8238b49c74
new options is appreciated. Thanks to Dan Everton for the settings/GUI code. git-svn-id: svn://svn.rockbox.org/rockbox/trunk@9609 a1c6a512-1295-4272-9138-f99709370657
85 lines
3.4 KiB
ArmAsm
85 lines
3.4 KiB
ArmAsm
/***************************************************************************
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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) 2006 Thom Johansen
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*
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* All files in this archive are subject to the GNU General Public License.
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* See the file COPYING in the source tree root for full license agreement.
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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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.section .text
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.global apply_crossfeed
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apply_crossfeed:
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lea.l (-44, %sp), %sp
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movem.l %d2-%d7/%a2-%a6, (%sp) | save all regs
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move.l (44+4, %sp), %a4
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movem.l (%a4), %a4-%a5 | a4 = src[0], a5 = src[1]
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move.l (44+8, %sp), %d7 | d7 = count
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lea.l crossfeed_data, %a1
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lea.l (8*4, %a1), %a0 | a0 = &delay[0][0]
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move.l (%a1)+, %a6 | a6 = direct gain
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movem.l (3*4, %a1), %d0-%d3 | fetch filter history samples
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move.l (33*4, %a1), %d4 | fetch delay line index
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movem.l (%a1), %a1-%a3 | load filter coefs
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move.l %d4, %d5
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lsl.l #3, %d5
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add.l %d5, %a0 | point a0 to current delay position
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| lea.l (%d4*4, %a0), %a0
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| lea.l (%d4*4, %a0), %a0 | point a0 to current delay position
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/* Register usage in loop:
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* a0 = &delay[index][0], a1..a3 = b0, b1, a1 (filter coefs),
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* a4 = src[0], a5 = src[1], a6 = direct gain,
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* d0..d3 = history
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* d4 = delay line index,
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* d5,d6 = temp.
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* d7 = count
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*/
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.cfloop:
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mac.l %a2, %d0, (4, %a0), %d0, %acc0 | acc = b1*dr[n - 1] d0 = dr[n]
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mac.l %a1, %d0, %acc0 | acc += b0*dr[n]
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mac.l %a3, %d1, (%a4), %d5, %acc0 | acc += a1*y_l[n - 1], load left input
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move.l %acc0, %d1 | get filtered delayed sample
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mac.l %a6, %d5, %acc0 | acc += gain*x_l[n]
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movclr.l %acc0, %d6
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move.l %d6, (%a4)+ | write result
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mac.l %a2, %d2, (%a0), %d2, %acc0 | acc = b1*dl[n - 1], d2 = dl[n]
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move.l %d5, (%a0)+ | save left input to delay line
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mac.l %a1, %d2, %acc0 | acc += b0*dl[n]
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mac.l %a3, %d3, (%a5), %d5, %acc0 | acc += a1*y_r[n - 1], load right input
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move.l %acc0, %d3 | get filtered delayed sample
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mac.l %a6, %d5, %acc0 | acc += gain*x_r[n]
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move.l %d5, (%a0)+ | save right input to delay line
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movclr.l %acc0, %d6
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move.l %d6, (%a5)+ | write result
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addq.l #1, %d4 | index++
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moveq.l #13, %d6
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cmp.l %d6, %d4 | wrap index to 0 if it overflows
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jlt .nowrap
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moveq.l #13*8, %d4
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sub.l %d4, %a0 | wrap back delay line ptr as well
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clr.l %d4
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.nowrap:
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subq.l #1, %d7
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jne .cfloop
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| save data back to struct
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lea.l crossfeed_data + 4*4, %a1
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movem.l %d0-%d3, (%a1)
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move.l %d4, (30*4, %a1)
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movem.l (%sp), %d2-%d7/%a2-%a6
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lea.l (44, %sp), %sp
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rts
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