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c33aafcd5c
GCC cannot compile the existing assembly here on ARMv7-M, claiming impossible constraints. It is actually possible to compile if the input arguments (addresses and sizes) are first moved to a high register so as not to conflict with the use of r0-r7 in ldm/stm -- this is exactly what GCC does for ARMv6, but it won't do it on ARMv7-M for some reason. We can get a result similar to the ARMv6 code by manually moving the inputs into temporaries, but the generated code is a actually a bit smaller on ARMv7-M if the r0-r7 block is shifted up to r3-r10. This only works since ARMv7-M supports the 32-bit Thumb encoding -- 16-bit Thumb can't represent an ldm/stm instruction of this type. It's worth #ifdef'ing the code because although the ARMv7-M version works on ARMv6 too, it spills a lot of registers on the stack even though register use is mostly similar. Change-Id: I9bc8b5c76e198aecfd0a0e7a2158b1c00f82c4df
140 lines
5.2 KiB
C
140 lines
5.2 KiB
C
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2011 by Michael Sevakis
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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#define MIXER_OPTIMIZED_MIX_SAMPLES
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#define MIXER_OPTIMIZED_WRITE_SAMPLES
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/* Mix channels' samples and apply gain factors */
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static FORCE_INLINE void mix_samples(void *out,
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const void *src0,
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int32_t src0_amp,
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const void *src1,
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int32_t src1_amp,
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size_t size)
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{
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uint32_t s0, s1;
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if (src0_amp == MIX_AMP_UNITY && src1_amp == MIX_AMP_UNITY)
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{
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/* Both are unity amplitude */
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asm volatile (
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"1: \n"
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"ldr %4, [%1], #4 \n"
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"ldr %5, [%2], #4 \n"
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"subs %3, %3, #4 \n"
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"qadd16 %5, %5, %4 \n"
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"str %5, [%0], #4 \n"
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"bhi 1b \n"
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: "+r"(out), "+r"(src0), "+r"(src1), "+r"(size),
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"=&r"(s0), "=&r"(s1));
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}
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else
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{
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/* One or neither are unity amplitude */
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uint32_t tmp;
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asm volatile (
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"1: \n"
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"ldr %4, [%1], #4 \n"
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"ldr %5, [%2], #4 \n"
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"subs %3, %3, #4 \n"
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"smulwb %6, %7, %4 \n"
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"smulwt %4, %7, %4 \n"
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"smlawb %6, %8, %5, %6 \n"
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"smlawt %4, %8, %5, %4 \n"
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"ssat %6, #16, %6 \n"
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"ssat %4, #16, %4 \n"
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"pkhbt %6, %6, %4, asl #16 \n"
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"str %6, [%0], #4 \n"
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"bhi 1b \n"
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: "+r"(out), "+r"(src0), "+r"(src1), "+r"(size),
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"=&r"(s0), "=&r"(s1), "=&r"(tmp)
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: "r"(src0_amp), "r"(src1_amp));
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}
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}
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/* Write channel's samples and apply gain factor */
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static FORCE_INLINE void write_samples(void *out,
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const void *src,
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int32_t amp,
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size_t size)
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{
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if (LIKELY(amp == MIX_AMP_UNITY))
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{
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/* Channel is unity amplitude */
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#if defined(CPU_ARM_MICRO) && ARCH_VERSION >= 7
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asm volatile (
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"ands r4, %2, #0x1f \n"
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"beq 2f \n"
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"1: \n"
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"ldr r3, [%1], #4 \n"
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"subs r4, r4, #4 \n"
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"str r3, [%0], #4 \n"
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"bne 1b \n"
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"bics %2, %2, #0x1f \n"
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"beq 3f \n"
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"2: \n"
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"ldmia %1!, { r3-r10 } \n"
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"subs %2, %2, #32 \n"
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"stmia %0!, { r3-r10 } \n"
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"bhi 2b \n"
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"3: \n"
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: "+lr"(out), "+lr"(src), "+r"(size)
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:
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: "r3", "r4", "r5", "r6", "r7", "r8", "r9", "r10");
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#else
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asm volatile (
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"ands r1, %2, #0x1f \n"
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"beq 2f \n"
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"1: \n"
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"ldr r0, [%1], #4 \n"
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"subs r1, r1, #4 \n"
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"str r0, [%0], #4 \n"
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"bne 1b \n"
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"bics %2, %2, #0x1f \n"
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"beq 3f \n"
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"2: \n"
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"ldmia %1!, { r0-r7 } \n"
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"subs %2, %2, #32 \n"
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"stmia %0!, { r0-r7 } \n"
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"bhi 2b \n"
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"3: \n"
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: "+r"(out), "+r"(src), "+r"(size)
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:
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: "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7");
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#endif
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}
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else
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{
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/* Channel needs amplitude cut */
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uint32_t s, tmp;
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asm volatile(
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"1: \n"
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"ldr %3, [%1], #4 \n"
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"subs %2, %2, #4 \n"
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"smulwt %4, %5, %3 \n"
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"smulwb %3, %5, %3 \n"
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"pkhbt %4, %3, %4, asl #16 \n"
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"str %4, [%0], #4 \n"
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"bhi 1b \n"
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: "+r"(out), "+r"(src), "+r"(size),
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"=&r"(s), "=&r"(tmp)
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: "r"(amp));
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}
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}
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