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cc65/libsrc/pce/psg.s
2015-09-04 14:14:17 +02:00

31 lines
888 B
ArmAsm

.include "pce.inc"
.export psg_init
psg_init:
clx
stz PSG_GLOBAL_PAN ; Clear global balance
psg_clear_loop:
stx PSG_CHAN_SELECT ; Select channel
stz PSG_FREQ_LO ; Clear frequency LSB
stz PSG_FREQ_HI ; Clear frequency MSB
stz PSG_CHAN_CTRL ; Clear volume
stz PSG_CHAN_PAN ; Clear balance
stz PSG_NOISE ; Clear noise control
stz PSG_LFO_FREQ ; Clear LFO frequency
stz PSG_LFO_CTRL ; Clear LFO control
cly
psg_clear_waveform:
stz PSG_CHAN_DATA ; Clear waveform byte
iny
cpy #$20
bne psg_clear_waveform
inx
cpx #$06
bne psg_clear_loop
rts