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iigs-game-engine
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Add hook for half and quarter speed updates

This commit is contained in:
Lucas Scharenbroich 2023-06-27 21:24:59 -05:00
parent cb5e9b0b25
commit a5af4c206c
1 changed files with 43 additions and 20 deletions
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63
demos/smb/apu.s
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@ -348,6 +348,8 @@ setup_interrupt = *
rts
interrupt_oscillator = 31
;reference_freq = 299 ; interrupt frequence (60Hz)
;reference_freq = 598 ; interrupt frequence (120Hz)
reference_freq = 1195 ; interrupt frequence (240Hz)
timer_sound_settings = * ; set up oscillator 30 for interrupts
dfb $00+interrupt_oscillator,reference_freq ; frequency low register
@ -523,6 +525,27 @@ tick_envelope
sta ]1+{APU_PULSE1_ENVELOPE-APU_PULSE1}
envelope_out <<<
half_frame_clock
; clock the length counters
clock_length_counter APU_PULSE1;#PULSE_HALT_FLAG
clock_length_counter APU_PULSE2;#PULSE_HALT_FLAG
clock_length_counter APU_TRIANGLE;#TRIANGLE_HALT_FLAG
clock_length_counter APU_NOISE;#NOISE_HALT_FLAG
; clock the sweep units
clock_sweep APU_PULSE1;0
clock_sweep APU_PULSE2;1
rts
quarter_frame_clock
; clock the envelopes and triangle linear counter
clock_linear_counter APU_TRIANGLE
clock_envelope APU_PULSE1
clock_envelope APU_PULSE2
clock_envelope APU_NOISE
rts
;-----------------------------------------------------------------------------------------
; interupt handler
;-----------------------------------------------------------------------------------------
@ -577,29 +600,29 @@ interrupt_handler = *
stx apu_frame_counter
jmp (:frame_counter_proc,x)
:frame_counter_proc da :quarter_frame,:half_frame,:quarter_frame,:no_frame,:half_frame
:half_frame
; clock the length counters
clock_length_counter APU_PULSE1;#PULSE_HALT_FLAG
clock_length_counter APU_PULSE2;#PULSE_HALT_FLAG
clock_length_counter APU_TRIANGLE;#TRIANGLE_HALT_FLAG
clock_length_counter APU_NOISE;#NOISE_HALT_FLAG
; Full speed emulation (240Hz)
:half_frame jsr half_frame_clock
:quarter_frame jsr quarter_frame_clock
; clock the sweep units
clock_sweep APU_PULSE1;0
clock_sweep APU_PULSE2;1
; Half-speed interrupts (120Hz) -- clock twice in each handler
;:half_frame
;:quarter_frame
; jsr half_frame_clock
; jsr quarter_frame_clock
; jsr quarter_frame_clock
; quarter frame updates run every APU frame
:quarter_frame
; Quarter-speed interrupts (60Hz) -- clock four times in each handler
;:half_frame
;:quarter_frame
; jsr half_frame_clock
; jsr quarter_frame_clock
; jsr quarter_frame_clock
; jsr half_frame_clock
; jsr quarter_frame_clock
; jsr quarter_frame_clock
; clock the envelopes and triangle linear counter
clock_linear_counter APU_TRIANGLE
clock_envelope APU_PULSE1
clock_envelope APU_PULSE2
clock_envelope APU_NOISE
:no_frame
; Apply any changes to the DOC registers
jsr access_doc_registers
; Set the parameters for the first square wave channel.
@ -779,7 +802,7 @@ interrupt_handler = *
:high_pitch pla
sta sound_data
:no_frame
:not_timer
ldal show_border
beq :no_show2