Optimize silk_NSQ_del_dec() for ARM NEON

The optimization is bit exact with C function.

This optimization speeds up SILK encoder on NEON as following.

Fixed-point:
Complexity 0-5:  0%
Complexity 6-7:  6%
Complexity 8-9: 10%
Complexity  10:  8%

Got similar results on floating-point.

Signed-off-by: Jean-Marc Valin <jmvalin@jmvalin.ca>

silk/SigProc_FIX.h

@@ -580,7 +580,9 @@ static OPUS_INLINE opus_int64 silk_max_64(opus_int64 a, opus_int64 b)
 /* Make sure to store the result as the seed for the next call (also in between     */
 /* frames), otherwise result won't be random at all. When only using some of the    */
 /* bits, take the most significant bits by right-shifting.                          */
-#define silk_RAND(seed)                     (silk_MLA_ovflw(907633515, (seed), 196314165))
+#define RAND_MULTIPLIER                     196314165
+#define RAND_INCREMENT                      907633515
+#define silk_RAND(seed)                     (silk_MLA_ovflw((RAND_INCREMENT), (seed), (RAND_MULTIPLIER)))
 
 /*  Add some multiplication functions that can be easily mapped to ARM. */
 

silk/arm/NSQ_del_dec_arm.h

+/***********************************************************************
+Copyright (c) 2017 Google Inc.
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+- Redistributions of source code must retain the above copyright notice,
+this list of conditions and the following disclaimer.
+- Redistributions in binary form must reproduce the above copyright
+notice, this list of conditions and the following disclaimer in the
+documentation and/or other materials provided with the distribution.
+- Neither the name of Internet Society, IETF or IETF Trust, nor the
+names of specific contributors, may be used to endorse or promote
+products derived from this software without specific prior written
+permission.
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+***********************************************************************/
+
+#ifndef SILK_NSQ_DEL_DEC_ARM_H
+#define SILK_NSQ_DEL_DEC_ARM_H
+
+#include "celt/arm/armcpu.h"
+
+#if defined(OPUS_ARM_MAY_HAVE_NEON_INTR)
+void silk_NSQ_del_dec_neon(
+    const silk_encoder_state *psEncC, silk_nsq_state *NSQ,
+    SideInfoIndices *psIndices, const opus_int16 x16[], opus_int8 pulses[],
+    const opus_int16 PredCoef_Q12[2 * MAX_LPC_ORDER],
+    const opus_int16 LTPCoef_Q14[LTP_ORDER * MAX_NB_SUBFR],
+    const opus_int16 AR_Q13[MAX_NB_SUBFR * MAX_SHAPE_LPC_ORDER],
+    const opus_int HarmShapeGain_Q14[MAX_NB_SUBFR],
+    const opus_int Tilt_Q14[MAX_NB_SUBFR],
+    const opus_int32 LF_shp_Q14[MAX_NB_SUBFR],
+    const opus_int32 Gains_Q16[MAX_NB_SUBFR],
+    const opus_int pitchL[MAX_NB_SUBFR], const opus_int Lambda_Q10,
+    const opus_int LTP_scale_Q14);
+#endif
+
+#if !defined(OPUS_HAVE_RTCD)
+#define OVERRIDE_silk_NSQ_del_dec (1)
+#define silk_NSQ_del_dec(psEncC, NSQ, psIndices, x16, pulses, PredCoef_Q12,  \
+                         LTPCoef_Q14, AR_Q13, HarmShapeGain_Q14, Tilt_Q14,   \
+                         LF_shp_Q14, Gains_Q16, pitchL, Lambda_Q10,          \
+                         LTP_scale_Q14, arch)                                \
+    ((void)(arch),                                                           \
+     PRESUME_NEON(silk_NSQ_del_dec)(                                         \
+         psEncC, NSQ, psIndices, x16, pulses, PredCoef_Q12, LTPCoef_Q14,     \
+         AR_Q13, HarmShapeGain_Q14, Tilt_Q14, LF_shp_Q14, Gains_Q16, pitchL, \
+         Lambda_Q10, LTP_scale_Q14))
+#endif
+
+#if !defined(OVERRIDE_silk_NSQ_del_dec)
+/*Is run-time CPU detection enabled on this platform?*/
+#if defined(OPUS_HAVE_RTCD) && (defined(OPUS_ARM_MAY_HAVE_NEON_INTR) && \
+                                !defined(OPUS_ARM_PRESUME_NEON_INTR))
+extern void (*const SILK_NSQ_DEL_DEC_IMPL[OPUS_ARCHMASK + 1])(
+    const silk_encoder_state *psEncC, silk_nsq_state *NSQ,
+    SideInfoIndices *psIndices, const opus_int16 x16[], opus_int8 pulses[],
+    const opus_int16 PredCoef_Q12[2 * MAX_LPC_ORDER],
+    const opus_int16 LTPCoef_Q14[LTP_ORDER * MAX_NB_SUBFR],
+    const opus_int16 AR_Q13[MAX_NB_SUBFR * MAX_SHAPE_LPC_ORDER],
+    const opus_int HarmShapeGain_Q14[MAX_NB_SUBFR],
+    const opus_int Tilt_Q14[MAX_NB_SUBFR],
+    const opus_int32 LF_shp_Q14[MAX_NB_SUBFR],
+    const opus_int32 Gains_Q16[MAX_NB_SUBFR],
+    const opus_int pitchL[MAX_NB_SUBFR], const opus_int Lambda_Q10,
+    const opus_int LTP_scale_Q14);
+#define OVERRIDE_silk_NSQ_del_dec (1)
+#define silk_NSQ_del_dec(psEncC, NSQ, psIndices, x16, pulses, PredCoef_Q12, \
+                         LTPCoef_Q14, AR_Q13, HarmShapeGain_Q14, Tilt_Q14,  \
+                         LF_shp_Q14, Gains_Q16, pitchL, Lambda_Q10,         \
+                         LTP_scale_Q14, arch)                               \
+    ((*SILK_NSQ_DEL_DEC_IMPL[(arch)&OPUS_ARCHMASK])(                        \
+        psEncC, NSQ, psIndices, x16, pulses, PredCoef_Q12, LTPCoef_Q14,     \
+        AR_Q13, HarmShapeGain_Q14, Tilt_Q14, LF_shp_Q14, Gains_Q16, pitchL, \
+        Lambda_Q10, LTP_scale_Q14))
+#elif defined(OPUS_ARM_PRESUME_NEON_INTR)
+#define OVERRIDE_silk_NSQ_del_dec (1)
+#define silk_NSQ_del_dec(psEncC, NSQ, psIndices, x16, pulses, PredCoef_Q12,   \
+                         LTPCoef_Q14, AR_Q13, HarmShapeGain_Q14, Tilt_Q14,    \
+                         LF_shp_Q14, Gains_Q16, pitchL, Lambda_Q10,           \
+                         LTP_scale_Q14, arch)                                 \
+    ((void)(arch),                                                            \
+     silk_NSQ_del_dec_neon(psEncC, NSQ, psIndices, x16, pulses, PredCoef_Q12, \
+                           LTPCoef_Q14, AR_Q13, HarmShapeGain_Q14, Tilt_Q14,  \
+                           LF_shp_Q14, Gains_Q16, pitchL, Lambda_Q10,         \
+                           LTP_scale_Q14))
+#endif
+#endif
+
+#endif /* end SILK_NSQ_DEL_DEC_ARM_H */

silk/arm/arm_silk_map.c

@@ -28,6 +28,7 @@ POSSIBILITY OF SUCH DAMAGE.
 # include "config.h"
 #endif
 
+#include "main_FIX.h"
 #include "NSQ.h"
 
 #if defined(OPUS_HAVE_RTCD)
@@ -35,6 +36,29 @@ POSSIBILITY OF SUCH DAMAGE.
 # if (defined(OPUS_ARM_MAY_HAVE_NEON_INTR) && \
  !defined(OPUS_ARM_PRESUME_NEON_INTR))
 
+void  (*const SILK_NSQ_DEL_DEC_IMPL[OPUS_ARCHMASK + 1])(
+        const silk_encoder_state    *psEncC,                                    /* I    Encoder State                   */
+        silk_nsq_state              *NSQ,                                       /* I/O  NSQ state                       */
+        SideInfoIndices             *psIndices,                                 /* I/O  Quantization Indices            */
+        const opus_int16            x16[],                                      /* I    Input                           */
+        opus_int8                   pulses[],                                   /* O    Quantized pulse signal          */
+        const opus_int16            PredCoef_Q12[ 2 * MAX_LPC_ORDER ],          /* I    Short term prediction coefs     */
+        const opus_int16            LTPCoef_Q14[ LTP_ORDER * MAX_NB_SUBFR ],    /* I    Long term prediction coefs      */
+        const opus_int16            AR_Q13[ MAX_NB_SUBFR * MAX_SHAPE_LPC_ORDER ], /* I Noise shaping coefs              */
+        const opus_int              HarmShapeGain_Q14[ MAX_NB_SUBFR ],          /* I    Long term shaping coefs         */
+        const opus_int              Tilt_Q14[ MAX_NB_SUBFR ],                   /* I    Spectral tilt                   */
+        const opus_int32            LF_shp_Q14[ MAX_NB_SUBFR ],                 /* I    Low frequency shaping coefs     */
+        const opus_int32            Gains_Q16[ MAX_NB_SUBFR ],                  /* I    Quantization step sizes         */
+        const opus_int              pitchL[ MAX_NB_SUBFR ],                     /* I    Pitch lags                      */
+        const opus_int              Lambda_Q10,                                 /* I    Rate/distortion tradeoff        */
+        const opus_int              LTP_scale_Q14                               /* I    LTP state scaling               */
+) = {
+      silk_NSQ_del_dec_c,              /* ARMv4 */
+      silk_NSQ_del_dec_c,              /* EDSP */
+      silk_NSQ_del_dec_c,              /* Media */
+      MAY_HAVE_NEON(silk_NSQ_del_dec), /* Neon */
+};
+
 /*There is no table for silk_noise_shape_quantizer_short_prediction because the
    NEON version takes different parameters than the C version.
   Instead RTCD is done via if statements at the call sites.

silk/main.h

@@ -42,6 +42,10 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "x86/main_sse.h"
 #endif
 
+#if (defined(OPUS_ARM_ASM) || defined(OPUS_ARM_MAY_HAVE_NEON_INTR))
+#include "arm/NSQ_del_dec_arm.h"
+#endif
+
 /* Convert Left/Right stereo signal to adaptive Mid/Side representation */
 void silk_stereo_LR_to_MS(
     stereo_enc_state            *state,                         /* I/O  State                                       */

silk_headers.mk

@@ -27,6 +27,7 @@ silk/arm/macros_armv5e.h \
 silk/arm/macros_arm64.h \
 silk/arm/SigProc_FIX_armv4.h \
 silk/arm/SigProc_FIX_armv5e.h \
+silk/arm/NSQ_del_dec_arm.h \
 silk/arm/NSQ_neon.h \
 silk/fixed/main_FIX.h \
 silk/fixed/structs_FIX.h \

silk_sources.mk

@@ -85,6 +85,7 @@ silk/x86/VQ_WMat_EC_sse.c
 
 SILK_SOURCES_ARM_NEON_INTR = \
 silk/arm/arm_silk_map.c \
+silk/arm/NSQ_del_dec_neon_intr.c \
 silk/arm/NSQ_neon.c
 
 SILK_SOURCES_FIXED = \