rockbox/firmware/target/arm/pcm-mixer-armv6.c

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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2011 by 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.
*
****************************************************************************/
#define MIXER_OPTIMIZED_MIX_SAMPLES
#define MIXER_OPTIMIZED_WRITE_SAMPLES
/* Mix channels' samples and apply gain factors */
static FORCE_INLINE void mix_samples(void *out,
void *src0,
int32_t src0_amp,
void *src1,
int32_t src1_amp,
size_t size)
{
uint32_t s0, s1;
if (src0_amp == MIX_AMP_UNITY && src1_amp == MIX_AMP_UNITY)
{
/* Both are unity amplitude */
asm volatile (
"1: \n"
"ldr %4, [%1], #4 \n"
"ldr %5, [%2], #4 \n"
"subs %3, %3, #4 \n"
"qadd16 %5, %5, %4 \n"
"str %5, [%0], #4 \n"
"bhi 1b \n"
: "+r"(out), "+r"(src0), "+r"(src1), "+r"(size),
"=&r"(s0), "=&r"(s1));
}
else
{
/* One or neither are unity amplitude */
uint32_t tmp;
asm volatile (
"1: \n"
"ldr %4, [%1], #4 \n"
"ldr %5, [%2], #4 \n"
"subs %3, %3, #4 \n"
"smulwb %6, %7, %4 \n"
"smulwt %4, %7, %4 \n"
"smlawb %6, %8, %5, %6 \n"
"smlawt %4, %8, %5, %4 \n"
"ssat %6, #16, %6 \n"
"ssat %4, #16, %4 \n"
"pkhbt %6, %6, %4, asl #16 \n"
"str %6, [%0], #4 \n"
"bhi 1b \n"
: "+r"(out), "+r"(src0), "+r"(src1), "+r"(size),
"=&r"(s0), "=&r"(s1), "=&r"(tmp)
: "r"(src0_amp), "r"(src1_amp));
}
}
/* Write channel's samples and apply gain factor */
static FORCE_INLINE void write_samples(void *out,
void *src,
int32_t amp,
size_t size)
{
if (LIKELY(amp == MIX_AMP_UNITY))
{
/* Channel is unity amplitude */
asm volatile (
"ands r1, %2, #0x1f \n"
"beq 2f \n"
"1: \n"
"ldr r0, [%1], #4 \n"
"subs r1, r1, #4 \n"
"str r0, [%0], #4 \n"
"bne 1b \n"
"bics %2, %2, #0x1f \n"
"beq 3f \n"
"2: \n"
"ldmia %1!, { r0-r7 } \n"
"subs %2, %2, #32 \n"
"stmia %0!, { r0-r7 } \n"
"bhi 2b \n"
"3: \n"
: "+r"(out), "+r"(src), "+r"(size)
:
: "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7");
}
else
{
/* Channel needs amplitude cut */
uint32_t s, tmp;
asm volatile(
"1: \n"
"ldr %3, [%1], #4 \n"
"subs %2, %2, #4 \n"
"smulwt %4, %5, %3 \n"
"smulwb %3, %5, %3 \n"
"pkhbt %4, %3, %4, asl #16 \n"
"str %4, [%0], #4 \n"
"bhi 1b \n"
: "+r"(out), "+r"(src), "+r"(size),
"=&r"(s), "=&r"(tmp)
: "r"(amp));
}
}