@ -36,22 +36,19 @@ static void pa_sconv_s16le_from_f32ne_neon(unsigned n, const float *src, int16_t
"movs %[n], %[n], lsr #2 \n\t"
"beq 2f \n\t"
- "vdup.f32 q2, %[plusone] \n\t"
- "vneg.f32 q3, q2 \n\t"
- "vdup.f32 q4, %[scale] \n\t"
- "vdup.u32 q5, %[mask] \n\t"
- "vdup.f32 q6, %[half] \n\t"
+ "vdup.f32 q2, %[two23] \n\t"
+ "vdup.f32 q3, %[scale] \n\t"
+ "vdup.u32 q4, %[mask] \n\t"
"1: \n\t"
- "vld1.32 {q0}, [%[src]]! \n\t"
- "vmin.f32 q0, q0, q2 \n\t" /* clamp */
- "vmax.f32 q0, q0, q3 \n\t"
- "vmul.f32 q0, q0, q4 \n\t" /* scale */
- "vand.u32 q1, q0, q5 \n\t"
- "vorr.u32 q1, q1, q6 \n\t" /* round */
- "vadd.f32 q0, q0, q1 \n\t"
- "vcvt.s32.f32 q0, q0 \n\t" /* narrow */
- "vmovn.i32 d0, q0 \n\t"
+ "vld1.32 {q0}, [%[src]]! \n\t" /* load x */
+ "vmul.f32 q0, q0, q3 \n\t" /* scale */
+ "vand.u32 q1, q0, q4 \n\t" /* get sign bit */
+ "vorr.u32 q1, q1, q2 \n\t" /* put sign on 2^23 */
+ "vadd.f32 q0, q1, q0 \n\t" /* sgn(x)*2^23 + x ... */
+ "vsub.f32 q0, q0, q1 \n\t" /* ... - sgn(x)*2^23 */
+ "vcvt.s32.f32 q0, q0 \n\t" /* convert to int */
+ "vqmovn.s32 d0, q0 \n\t" /* saturate and narrow */
"subs %[n], %[n], #1 \n\t"
"vst1.16 {d0}, [%[dst]]! \n\t"
"bgt 1b \n\t"
@@ -59,8 +56,8 @@ static void pa_sconv_s16le_from_f32ne_neon(unsigned n, const float *src, int16_t
"2: \n\t"
: [dst] "+r" (dst), [src] "+r" (src), [n] "+r" (n) /* output operands (or input operands that get modified) */
- : [plusone] "r" (1.0f), [scale] "r" (32767.0f), [half] "r" (0.5f), [mask] "r" (0x80000000) /* input operands */
- : "memory", "cc", "q0", "q1", "q2", "q3", "q4", "q5", "q6" /* clobber list */
+ : [scale] "r" (32767.0f), [two23] "r" (8.3886080000e+06f), [mask] "r" (0x80000000) /* input operands */
+ : "memory", "cc", "q0", "q1", "q2", "q3", "q4" /* clobber list */
);
/* leftovers */
--
1.7.9.5
