sd2snes/snes/spcplay.a65
2013-10-06 14:52:40 +01:00

677 lines
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#include "memmap.i65"
; SPC Player
; SPC700 transfer and IO routines by Shay Green <gblargg@gmail.com>
spcplayer:
php
sep #$30 : .as : .xs
ldx #$0a ; Check if SPC header is present
-
lda @SPC_HEADER,x
cmp @text_spcid,x
beq +
jmp spc_exit
+
dey
bne -
rep #$10 : .xl ; Now draw lots of stuff
stz bar_wl
dec bar_wl
stz bar_xl
dec bar_xl
stz bar_yl
dec bar_yl
jsr backup_screen
lda #^text_spcplay ; Loading window
sta window_tbank
ldx #!text_spcplay
stx window_taddr
lda @spcplay_win_x
sta window_x
lda @spcplay_win_y
sta window_y
lda @spcplay_win_w
sta window_w
lda @spcplay_win_h
sta window_h
jsr draw_window
lda #^text_spcload ; Loading text
ldx #!text_spcload
sta print_bank
stx print_src
stz print_pal
lda #29
sta print_count
lda #17
sta print_y
lda #17
sta print_x
jsr hiprint
stz isr_done
-
lda isr_done ; Wait until text is being printed...
beq -
jsr spc700_load ; Load SPC into SPC700
lda #^text_spcplay
sta window_tbank
ldx #!text_spcplay
stx window_taddr
lda @spcstart_win_x
sta window_x
lda @spcstart_win_y
sta window_y
lda @spcstart_win_w
sta window_w
lda @spcstart_win_h
sta window_h
jsr draw_window
lda #^text_spcstarta
ldx #!text_spcstarta
sta print_bank
stx print_src
lda #$01
sta print_pal
lda #30
sta print_count
lda #15
sta print_y
lda #17
sta print_x
jsr hiprint
lda #^text_spcstartb
ldx #!text_spcstartb
sta print_bank
stx print_src
lda #$01
sta print_pal
lda #07
sta print_count
lda #17
sta print_y
lda #12
sta print_x
jsr hiprint
lda #$fe
ldx #$004e
sta print_bank
stx print_src
stz print_pal
lda #32
sta print_count
lda #17
sta print_y
lda #20
sta print_x
jsr hiprint
lda #^text_spcstartc
ldx #!text_spcstartc
sta print_bank
stx print_src
lda #$01
sta print_pal
lda #07
sta print_count
lda #18
sta print_y
lda #12
sta print_x
jsr hiprint
lda #$fe
ldx #$002e
sta print_bank
stx print_src
stz print_pal
lda #32
sta print_count
lda #18
sta print_y
lda #20
sta print_x
jsr hiprint
lda #^text_spcstartd
ldx #!text_spcstartd
sta print_bank
stx print_src
lda #$01
sta print_pal
lda #07
sta print_count
lda #19
sta print_y
lda #12
sta print_x
jsr hiprint
lda #$fe
ldx #$00b0
sta longptr+2
sta print_bank
stx longptr
ldy #$00
lda [longptr], y
cmp #$41
bpl +
inx
+ stx print_src
stz print_pal
lda #32
sta print_count
lda #19
sta print_y
lda #20
sta print_x
jsr hiprint
spc_playloop:
lda isr_done ; SPC player loop
lsr
bcc spc_playloop
jsr printtime
stz isr_done
jsr read_pad
lda #$80
and pad1trig+1
bne spc_key_b
bra spc_playloop
spc_key_b:
rep #$20 : .al
tsc
sta saved_sp ; Save SP for later re-entry
lda #$fa50 ; Write reset signature
sta @warm_signature
sep #$20 : .as
sei ; Blank screen & issue CMD_RESET command to Microcontroller...
stz $2100 ; ...this is required, because there is no other way to stop S-SMP & S-DSP
lda #CMD_RESET
sta @MCU_CMD
-
bra - ; At this point, the SNES waits for an external reset from the Microcontroller
spc_exit: ; Return from player in case of wrong SPC file data
plp
rts
;---------------------------------------
spc700_load:
php
sep #$20 : .as
rep #$10 : .xl
sei ; Disable NMI & IRQ
stz $4200 ; The SPC player code is really timing sensitive ;)
jsr upload_dsp_regs ; Upload S-DSP registers
jsr upload_high_ram ; Upload 63.5K of SPC700 ram
jsr upload_low_ram ; Upload rest of ram
jsr restore_final ; Restore SPC700 state & start execution
lda #$81 ; VBlank NMI + Auto Joypad Read
sta $4200 ; enable V-BLANK NMI
cli
plp
rts
;---------------------------------------
; Uploads DSP registers and some other setup code
upload_dsp_regs:
; ---- Begin upload
ldy #$0002
jsr spc_begin_upload
; ---- Upload loader
ldx #$0000
-
lda @loader,x
jsr spc_upload_byte
inx
cpy #31 ; size of loader
bne -
; ---- Upload SP, PC & PSW
lda @SPC_HEADER+43
jsr spc_upload_byte
lda @SPC_HEADER+38
jsr spc_upload_byte
lda @SPC_HEADER+37
jsr spc_upload_byte
lda @SPC_HEADER+42
jsr spc_upload_byte
; ---- Upload DSP registers
ldx #$0000
-
; initialize FLG and KON ($6c/$4c) to avoid artifacts
cpx #$4C
bne +
lda #$00
bra upload_skip_load
+
cpx #$6C
bne +
lda #$E0
bra upload_skip_load
+
lda @SPC_DSP_REGS,x
upload_skip_load
jsr spc_upload_byte
inx
cpx #128
bne -
; --- Upload fixed values for $F1-$F3
ldy #$00F1
jsr spc_next_upload
lda #$80 ; stop timers
jsr spc_upload_byte
lda #$6c ; get dspaddr set for later
jsr spc_upload_byte
lda #$60
jsr spc_upload_byte
; ---- Upload $f8-$1ff
ldy #$00F8
jsr spc_next_upload
ldx #$00F8
-
lda @SPC_DATA,x
jsr spc_upload_byte
inx
cpx #$200
bne -
; ---- Execute loader
ldy #$0002
jsr spc_execute
rts
;---------------------------------------
upload_high_ram:
ldy #$0002
jsr spc_begin_upload
; ---- Upload transfer routine
ldx #$0000
-
lda @transfer,x
jsr spc_upload_byte
inx
cpy #43 ; size of transfer routine
bne -
ldx #$023f ; prepare transfer address
; ---- Execute transfer routine
ldy #$0002
sty APUIO2
stz APUIO1
lda APUIO0
inc
inc
sta APUIO0
; Wait for acknowledgement
-
cmp APUIO0
bne -
; ---- Burst transfer of 63.5K using custom routine
outer_transfer_loop:
ldy #$003f ; 3
inner_transfer_loop:
lda @SPC_DATA,x ; 5 |
sta APUIO0 ; 4 |
lda @SPC_DATA+$40,x ; 5 |
sta APUIO1 ; 4 |
lda @SPC_DATA+$80,x ; 5 |
sta APUIO2 ; 4 |
lda @SPC_DATA+$C0,x ; 5 |
sta APUIO3 ; 4 |
tya ; 2 >> 38 cycles
-
cmp APUIO3 ; 4 |
bne - ; 3 |
dex ; 2 |
dey ; 2 |
bpl inner_transfer_loop ; 3 >> 14 cycles
rep #$21 : .al ; 3 |
txa ; 2 |
adc #$140 ; 3 |
tax ; 2 |
sep #$20 : .as ; 3 |
cpx #$003f ; 3 |
bne outer_transfer_loop ; 3 >> 19 cycles
rts
;---------------------------------------
upload_low_ram:
; ---- Upload $0002-$00EF using IPL
ldy #$0002
jsr spc_begin_upload
ldx #$0002
-
lda @SPC_DATA,x
jsr spc_upload_byte
inx
cpx #$00F0
bne -
rts
;---------------------------------------
; Executes final restoration code
restore_final:
jsr start_exec_io ; prepare execution from I/O registers
stz $420d ; SPC700 I/O code requires SLOW timing
; ---- Restore first two bytes of RAM
lda @SPC_DATA
xba
lda #$e8 ; MOV A,#@SPC_DATA
tax
jsr exec_instr
ldx #$00C4 ; MOV $00,A
jsr exec_instr
lda @SPC_DATA+1
xba
lda #$e8 ; MOV A,#@SPC_DATA+1
tax
jsr exec_instr
ldx #$01C4 ; MOV $01,A
jsr exec_instr
; ---- Restore SP
lda @SPC_HEADER+43
sec
sbc #3
xba
lda #$cd ; MOV X,#@SPC_HEADER+43
tax
jsr exec_instr
ldx #$bd ; MOV SP,X
jsr exec_instr
; ---- Restore X
lda @SPC_HEADER+40
xba
lda #$cd ; MOV X,#@SPC_HEADER+40
tax
jsr exec_instr
; ---- Restore Y
lda @SPC_HEADER+41
xba
lda #$8d ; MOV Y,#@SPC_HEADER+41
tax
jsr exec_instr
; ---- Restore DSP FLG register
lda @SPC_DSP_REGS+$6c
xba
lda #$e8 ; MOV A,#@SPC_DSP_REGS+$6c
tax
jsr exec_instr
ldx #$f3C4 ; MOV $f3,A -> $f2 has been set-up before by SPC700 loader
jsr exec_instr
; ---- wait a bit (the newer S-APU takes its time to ramp up the volume)
lda #$10
- pha
jsr waitblank
pla
dec
bne -
; ---- Restore DSP KON register
lda #$4C
xba
lda #$e8 ; MOV A,#$4c
tax
jsr exec_instr
ldx #$f2C4 ; MOV $f2,A
jsr exec_instr
lda @SPC_DSP_REGS+$4C
xba
lda #$e8 ; MOV A,#@SPC_DSP_REGS+$4c
tax
jsr exec_instr
ldx #$f3C4 ; MOV $f3,A
jsr exec_instr
; ---- Restore DSP register address
lda @SPC_DATA+$F2
xba
lda #$e8 ; MOV A,#@SPC_DATA+$F2
tax
jsr exec_instr
ldx #$f2C4 ; MOV dest,A
jsr exec_instr
; ---- Restore CONTROL register
lda @SPC_DATA+$F1
and #$CF ; don't clear input ports
xba
lda #$e8 ; MOV A,#@SPC_DATA+$F1
tax
jsr exec_instr
ldx #$f1C4 ; MOV $F1,A
jsr exec_instr
;---- Restore A
lda @SPC_HEADER+39
xba
lda #$e8 ; MOV A,#@SPC_HEADER+39
tax
jsr exec_instr
;---- Restore PSW and PC
ldx #$7F00 ; NOP; RTI
stx APUIO0
lda #$FC ; Patch loop to execute instruction just written
sta APUIO3
;---- restore IO ports $f4 - $f7
rep #$20 : .al
lda @SPC_DATA+$F4
tax
lda @SPC_DATA+$F6
sta APUIO2
stx APUIO0 ; last to avoid overwriting RETI before run
sep #$20 : .as
lda #$01
sta $420d ; restore FAST CPU operation
rts
;---------------------------------------
spc_begin_upload:
sty APUIO2 ; Set address
ldy #$BBAA ; Wait for SPC
-
cpy APUIO0
bne -
lda #$CC ; Send acknowledgement
sta APUIO1
sta APUIO0
- ; Wait for acknowledgement
cmp APUIO0
bne -
ldy #0 ; Initialize index
rts
;---------------------------------------
spc_upload_byte:
sta APUIO1
tya ; Signal it's ready
sta APUIO0
- ; Wait for acknowledgement
cmp APUIO0
bne -
iny
rts
;---------------------------------------
spc_next_upload:
sty APUIO2
; Send command
; Special case operation has been fully tested.
lda APUIO0
inc
inc
bne +
inc
+
sta APUIO1
sta APUIO0
; Wait for acknowledgement
-
cmp APUIO0
bne -
ldy #0
rts
;---------------------------------------
spc_execute:
sty APUIO2
stz APUIO1
lda APUIO0
inc
inc
sta APUIO0
; Wait for acknowledgement
-
cmp APUIO0
bne -
rts
;---------------------------------------
start_exec_io:
; Set execution address
ldx #$00F5
stx APUIO2
stz APUIO1 ; NOP
ldx #$FE2F ; BRA *-2
; Signal to SPC that we're ready
lda APUIO0
inc
inc
sta APUIO0
; Wait for acknowledgement
-
cmp APUIO0
bne -
; Quickly write branch
stx APUIO2
rts
;---------------------------------------
exec_instr:
; Replace instruction
stx APUIO0
lda #$FC
sta APUIO3 ; 30
; SPC BRA loop takes 4 cycles, so it reads
; the branch offset every 4 SPC cycles (84 master).
; We must handle the case where it read just before
; the write above, and when it reads just after it.
; If it reads just after, we have at least 7 SPC
; cycles (147 master) to change restore the branch
; offset.
; 48 minimum, 90 maximum
ora #0
ora #0
ora #0
nop
nop
nop
; 66 delay, about the middle of the above limits
phd ;4
pld ;5
; Give plenty of extra time if single execution
; isn't needed, as this avoids such tight timing
; requirements.
; phd ;4
; pld ;5
; phd ;4
; pld ;5
; Patch loop to skip first two bytes
lda #$FE ; 16
sta APUIO3 ; 30
; 38 minimum (assuming 66 delay above)
phd ; 4
pld ; 5
; Give plenty of extra time if single execution
; isn't needed, as this avoids such tight timing
; requirements.
phd
pld
phd
pld
rts