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Assembler optimised LPC routines for Coldfire. Will enable them when codec has seen further testing.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@7657 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Thom Johansen 2005-10-27 00:33:38 +00:00
parent 273d2e81f7
commit 0b38c7dcbe
2 changed files with 245 additions and 0 deletions

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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2005 by Thom Johansen
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
/* The following is an assembler optimised version of the LPC filtering
routines needed for FLAC decoding. It is optimised for use with the
MCF5249 processor, or any other similar ColdFire core with the EMAC unit.
All LPC filtering up to order 8 is done in specially optimised unrolled
loops, while every order above this is handled by a slower default routine.
*/
.text
.global lpc_decode_emac
.align 2
lpc_decode_emac:
lea.l (-40, %sp), %sp
movem.l %d2-%d7/%a2-%a5, (%sp)
movem.l (40+4, %sp), %d0-%d2/%a0-%a1
/* d0 = blocksize, d1 = qlevel, d2 = pred_order
a0 = data, a1 = coeffs
*/
/* the data pointer always lags behind history pointer by 'pred_order'
samples. since we have one loop for each order, we can hard code this
and free a register by not saving data pointer.
*/
move.l %d2, %d3
neg.l %d3
lea.l (%a0, %d3.l*4), %a0 | history
clr.l %d3
move.l %d3, %macsr | we'll need integer mode for this
tst.l %d0
jeq .exit | zero samples to process, exit
moveq.l #8, %d3
cmp.l %d3, %d2
jgt .default | order is over 8, jump to default case
lea.l .jumptable, %a4
move.l (%a4, %d2.l*4), %a4
jmp (%a4)
.align 4 | avoid unaligned fetch
.jumptable:
.long .exit
.long .order1
.long .order2
.long .order3
.long .order4
.long .order5
.long .order6
.long .order7
.long .order8
.order8:
movem.l (%a1), %d3-%d7/%a2-%a4 | load lpc coefs
move.l (%a0)+, %a5 | load first history sample
.loop8:
mac.l %a5, %a4, (%a0)+, %a5, %acc0
mac.l %a5, %a3, (%a0)+, %a5, %acc0
mac.l %a5, %a2, (%a0)+, %a5, %acc0
mac.l %a5, %d7, (%a0)+, %a5, %acc0
mac.l %a5, %d6, (%a0)+, %a5, %acc0
mac.l %a5, %d5, (%a0)+, %a5, %acc0
mac.l %a5, %d4, (%a0)+, %a5, %acc0
mac.l %a5, %d3, (-7*4, %a0), %a5, %acc0 | load for the next iteration
movclr.l %acc0, %d2 | get sum
asr.l %d1, %d2 | shift sum by lp_quantization bits
add.l %d2, (%a0) | add residual and save
lea.l (-6*4, %a0), %a0 | history pointer points at second element
subq.l #1, %d0 | decrement counter
jne .loop8 | are we done?
jra .exit
.order7:
movem.l (%a1), %d3-%d7/%a2-%a3
move.l (%a0)+, %a5
.loop7:
mac.l %a5, %a3, (%a0)+, %a5, %acc0
mac.l %a5, %a2, (%a0)+, %a5, %acc0
mac.l %a5, %d7, (%a0)+, %a5, %acc0
mac.l %a5, %d6, (%a0)+, %a5, %acc0
mac.l %a5, %d5, (%a0)+, %a5, %acc0
mac.l %a5, %d4, (%a0)+, %a5, %acc0
mac.l %a5, %d3, (-6*4, %a0), %a5, %acc0
movclr.l %acc0, %d2
asr.l %d1, %d2
add.l %d2, (%a0)
lea.l (-5*4, %a0), %a0
subq.l #1, %d0
jne .loop7
jra .exit
.order6:
movem.l (%a1), %d3-%d7/%a2
move.l (%a0)+, %a5
.loop6:
mac.l %a5, %a2, (%a0)+, %a5, %acc0
mac.l %a5, %d7, (%a0)+, %a5, %acc0
mac.l %a5, %d6, (%a0)+, %a5, %acc0
mac.l %a5, %d5, (%a0)+, %a5, %acc0
mac.l %a5, %d4, (%a0)+, %a5, %acc0
mac.l %a5, %d3, (-5*4, %a0), %a5, %acc0
movclr.l %acc0, %d2
asr.l %d1, %d2
add.l %d2, (%a0)
lea.l (-4*4, %a0), %a0
subq.l #1, %d0
jne .loop6
jra .exit
.order5:
movem.l (%a1), %d3-%d7
move.l (%a0)+, %a5
.loop5:
mac.l %a5, %d7, (%a0)+, %a5, %acc0
mac.l %a5, %d6, (%a0)+, %a5, %acc0
mac.l %a5, %d5, (%a0)+, %a5, %acc0
mac.l %a5, %d4, (%a0)+, %a5, %acc0
mac.l %a5, %d3, (-4*4, %a0), %a5, %acc0
movclr.l %acc0, %d2
asr.l %d1, %d2
add.l %d2, (%a0)
lea.l (-3*4, %a0), %a0
subq.l #1, %d0
jne .loop5
jra .exit
.order4:
movem.l (%a1), %d3-%d6
move.l (%a0)+, %a5
.loop4:
mac.l %a5, %d6, (%a0)+, %a5, %acc0
mac.l %a5, %d5, (%a0)+, %a5, %acc0
mac.l %a5, %d4, (%a0)+, %a5, %acc0
mac.l %a5, %d3, (-3*4, %a0), %a5, %acc0
movclr.l %acc0, %d2
asr.l %d1, %d2
add.l %d2, (%a0)
subq.l #8, %a0
subq.l #1, %d0
jne .loop4
jra .exit
.order3:
movem.l (%a1), %d3-%d5
move.l (%a0)+, %a5
.loop3:
mac.l %a5, %d5, (%a0)+, %a5, %acc0
mac.l %a5, %d4, (%a0)+, %a5, %acc0
mac.l %a5, %d3, (-2*4, %a0), %a5, %acc0
movclr.l %acc0, %d2
asr.l %d1, %d2
add.l %d2, (%a0)
subq.l #4, %a0
subq.l #1, %d0
jne .loop3
jra .exit
.order2:
movem.l (%a1), %d3-%d4
move.l (%a0)+, %a5
.loop2:
mac.l %a5, %d4, (%a0)+, %a5, %acc0
mac.l %a5, %d3, %acc0 | data for next iteration is already loaded
movclr.l %acc0, %d2
asr.l %d1, %d2
add.l %d2, (%a0)
subq.l #1, %d0
jne .loop2
jra .exit
.order1:
| no point in using mac here
move.l (%a1), %d3
.loop1:
move.l %d3, %d2
muls.l (%a0)+, %d2
asr.l %d1, %d2
add.l %d2, (%a0)
subq.l #1, %d0
jne .loop1
jra .exit
.default:
/* we do the filtering in an unrolled by 4 loop as far as we can, and then
do the rest in an ordinary one by one sample loop.
*/
lea.l (%a1, %d2.l*4), %a2 | need to start in the other end of coefs
move.l %a0, %a3 | working copy of history pointer
move.l %d2, %d3
lsr.l #2, %d3 | coefs/4, num of iterations needed in next loop
move.l (%a3)+, %a5 | preload data for loop
.dloop1:
lea.l (-4*4, %a2), %a2 | move lpc coef pointer four samples backwards
movem.l (%a2), %d4-%d7 | load four coefs
mac.l %a5, %d7, (%a3)+, %a5, %acc0
mac.l %a5, %d6, (%a3)+, %a5, %acc0
mac.l %a5, %d5, (%a3)+, %a5, %acc0
mac.l %a5, %d4, (%a3)+, %a5, %acc0
subq.l #1, %d3 | any more unrolled loop operations left?
jne .dloop1
move.l %d2, %d3
moveq.l #3, %d4 | mask 0x00000003
and.l %d4, %d3 | get the remaining samples to be filtered
jeq .dsave | no remaining samples
.dloop2:
move.l -(%a2), %d4 | get lpc coef
mac.l %a5, %d4, (%a3)+, %a5, %acc0
subq.l #1, %d3 | any more iterations left?
jne .dloop2
.dsave:
movclr.l %acc0, %d3 | get result
asr.l %d1, %d3 | shift lp_quantization bits right
subq.l #4, %a3 | we're one past the save location
add.l %d3, (%a3) | add residual and save
addq.l #4, %a0 | increment history pointer
subq.l #1, %d0 | decrement data_len
jne .default | are we done?
| if so, fall through to exit
.exit:
movem.l (%sp), %d2-%d7/%a2-%a5
lea.l (40, %sp), %sp
rts

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#ifndef _FLAC_COLDFIRE_H
#define _FLAC_COLDFIRE_H
#include "bitstream.h"
void lpc_decode_emac(int blocksize, int qlevel, int pred_order, int32_t* data, int* coeffs);
#endif