mirror of
https://github.com/lscharen/iigs-game-engine.git
synced 2024-11-28 20:49:38 +00:00
Optimization to avoid recalculating DOC frequencies when APU value does not change
This commit is contained in:
Lucas Scharenbroich
parent
bdb4006e22
commit
a1261e8339
@ -587,6 +587,9 @@ interrupt_handler = *
|
||||
cmp #8
|
||||
bcc :mute_pulse1
|
||||
|
||||
cmp _apu_pulse1_last_period ; it's expensive to recalc frequencies, so avoid it when possible
|
||||
beq :freq_end_pulse1
|
||||
sta _apu_pulse1_last_period
|
||||
jsr get_pulse_freq ; return freq in 16-bit accumulator
|
||||
sep #$30
|
||||
ldx #$00+pulse1_oscillator
|
||||
@ -596,6 +599,7 @@ interrupt_handler = *
|
||||
stx sound_address
|
||||
xba
|
||||
sta sound_data
|
||||
:freq_end_pulse1 sep #$30 ; redundent, but avoids extra branches
|
||||
|
||||
lda #$80+pulse1_oscillator
|
||||
sta sound_address
|
||||
@ -627,6 +631,9 @@ interrupt_handler = *
|
||||
cmp #8
|
||||
bcc :mute_pulse2
|
||||
|
||||
cmp _apu_pulse2_last_period
|
||||
beq :freq_end_pulse2
|
||||
sta _apu_pulse2_last_period
|
||||
jsr get_pulse_freq ; return freq in 16-bic accumulator
|
||||
sep #$30
|
||||
ldx #$00+pulse2_oscillator
|
||||
@ -636,6 +643,7 @@ interrupt_handler = *
|
||||
stx sound_address
|
||||
xba
|
||||
sta sound_data
|
||||
:freq_end_pulse2 sep #$30
|
||||
|
||||
lda #$80+pulse2_oscillator
|
||||
sta sound_address
|
||||
@ -676,6 +684,9 @@ interrupt_handler = *
|
||||
; Man's stage. At the expense of accuracy, these can be eliminated in an emulator e.g. by halting the
|
||||
; triangle channel when an ultrasonic frequency is set (a timer value less than 2).
|
||||
|
||||
cmp _apu_triangle_last_period
|
||||
beq :freq_end_triangle
|
||||
sta _apu_triangle_last_period
|
||||
jsr get_pulse_freq ; return freq in 16-bic accumulator
|
||||
lsr
|
||||
sep #$30
|
||||
@ -686,6 +697,7 @@ interrupt_handler = *
|
||||
stx sound_address
|
||||
xba
|
||||
sta sound_data
|
||||
:freq_end_triangle sep #$30
|
||||
|
||||
lda #$40+triangle_oscillator
|
||||
sta sound_address
|
||||
@ -701,23 +713,17 @@ interrupt_handler = *
|
||||
|
||||
; Now the noise channel. It's mixer volume output is ~half of the pulse channels
|
||||
|
||||
lda #$40+noise_oscillator
|
||||
sta sound_address
|
||||
|
||||
lda APU_NOISE_LENGTH_COUNTER ; If the length counter is zero, no output
|
||||
beq :set_volume_noise
|
||||
lda APU_NOISE_REG1
|
||||
bit #NOISE_CONST_VOL_FLAG ; Check the constant volume bit
|
||||
bne :set_volume_noise
|
||||
lda APU_NOISE_ENVELOPE
|
||||
:set_volume_noise
|
||||
jsr set_pulse_volume
|
||||
lda APU_NOISE_LENGTH_COUNTER ; If the length counter is zero, no output
|
||||
beq :mute_noise
|
||||
|
||||
rep #$30
|
||||
lda APU_NOISE_CURRENT_PERIOD
|
||||
|
||||
cmp _apu_noise_last_period ; it's expensive to recalc frequencies, so avoid it when possible
|
||||
beq :freq_end_noise
|
||||
sta _apu_noise_last_period
|
||||
jsr get_pulse_freq ; return freq in 16-bic accumulator
|
||||
sep #$30
|
||||
|
||||
ldx #$00+noise_oscillator
|
||||
stx sound_address
|
||||
sta sound_data
|
||||
@ -725,9 +731,23 @@ interrupt_handler = *
|
||||
stx sound_address
|
||||
xba
|
||||
sta sound_data
|
||||
:freq_end_noise sep #$30
|
||||
|
||||
lda #$40+noise_oscillator
|
||||
sta sound_address
|
||||
lda APU_NOISE_REG1
|
||||
bit #NOISE_CONST_VOL_FLAG ; Check the constant volume bit
|
||||
bne :set_volume_noise
|
||||
lda APU_NOISE_ENVELOPE
|
||||
bra :set_volume_noise
|
||||
:mute_noise
|
||||
sep #$30
|
||||
lda #$40+noise_oscillator
|
||||
sta sound_address
|
||||
lda #0
|
||||
:set_volume_noise jsr set_pulse_volume
|
||||
|
||||
:not_timer
|
||||
sep #$30
|
||||
lda #0
|
||||
jsr setborder
|
||||
|
||||
@ -817,49 +837,11 @@ turn_off_interrupts
|
||||
|
||||
apu_frame_counter dw 0 ; frame counter, clocked at 240Hz from the interrupt handler
|
||||
|
||||
; Internal APU register offsets
|
||||
;length_counter_halt equ 0
|
||||
;length_counter equ 1
|
||||
;constant_volume_flag equ 2
|
||||
;volume equ 3
|
||||
;current_period equ 4
|
||||
;target_period equ 6
|
||||
|
||||
; Internal APU registers for channel 1
|
||||
;apu_pulse1 ds 8
|
||||
;apu_pulse2 ds 8
|
||||
|
||||
;apu_pulse1_length_counter dfb 0
|
||||
;apu_pulse1_decay_level dfb 0
|
||||
;apu_pulse1_current_period dw 0
|
||||
|
||||
;apu_pulse2_length_counter dfb 0
|
||||
;apu_pulse2_decay_level dfb 0
|
||||
;apu_pulse2_current_period dw 0
|
||||
|
||||
duty_cycle_page dfb $01,$02,$03,$04 ; Page of DOC RAM that holds the different duty cycle wavforms
|
||||
border_color dw 0
|
||||
dividend dw 0
|
||||
dividend dw 0 ; Used when converting from NES APU values to DOC values
|
||||
divisor dw 0
|
||||
|
||||
last_phase1_duty_cycle dfb $ff
|
||||
last_phase2_duty_cycle dfb $ff
|
||||
; 8-bit mode
|
||||
; A = register number
|
||||
; X = register value
|
||||
mx %00
|
||||
SetDOCReg
|
||||
stal $E0C03E
|
||||
txa
|
||||
stal $E0C03D
|
||||
rts
|
||||
|
||||
_SetDOCReg mac
|
||||
lda ]1 ; Select the oscillator enable registers
|
||||
ldx ]2
|
||||
jsr SetDOCReg
|
||||
<<<
|
||||
|
||||
; Pulse Channel 1
|
||||
APU_PULSE1
|
||||
APU_PULSE1_REG1 ds 1 ; DDLC NNNN - Duty, length counter halt, constant volume/evelope, envelope period/volume
|
||||
@ -877,7 +859,7 @@ APU_PULSE1_START_FLAG dfb 0
|
||||
APU_PULSE1_ENVELOPE_DIVIDER dfb 0
|
||||
APU_PULSE1_ENVELOPE dfb 0
|
||||
|
||||
_apu_pulse1_last_period dw 0 ; optimization
|
||||
_apu_pulse1_last_period dw $FFFF ; optimization
|
||||
|
||||
|
||||
APU_PULSE2
|
||||
@ -896,7 +878,7 @@ APU_PULSE2_START_FLAG dfb 0
|
||||
APU_PULSE2_ENVELOPE_DIVIDER dfb 0
|
||||
APU_PULSE2_ENVELOPE dfb 0
|
||||
|
||||
_apu_pulse2_last_period dw 0 ; optimization
|
||||
_apu_pulse2_last_period dw $FFFF ; optimization
|
||||
|
||||
|
||||
APU_TRIANGLE
|
||||
@ -910,6 +892,8 @@ APU_TRIANGLE_CURRENT_PERIOD dw 0
|
||||
APU_TRIANGLE_START_FLAG dfb 0
|
||||
APU_TRIANGLE_LINEAR_COUNTER dfb 0
|
||||
|
||||
_apu_triangle_last_period dw $FFFF ; optimization
|
||||
|
||||
|
||||
APU_NOISE
|
||||
APU_NOISE_REG1 ds 1 ; --LC NNNN - length counter halt, constant volume/evelope, envelope period/volume
|
||||
@ -927,6 +911,9 @@ APU_NOISE_START_FLAG dfb 0
|
||||
APU_NOISE_ENVELOPE_DIVIDER dfb 0
|
||||
APU_NOISE_ENVELOPE dfb 0
|
||||
|
||||
_apu_noise_last_period dw $FFFF ; optimization
|
||||
|
||||
|
||||
APU_STATUS ds 1
|
||||
|
||||
mx %11
|
||||
|
||||
Loading…
Reference in New Issue
Block a user