Optimized DSP sample out functions for armv6. (For stereo output) ~9% faster than SVN asm and about 4% faster than SVN asm rearranged to observe pipeline hazards.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@25717 a1c6a512-1295-4272-9138-f99709370657

3 files changed, 134 insertions, 1 deletions

diff --git a/apps/SOURCES b/apps/SOURCES
index 7bc263a153..66f2a7da51 100644
--- a/apps/SOURCES
+++ b/apps/SOURCES
@@ -158,6 +158,9 @@ dsp_cf.S
 eq_cf.S         
 #elif defined(CPU_ARM)
 dsp_arm.S
+#if ARM_ARCH >= 6
+dsp_arm_v6.S
+#endif
 eq_arm.S
 #endif
 #endif
diff --git a/apps/dsp_arm.S b/apps/dsp_arm.S
index b90e632782..f924569bc5 100644
--- a/apps/dsp_arm.S
+++ b/apps/dsp_arm.S
@@ -18,6 +18,7 @@
  * KIND, either express or implied.
  *
  ****************************************************************************/
+ #include "config.h"
 
 /****************************************************************************
  *  void channels_process_sound_chan_mono(int count, int32_t *buf[])
@@ -83,7 +84,8 @@ channels_process_sound_chan_karaoke:
     ldmfd   sp!, {r4-r5, pc}
 .karaokeend:
     .size   channels_process_sound_chan_karaoke,.karaokeend-channels_process_sound_chan_karaoke
-    
+
+#if ARM_ARCH < 6
 /****************************************************************************
  *  void sample_output_mono(int count, struct dsp_data *data,
  *                          const int32_t *src[], int16_t *dst)
@@ -195,6 +197,7 @@ sample_output_stereo:
     ldmfd   sp!, {r4-r10, pc}
 .sosend:
     .size   sample_output_stereo,.sosend-sample_output_stereo
+#endif /* ARM_ARCH < 6 */    
 
 /****************************************************************************
  * void apply_crossfeed(int count, int32_t* src[])
diff --git a/apps/dsp_arm_v6.S b/apps/dsp_arm_v6.S
new file mode 100644
index 0000000000..39949498ea
--- /dev/null
+++ b/apps/dsp_arm_v6.S
@@ -0,0 +1,127 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2010 Michael Sevakis
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ *  void sample_output_mono(int count, struct dsp_data *data,
+ *                          const int32_t *src[], int16_t *dst)
+ */
+    .section .text, "ax", %progbits
+    .align  2
+    .global sample_output_mono
+    .type   sample_output_mono, %function
+sample_output_mono:
+    @ input: r0 = count, r1 = data, r2 = src, r3 = dst
+    stmfd   sp!, { r4, lr }            @
+                                       @
+    ldr     r1, [r1]                   @ r1 = data->output_scale
+    ldr     r2, [r2]                   @ r2 = src[0]
+                                       @
+    mov     r4, #1                     @ r4 = 1 << (scale - 1)
+    mov     r4, r4, lsl r1             @
+    subs    r0, r0, #1                 @ odd: end at 0; even: end at -1
+    mov     r4, r4, lsr #1             @
+    beq     2f                         @ Zero? Only one sample!
+                                       @
+1:                                     @
+    ldmia   r2!, { r12, r14 }          @ load Mi0, Mi1
+    qadd    r12, r12, r4               @ round, scale, saturate and
+    qadd    r14, r14, r4               @ pack Mi0 to So0, Mi1 to So1
+    mov     r12, r12, asr r1           @
+    mov     r14, r14, asr r1           @
+    ssat    r12, #16, r12              @
+    ssat    r14, #16, r14              @
+    pkhbt   r12, r12, r12, asl #16     @
+    pkhbt   r14, r14, r14, asl #16     @
+    subs    r0, r0, #2                 @
+    stmia   r3!, { r12, r14 }          @ store So0, So1
+    bgt     1b                         @
+                                       @
+    ldmltfd sp!, { r4, pc }            @ if count was even, we're done
+                                       @
+2:                                     @
+    ldr     r12, [r2]                  @ round, scale, saturate
+    qadd    r12, r12, r4               @ and pack Mi to So
+    mov     r12, r12, asr r1           @
+    ssat    r12, #16, r12              @
+    pkhbt   r12, r12, r12, asl #16     @
+    str     r12, [r3]                  @ store So
+                                       @       
+    ldmfd   sp!, { r4, pc }            @
+    .size   sample_output_mono, .-sample_output_mono
+
+/****************************************************************************
+ * void sample_output_stereo(int count, struct dsp_data *data,
+ *                           const int32_t *src[], int16_t *dst)
+ */
+    .section .text, "ax", %progbits
+    .align  2
+    .global sample_output_stereo
+    .type   sample_output_stereo, %function
+sample_output_stereo:
+    @ input: r0 = count, r1 = data, r2 = src, r3 = dst
+    stmfd   sp!, { r4-r7, lr }         @
+                                       @
+    ldr     r1, [r1]                   @ r1 = data->output_scale    
+    ldmia   r2, { r2, r4 }             @ r2 = src[0], r4 = src[1]
+                                       @
+    mov     r5, #1                     @ r5 = 1 << (scale - 1)
+    mov     r5, r5, lsl r1             @
+    subs    r0, r0, #1                 @ odd: end at 0; even: end at -1
+    mov     r5, r5, lsr #1             @
+    beq     2f                         @ Zero? Only one sample!
+                                       @
+1:                                     @
+    ldmia   r2!, { r6, r7 }            @ r6, r7 = Li0, Li1
+    ldmia   r4!, { r12, r14 }          @ r12, r14 = Ri0, Ri1
+    qadd    r6, r6, r5                 @ round, scale, saturate and pack
+    qadd    r7, r7, r5                 @ Li0+Ri0 to So0, Li1+Ri1 to So1
+    qadd    r12, r12, r5               @
+    qadd    r14, r14, r5               @
+    mov     r6, r6, asr r1             @ 
+    mov     r7, r7, asr r1             @
+    mov     r12, r12, asr r1           @
+    mov     r14, r14, asr r1           @
+    ssat    r6, #16, r6                @
+    ssat    r12, #16, r12              @
+    ssat    r7, #16, r7                @
+    ssat    r14, #16, r14              @
+    pkhbt   r6, r6, r12, asl #16       @
+    pkhbt   r7, r7, r14, asl #16       @
+    subs    r0, r0, #2                 @
+    stmia   r3!, { r6, r7 }            @ store So0, So1
+    bgt     1b                         @
+                                       @
+    ldmltfd sp!, { r4-r7, pc }         @ if count was even, we're done
+                                       @
+2:                                     @
+    ldr     r6, [r2]                   @ r6 = Li
+    ldr     r12, [r4]                  @ r12 = Ri
+    qadd    r6, r6, r5                 @ round, scale, saturate
+    qadd    r12, r12, r5               @ and pack Li+Ri to So
+    mov     r6, r6, asr r1             @
+    mov     r12, r12, asr r1           @
+    ssat    r6, #16, r6                @
+    ssat    r12, #16, r12              @
+    pkhbt   r6, r6, r12, asl #16       @
+    str     r6, [r3]                   @ store So
+                                       @
+    ldmfd   sp!, { r4-r7, pc }         @
+    .size   sample_output_stereo, .-sample_output_stereo