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First sounds from emulated APU
This commit is contained in:
Lucas Scharenbroich
parent
4f2c2aac0b
commit
1035af010d
206
demos/smb/apu.s
206
demos/smb/apu.s
@ -36,7 +36,7 @@ APUStartUp
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pea $c000
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pld
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jsr copy_instruments_to_doc
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; jsr setup_doc_registers
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jsr setup_doc_registers
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jsr setup_interrupt
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pld
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cli
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@ -218,11 +218,32 @@ setup_doc_registers
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jsr access_doc_registers
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ldx #pulse1_sound_settings
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jsr copy_register_config
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ldx #pulse2_sound_settings
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jsr copy_register_config
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ldx #triangle_sound_settings
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jsr copy_register_config
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rep #$20
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mx %00
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rts
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copy_register_config
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ldy #0
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:loop lda: 0,x ; Set DOC registers for the NES channels
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sta sound_address
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inx
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lda: 0,x
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sta sound_data
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inx
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iny
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cpy #6 ; 6 pairs to describe this oscillator
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bne :loop
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rts
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;--------------------------
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setup_interrupt = *
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@ -246,14 +267,14 @@ setup_interrupt = *
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jsr access_doc_registers
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ldy #0
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]loop lda timer_sound_settings,y ; Set DOC registers for the interrupt oscillator
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:loop lda timer_sound_settings,y ; Set DOC registers for the interrupt oscillator
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sta sound_address
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iny
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lda timer_sound_settings,y
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sta sound_data
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iny
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cpy #7*2
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bne ]loop
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bne :loop
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rep #$20
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mx %00
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@ -274,11 +295,11 @@ timer_sound_settings = * ; set up oscillator 30 for i
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pulse1_oscillator = 0
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pulse2_oscillator = 2
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triangle_oscillator = 4
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default_freq = 16384
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default_freq = 5000
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pulse1_sound_settings = *
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dfb $00+pulse1_oscillator,default_freq ; frequency low register
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dfb $20+pulse1_oscillator,default_freq/256 ; frequency high register
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dfb $40+pulse1_oscillator,0 ; volume register, volume = 0
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dfb $40+pulse1_oscillator,128 ; volume register, volume = 0
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dfb $80+pulse1_oscillator,3 ; wavetable pointer register, point to $0300 by default (50% duty cycle)
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dfb $c0+pulse1_oscillator,0 ; wavetable size register, 256 byte length
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dfb $a0+pulse1_oscillator,0 ; mode register, set to free run
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@ -286,7 +307,7 @@ pulse1_sound_settings = *
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pulse2_sound_settings = *
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dfb $00+pulse2_oscillator,default_freq ; frequency low register
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dfb $20+pulse2_oscillator,default_freq/256 ; frequency high register
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dfb $40+pulse2_oscillator,0 ; volume register, volume = 0
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dfb $40+pulse2_oscillator,120 ; volume register, volume = 0
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dfb $80+pulse2_oscillator,3 ; wavetable pointer register, point to $0300 by default (50% duty cycle)
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dfb $c0+pulse2_oscillator,0 ; wavetable size register, 256 byte length
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dfb $a0+pulse2_oscillator,0 ; mode register, set to free run
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@ -321,84 +342,66 @@ interrupt_handler = *
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lda #$c000
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tcd
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sep #$20
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mx %10
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sep #$30
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mx %11
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jsr access_doc_registers
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ldal osc_interrupt ; which oscillator generated the interrupt?
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interrupt_handler_loop
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and #%00111110
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lsr
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cmp #interrupt_oscillator
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bne :not_timer ; Only service timer interrupts
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beq *+5
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brl :not_timer ; Only service timer interrupts
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; Set the parameters for the first square wave channel
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lda APU_PULSE1_REG1 ; Get the cycle duty bits
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rol
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rol
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rol
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and #$03
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tax
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lda #$80+pulse1_oscillator
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sta sound_address
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lda duty_cycle_page,x
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sta sound_data
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lda APU_PULSE1_REG1 ; Get the cycle duty bits
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jsr set_pulse_duty_cycle
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lda APU_PULSE1_REG1 ; Get the volume
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and #$0F
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asl
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asl
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asl
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asl
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tax
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lda #$40+pulse1_oscillator
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sta sound_address
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txa
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sta sound_data
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lda APU_PULSE1_REG1
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jsr set_pulse_volume
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rep #$30
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mx %00
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lda APU_PULSE1_REG3
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and #$07FF ; Load the timer value (11-bits); freq = 1.79MHz / (16 * (t - 1)) = 111860Hz / (t-1)
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dec
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lsr ; Divide top and bottom by 2 -- 55930 / ((t - 1)/2)
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sta divisor
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lda #55930
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sta dividend
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jsr get_pulse_freq ; return freq in 16-bic accumulator
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sep #$30
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lda #0
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ldx #10 ; 10 bits of division
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asl dividend
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:dl1 rol
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cmp divisor
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bcc :dl2
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sbc divisor
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:dl2 rol dividend
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dex
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bne :dl1
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lda dividend
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and #$3FF ; This is the NES APU frequence in hertz
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sta dividend
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asl
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asl
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adc dividend ; multiple by 5 to get the approx DOC value (0.2Hz per)
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sta dividend
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sep #$20
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mx %10
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lda #$00+pulse1_oscillator
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sta sound_address
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lda dividend
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ldx #$00+pulse1_oscillator
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stx sound_address
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sta sound_data
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lda #$20+pulse1_oscillator
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ldx #$20+pulse1_oscillator
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stx sound_address
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xba
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sta sound_data
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; Now do the second square wave
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lda #$80+pulse2_oscillator
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sta sound_address
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lda dividend+1
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lda APU_PULSE2_REG1 ; Get the cycle duty bits
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jsr set_pulse_duty_cycle
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lda #$40+pulse2_oscillator
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sta sound_address
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lda APU_PULSE2_REG1
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jsr set_pulse_volume
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rep #$30
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lda APU_PULSE2_REG3
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jsr get_pulse_freq ; return freq in 16-bic accumulator
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sep #$30
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ldx #$00+pulse2_oscillator
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stx sound_address
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sta sound_data
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ldx #$20+pulse2_oscillator
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stx sound_address
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xba
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sta sound_data
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; lda border_color
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@ -414,6 +417,67 @@ interrupt_handler_loop
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clc
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rtl
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set_pulse_duty_cycle
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mx %11
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rol
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rol
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rol
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and #$03
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tax
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lda duty_cycle_page,x
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sta sound_data
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rts
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set_pulse_volume
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and #$0F
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asl
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asl
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asl
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asl
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sta sound_data
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rts
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get_pulse_freq
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mx %00
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and #$07FF ; Load the timer value (11-bits); freq = 1.79MHz / (16 * (t - 1)) = 111860Hz / (t-1)
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dec
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lsr ; Divide top and bottom by 2 -- 55930 / ((t - 1)/2)
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sta divisor
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lda #55930 ; $DA7A
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sta dividend
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lda #0
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ldx #16 ; 16 bits of division
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asl dividend
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:dl1 rol
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cmp divisor
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bcc :dl2
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sbc divisor
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:dl2 rol dividend
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dex
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bne :dl1
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lda dividend
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sta dividend
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asl
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; asl
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asl
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asl
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adc dividend ; multiple by 5 to get the approx DOC value (0.2Hz per)
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; sta dividend
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rts
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turn_off_interrupts
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php
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sep #$20
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lda #$a0+interrupt_oscillator
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sta sound_address
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lda #0
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sta sound_data
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plp
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rts
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duty_cycle_page dfb $01,$02,$03,$04 ; Page of DOC RAM that holds the different duty cycle wavforms
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border_color dw 0
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dividend dw 0
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@ -532,13 +596,13 @@ APU_STATUS_WRITE ENT
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:pulse2_end
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; Triangle is OSC 4
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bit #$03
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beq :triangle_off
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_SetDOCReg #$40+triangle_oscillator;#128
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bra :triangle_end
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:triangle_off
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_SetDOCReg #$40+triangle_oscillator;#0
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:triangle_end
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; bit #$03
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; beq :triangle_off
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; _SetDOCReg #$40+triangle_oscillator;#128
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; bra :triangle_end
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;:triangle_off
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; _SetDOCReg #$40+triangle_oscillator;#0
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;:triangle_end
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pla
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rtl
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@ -681,35 +681,74 @@ debug_values
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jsr DrawWord
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ldx #8*160
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ldy #$FFFF
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ldy #$EEEE
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lda APU_PULSE1_REG1
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jsr DrawWord
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ldx #16*160
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ldy #$FFFF
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ldy #$EEEE
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lda APU_PULSE1_REG3
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jsr DrawWord
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ldx #24*160
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ldy #$FFFF
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ldy #$DDDD
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lda APU_PULSE2_REG1
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jsr DrawWord
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ldx #32*160
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ldy #$FFFF
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ldy #$DDDD
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lda APU_PULSE2_REG3
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jsr DrawWord
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ldx #40*160
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ldy #$FFFF
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ldy #$BBBB
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lda APU_TRIANGLE_REG1
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jsr DrawWord
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ldx #48*160
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ldy #$FFFF
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ldy #$BBBB
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lda APU_TRIANGLE_REG3
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jsr DrawWord
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; Fetch the ensoniq parameters
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sep #$20
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ldal irq_volume
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stal $e1c000+sound_control ; access registers
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lda #$80+pulse1_oscillator ; oscillator address
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stal $e1c000+sound_address
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ldal $e1c000+sound_data
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ldal $e1c000+sound_data
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xba
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lda #$40+pulse1_oscillator ; oscillator volume
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stal $e1c000+sound_address
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ldal $e1c000+sound_data
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ldal $e1c000+sound_data
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rep #$30
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ldx #{8*160}+{160-16}
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ldy #$EEEE
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jsr DrawWord
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sep #$20
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lda #$20+pulse1_oscillator ; oscillator freq high
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stal $e1c000+sound_address
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ldal $e1c000+sound_data
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ldal $e1c000+sound_data
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xba
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lda #$00+pulse1_oscillator ; oscillator freq low
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stal $e1c000+sound_address
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ldal $e1c000+sound_data
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ldal $e1c000+sound_data
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rep #$30
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ldx #{16*160}+{160-16}
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ldy #$EEEE
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jsr DrawWord
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sep #$30
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plx
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ply
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