;
; SID registers
;

            .virtual
_sid            .struct
_sid_voice        .struct
freq            .word ?
duty            .word ?
ctrl            .byte ?
ad            .byte ?
sr            .byte ?
            .endstruct
voice1            .dstruct _sid_voice
voice2            .dstruct _sid_voice
voice3            .dstruct _sid_voice
ffreq            .word ?
fres            .byte ?
volume            .byte ?
potx            .byte ?
poty            .byte ?
osc3            .byte ?
env3            .byte ?
            .endstruct
            .endvirtual

PAL_CLOCK        = 985248
NTSC_CLOCK        = 1022727

sid_freq .sfunction freq, clock=PAL_CLOCK, int(freq*16777216/clock)
sid_duty .sfunction duty, int(duty*(1<<12))

SID_CTRL_NOISE        = %1000_0000
SID_CTRL_PULSE        = %0100_0000
SID_CTRL_SAWTOOTH   = %0010_0000
SID_CTRL_TRIANGLE   = %0001_0000
SID_CTRL_TEST        = %0000_1000
SID_CTRL_RING        = %0000_0100
SID_CTRL_SYNC        = %0000_0010
SID_CTRL_GATE        = %0000_0001

SID_RES_EXT        = %0000_1000
SID_RES_V3        = %0000_0100
SID_RES_V2        = %0000_0010
SID_RES_V1        = %0000_0001

SID_FILTER_MUTE3    = %1000_0000
SID_FILTER_HIGHPASS = %0100_0000
SID_FILTER_BANDPASS = %0010_0000
SID_FILTER_LOWPASS  = %0001_0000

; vim: syntax=64tass