;
-; Startup code for cc65 (PCEngine version)
+; Start-up code for cc65 (PC-Engine version)
;
-; by Groepaz/Hitmen <groepaz@gmx.net>
+; by Groepaz/Hitmen <groepaz@gmx.net>,
; based on code by Ullrich von Bassewitz <uz@cc65.org>
;
-; This must be the *first* file on the linker command line
+; 2018-02-24, Greg King
;
- .export _exit
- .import initlib, donelib
- .import push0, _main, zerobss
- .import initheap
- .import tmp1,tmp2,tmp3
+ .export _exit
+ .export __STARTUP__ : absolute = 1 ; Mark as start-up
- .import __RAM_START__, __RAM_SIZE__ ; Linker generated
-;; .import __SRAM_START__, __SRAM_SIZE__ ; Linker generated
- .import __ROM0_START__, __ROM0_SIZE__ ; Linker generated
- .import __ROM_START__, __ROM_SIZE__ ; Linker generated
- .import __STARTUP_LOAD__,__STARTUP_RUN__, __STARTUP_SIZE__ ; Linker generated
- .import __CODE_LOAD__,__CODE_RUN__, __CODE_SIZE__ ; Linker generated
- .import __RODATA_LOAD__,__RODATA_RUN__, __RODATA_SIZE__ ; Linker generated
- .import __DATA_LOAD__,__DATA_RUN__, __DATA_SIZE__ ; Linker generated
- .import __BSS_SIZE__
+ .import initlib, donelib
+ .import push0, _main
+ .import IRQStub, __nmi
+ .importzp sp
- .include "pcengine.inc"
+ ; Linker-generated
+ .import __CARTSIZE__
+ .import __DATA_LOAD__, __DATA_RUN__, __DATA_SIZE__
+ .import __BSS_RUN__, __BSS_SIZE__
+ .import __MAIN_START__, __MAIN_SIZE__, __STACKSIZE__
- .importzp sp
- .importzp ptr1,ptr2
+ .include "pce.inc"
+ .include "extzp.inc"
; ------------------------------------------------------------------------
-; Create an empty LOWCODE segment to avoid linker warnings
-
-.segment "LOWCODE"
-
-; ------------------------------------------------------------------------
-; Place the startup code in a special segment.
-
-.segment "STARTUP"
-
-start:
-
-; setup the CPU and System-IRQ
-
- ; Initialize CPU
-
- sei
- nop
- csh
- nop
- cld
- nop
-
- ; Setup stack and memory mapping
- ldx #$FF ; Stack top ($21FF)
- txs
- txa
- tam #0 ; 0000-1FFF = Hardware page
-
- lda #$F8
- tam #1 ; 2000-3FFF = Work RAM
-
- lda #$F7
- tam #2 ; 4000-5FFF = Save RAM
-
- lda #1
- tam #3 ; 6000-7FFF Page 2
- lda #2
- tam #4 ; 8000-9FFF Page 3
- lda #3
- tam #5 ; A000-BFFF Page 4
- lda #4
- tam #6 ; C000-DFFF Page 5
-
- ; Initialize hardware
- stz TIMER_COUNT ; Timer off
- lda #$07
- sta IRQ_MASK ; Interrupts off
- stz IRQ_STATUS ; Acknowledge timer
-
- ; Clear work RAM
- stz <$00
- tii $2000, $2001, $1FFF
-
- ;; i dont know why the heck this one doesnt
- ;; work when called from a constructor :/
- .import vdc_init
- jsr vdc_init
-;; jsr joy_init
-
- ; Turn on background and VD interrupt/IRQ1
- lda #$05
- sta IRQ_MASK ; IRQ1=on
- cli
-
-; Clear the BSS data
-
- jsr zerobss
-
-; Copy the .data segment to RAM
-
- lda #<(__DATA_LOAD__)
- ;;lda #<(__ROM0_START__ + __STARTUP_SIZE__+ __CODE_SIZE__+ __RODATA_SIZE__)
- ;;lda #<(__ROM_START__ + __CODE_SIZE__+ __RODATA_SIZE__)
- sta ptr1
- lda #>(__DATA_LOAD__)
- ;;lda #>(__ROM_START__ + __CODE_SIZE__+ __RODATA_SIZE__)
- sta ptr1+1
- lda #<(__DATA_RUN__)
- ;;lda #<(__SRAM_START__)
- sta ptr2
- lda #>(__DATA_RUN__)
- ;;lda #>(__SRAM_START__)
- sta ptr2+1
-
- ldx #>(__DATA_SIZE__)
-
-@l2:
- beq @s1 ; no more full pages
-
- ; copy one page
- ldy #0
-@l1:
- lda (ptr1),y
- sta (ptr2),y
- iny
- bne @l1
-
- inc ptr1+1
- inc ptr2+1
-
- dex
- bne @l2
-
- ; copy remaining bytes
-@s1:
-
- ; copy one page
- ldy #0
-@l3:
- lda (ptr1),y
- sta (ptr2),y
- iny
- cpy #<(__DATA_SIZE__)
- bne @l3
-
-; setup the stack
-
-; lda #<(__RAM_START__ + __DATA_SIZE__ + __BSS_SIZE__)
- lda #<(__RAM_START__+__RAM_SIZE__)
- sta sp
-; lda #>(__RAM_START__ + __DATA_SIZE__ + __BSS_SIZE__)
- lda #>(__RAM_START__+__RAM_SIZE__)
- sta sp+1 ; Set argument stack ptr
-
-; Init the Heap
- jsr initheap
-
-;jmp *
-
-; Call module constructors
-
- jsr initlib
-; .import initconio
-; jsr initconio
-; Pass an empty command line
-
-
-;jmp *
-
- jsr push0 ; argc
- jsr push0 ; argv
-go:
- ldy #4 ; Argument size
- jsr _main ; call the users code
-
-; Call module destructors. This is also the _exit entry.
-
-_exit:
- jsr donelib ; Run module destructors
-
-; reset the PCEngine
-
- jmp start
-
-; ------------------------------------------------------------------------
-; System V-Blank Interupt
-; ------------------------------------------------------------------------
-
-_irq1:
- pha
- phx
- phy
-
-
- inc _tickcount
- bne @s
- inc _tickcount+1
-@s:
-
- ; Acknowlege interrupt
- ldaio VDC_CTRL
-
- ply
- plx
- pla
- rti
-_irq2:
- rti
-_nmi:
- rti
-_timer:
- stz IRQ_STATUS
- rti
-
- .export initmainargs
+; Place the start-up code in a special segment.
+
+.segment "STARTUP"
+
+ ; Initialize the CPU.
+start: sei
+ nop
+ csh ; Set high-speed CPU mode
+ nop
+
+ ; Set up the stack and the memory mapping.
+ ldx #$FF ; Stack top ($21FF)
+ txs
+
+ ; At power-on, most MPRs have random values; so, initiate them.
+ lda #$FF
+ tam #%00000001 ; $0000-$1FFF = Hardware bank
+ lda #$F8
+ tam #%00000010 ; $2000-$3FFF = Work RAM
+ ;lda #$F7
+ ;tam #%00000100 ; $4000-$47FF = 2K Battery-backed RAM
+ ;lda #4
+ ;tam #%00001000 ; $6000-$7FFF
+
+ lda #$01
+ ldx #>$8000
+ cpx #>__CARTSIZE__
+ bcc @L1 ;(blt)
+ tam #%00010000 ; $8000-$9FFF = ROM bank 1 (32K block of ROM)
+ inc a
+ tam #%00100000 ; $A000-$BFFF = ROM bank 2
+ inc a
+@L1: tam #%01000000 ; $C000-$DFFF = ROM bank 3 (32K) or 1 (16K)
+ ;lda #$00 ; (The reset default)
+ ;tam #%10000000 ; $E000-$FFFF Hucard/Syscard bank 0
+
+ ; Initialize the hardware.
+ stz TIMER_CTRL ; Timer off
+ lda #%00000111
+ sta IRQ_MASK ; Interrupts off
+
+ ; FIXME; I don't know why the heck this one doesn't work when called from a constructor. -Groepaz :-/
+.if 0 ; It now seems to work (at least, in Mednafen). -Greg King
+ .import vdc_init
+ jsr vdc_init
+.endif
+
+ ; Allow interrupts from the VDC.
+ lda #%00000101
+ sta IRQ_MASK ; IRQ1 = on
+
+ ; Copy the .data segment to RAM
+ tii __DATA_LOAD__, __DATA_RUN__, __DATA_SIZE__
+
+ ; Clear the .bss segment
+ stz __BSS_RUN__
+ tii __BSS_RUN__, __BSS_RUN__ + 1, __BSS_SIZE__ - 1
+
+ ; Set up the stack
+ lda #<(__MAIN_START__ + __MAIN_SIZE__ + __STACKSIZE__)
+ ldx #>(__MAIN_START__ + __MAIN_SIZE__ + __STACKSIZE__)
+ sta sp
+ stx sp+1
+
+ ; Call the module constructors.
+ jsr initlib
+
+ stz IRQ_STATUS ; Clear IRQs
+ cli ; Allow IRQ only after constructors have run
+
+ ; Pass an empty command line
+ jsr push0 ; argc
+ jsr push0 ; argv
+
+ ldy #4 ; Argument size
+ jsr _main ; Call the user's code
+
+ ; Call the module destructors. This is also the exit() entry.
+_exit: jsr donelib
+
+ ; Reset the PCEngine (start over).
+ jmp start
+
+ .export initmainargs
initmainargs:
- rts
+ rts
; ------------------------------------------------------------------------
; hardware vectors
; ------------------------------------------------------------------------
- .segment "VECTORS"
- ;;.org $fff6
-
- .word _irq2 ; $fff6 IRQ2 (External IRQ, BRK)
- .word _irq1 ; $fff8 IRQ1 (VDC)
- .word _timer ; $fffa Timer
- .word _nmi ; $fffc NMI
- .word start ; $fffe reset
-
-
+.segment "VECTORS"
+ .word IRQStub ; $FFF6 IRQ2 (External IRQ, BRK)
+ .word IRQStub ; $FFF8 IRQ1 (VDC)
+ .word IRQStub ; $FFFA Timer
+ .word __nmi ; $FFFC NMI
+ .word start ; $FFFE reset
projects / cc65 / blobdiff