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156 lines
4.1 KiB
NASM
156 lines
4.1 KiB
NASM
;; fv10k1.m4 - fv10k1 package
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;; This implements Jezar Wakefield's Freeverb algorithm
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;;
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;; Copyright (C) 2001 Oleg Smirnov <smirnov@astron.nl>
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;;
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;; This program is free software; you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation; either version 2 of the License, or
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;; (at your option) any later version.
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;;
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;; This program is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;;
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;; You should have received a copy of the GNU General Public License
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;; along with this program; if not, write to the Free Software
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;; Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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;;
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;; $Id: fv10k1.m4,v 1.1 2001/09/28 01:56:20 dbertrand Exp $
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name "Freeverb"
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include "emu_constants.inc"
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include "fv-routes.inc"
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include "fv-controls.inc"
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include "fv-basstreble.inc"
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; IO lines right/left
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ior io
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iol io
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; No room reflection support - load full set of Freeverb filters and put
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; them into ITRAM first
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include "fv-filters.inc"
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; delay lines for channel & reverb predelay will use XTRAM
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dlyr delay &2
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dlyl delay &2
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writer twrite dlyr,0
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writel twrite dlyl,0
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oreadr tread dlyr,64 ; use 64 samples to avoid some TRAM glitches
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oreadl tread dlyl,64
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revreadr tread dlyr,64
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revreadl tread dlyl,64
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input dyn 1 ; wet reverb input [== (inl+inr)*gain ]
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dly_b2 sta 0,0 ; storage for second bass/treble filter
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dly_t2 sta 0,0
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dly_b3 sta 0,0
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dly_t3 sta 0,0
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dly_b4 sta 0,0
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dly_t4 sta 0,0
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reflr dyn 2
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refll dyn 2
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reverbr dyn 1
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reverbl dyn 1
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ptr dyn 2
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ptl dyn 2
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;;; update TRAM read addresses from control GPRs
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acc3 oreadr.a,delay_r,writer.a,C_0
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acc3 oreadl.a,delay_l,writel.a,C_0
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acc3 revreadr.a,revdelay,writer.a,C_0
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acc3 revreadl.a,revdelay,writel.a,C_0
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;;; init reverb outputs (and clear ACCUM for code below)
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macs fvrev_l,C_0,C_0,C_0
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macs fvrev_r,C_0,C_0,C_0
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;;; accumulate reverb inputs ( predelayed R+L * revgain )
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;;; and at the same time pass input to output w/delay
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macmv ior,oreadr,revreadr,revgain
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macs input,ACCUM,revreadl,revgain
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acc3 iol,oreadl,C_0,C_0
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acc3 writer,ior,C_0,C_0
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acc3 writel,iol,C_0,C_0
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;;; apply & accumulate comb filters
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do_comb_filters fvrev_l,fvrev_r
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;;; apply allpass filters
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do_allpass_filters fvrev_l,fvrev_r
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;;; feed accumulated values to outputs, multiplying by wet & dry controls
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interp tmp,fvrev_l,wet1,fvrev_r
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interp tmpout,fvrev_r,wet1,fvrev_l
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macs fvrev_l,tmp,revreadl,dry
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macs fvrev_r,tmpout,revreadr,dry
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;;; apply bass/treble controls to output
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test revdefeat
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bne .skipbasstreble
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basstreble fvrev_l,fvrev_l,revbass,revtreble,dly_b1,dly_t1
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basstreble fvrev_r,fvrev_r,revbass,revtreble,dly_b2,dly_t2
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.skipbasstreble
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;;; reset level meters at specified interval (use DBAC to track it)
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andxor tmp,DBAC,level_interval,C_0
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bne .skipreset
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acc3 maxlev_fr,C_0,C_0,C_0
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acc3 maxlev_fl,C_0,C_0,C_0
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acc3 maxlev_rr,C_0,C_0,C_0
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acc3 maxlev_rl,C_0,C_0,C_0
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.skipreset
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;;; apply reflection levels and bass/treble
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macs reflr,C_0,fvrefl_fr,refl_f
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macs refll,C_0,fvrefl_fl,refl_f
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macs reflr,reflr,fvrefl_rr,refl_f ; two-speaker mode - add in other line
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macs refll,refll,fvrefl_rl,refl_f
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;;; apply reverb levels
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macs reverbr,C_0,fvrev_r,reverb_f
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macs reverbl,C_0,fvrev_l,reverb_f
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;;; write in+reverb_reflections to output
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;;; use macmv accumulation for extra precision
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makeoutput MACRO io,refl,reverb,passthru
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macs C_0,C_0,C_0,C_0
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macmv tmp,tmp,refl,C_max
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macmv tmp,C_0,io,ptf_level
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macs io,ACCUM,reverb,C_max
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ENDM
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makeoutput ior,reflr,reverbr,ptr
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makeoutput iol,refll,reverbl,ptl
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;;; maintain the maximum level
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maxlevel MACRO io,maxlev
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tstneg tmp,io,io,C_0 ; tmp = abs(io)
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limit maxlev,tmp,tmp,maxlev ; maxlevel=max(tmp,maxlevel)
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ENDM
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maxlevel ior.o,maxlev_fr
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maxlevel iol.o,maxlev_fl
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END
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