1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
|
;;; Simple mono flanger
;;; Author:Daniel Bertrand
;;; Date: May 29,2000
;;; 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.
;;; References:
;;; http://www.harmony-central.com/Effects/Articles/Flanging/
;;; speed( formerly "delta")=2*pi*freq/48000
;;; this give us our delta value for a specific freq (0.1-0.3Hz is good)
include "emu_constants.asm"
name "flanger"
in IO
out equ in
speed control 2e-05 , 0 , 1e-4 ; Controls frequency (radians)
delay control &7e-3 ,$1600 , 20e-3 ; twice (2*) average delay (sec)
width control #0.33 ,0 ,0.5 ; width control
forward control #1 ,0 ,#1 ; forward mix
feedback control 0.3 ,0 ,0.5 ; feedback level
;; sine generator storage spaces:
sinx sta 0
cosx sta #0.5
tmp dyn
tmp2 dyn
;;; Two Delay Lines:
dly delay &20e-3 ;20msec delay line
write twrite dly,0 ; tram writes
ready tread dly,0 ; tram reads
reada tread dly,0
;;;The code:
;;; two opcode sinewave generator (I love this chip!):
macs sinx,sinx,speed,cosx
macs1 cosx,cosx,speed,sinx
;;; 0.5Asint+0.5:
macs tmp,C_2^30,sinx,width
;;; calculate address:
macs ready.a,write.a,delay,tmp
;second addresses for interpolation:
;(interesting how the emu engineers decided that $800 wasn't a needed value)
macints reada.a,ready.a,C_8,C_256
;;; output values:
;;; 0x55 is 00100000 (?)
macints tmp,C_0,reada.a,C_LSshift; get least significant part of address
interp tmp2,ready,tmp,reada ;interpolate in-between the two delay line readings
macs out,in,tmp2,forward
;;; feedback and write to the delay line:
macs write,in,tmp2,feedback
end
|
