; This must be the *first* file on the linker command line
;
- .export _exit
- .export __STARTUP__ : absolute = 1 ; Mark as startup
- .import initlib, donelib
- .import push0, _main, zerobss
- .import initheap
- .import tmp1,tmp2,tmp3
-
- .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__
-
- .include "pcengine.inc"
-
- .importzp sp
- .importzp ptr1,ptr2
+ .export _exit
+ .export __STARTUP__ : absolute = 1 ; Mark as startup
-; ------------------------------------------------------------------------
-; Create an empty LOWCODE segment to avoid linker warnings
+ .import initlib, donelib
+ .import push0, _main, zerobss
+ .import initheap
+ .import tmp1,tmp2,tmp3
+
+ ; Linker generated
+ .import __RAM_START__, __RAM_SIZE__
+ .import __ROM0_START__, __ROM0_SIZE__
+ .import __ROM_START__, __ROM_SIZE__
+ .import __STARTUP_LOAD__,__STARTUP_RUN__, __STARTUP_SIZE__
+ .import __CODE_LOAD__,__CODE_RUN__, __CODE_SIZE__
+ .import __RODATA_LOAD__,__RODATA_RUN__, __RODATA_SIZE__
+ .import __DATA_LOAD__,__DATA_RUN__, __DATA_SIZE__
+ .import __BSS_SIZE__
+
+ .include "pce.inc"
-.segment "LOWCODE"
+ .importzp sp
+ .importzp ptr1,ptr2
; ------------------------------------------------------------------------
; Place the startup code in a special segment.
-.segment "STARTUP"
+ .segment "STARTUP"
start:
-; setup the CPU and System-IRQ
+ ; setup the CPU and System-IRQ
; Initialize CPU
sei
nop
- csh ; set high speed CPU mode
+ csh ; set high speed CPU mode
nop
cld
nop
; Setup stack and memory mapping
- ldx #$FF ; Stack top ($21FF)
+ ldx #$FF ; Stack top ($21FF)
txs
; at startup all MPRs are set to 0, so init them
lda #$ff
- tam #1 ; 0000-1FFF = Hardware page
+ tam #%00000001 ; 0000-1FFF = Hardware page
lda #$F8
- tam #2 ; 2000-3FFF = Work RAM
+ tam #%00000010 ; 2000-3FFF = Work RAM
;lda #$F7
- ;tam #2 ; 4000-5FFF = Save RAM
+ ;tam #%00000100 ; 4000-5FFF = Save RAM
;lda #1
- ;tam #3 ; 6000-7FFF Page 2
+ ;tam #%00001000 ; 6000-7FFF Page 2
;lda #2
- ;tam #4 ; 8000-9FFF Page 3
+ ;tam #%00010000 ; 8000-9FFF Page 3
;lda #3
- ;tam #5 ; A000-BFFF Page 4
+ ;tam #%00100000 ; A000-BFFF Page 4
;lda #4
- ;tam #6 ; C000-DFFF Page 5
+ ;tam #%01000000 ; C000-DFFF Page 5
;lda #0
- ;tam #7 ; e000-fFFF hucard/syscard bank 0
+ ;tam #%10000000 ; e000-fFFF hucard/syscard bank 0
; Clear work RAM (2000-3FFF)
stz <$00
sta IRQ_MASK ; Interrupts off
stz IRQ_STATUS ; Acknowledge timer
- ;; i dont know why the heck this one doesnt
- ;; work when called from a constructor :/
- .import vdc_init
- jsr vdc_init
-
-;; jsr joy_init
+ ;; FIXME; i dont know why the heck this one doesnt work when called from a constructor :/
+ .import vdc_init
+ jsr vdc_init
; Turn on background and VD interrupt/IRQ1
-
lda #$05
sta IRQ_MASK ; IRQ1=on
- cli
-
-; Clear the BSS data
+ ; Clear the BSS data
+ jsr zerobss
- 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__)
+ ; Copy the .data segment to RAM
+ lda #<(__DATA_LOAD__)
+ sta ptr1
+ lda #>(__DATA_LOAD__)
+ sta ptr1+1
+ lda #<(__DATA_RUN__)
+ sta ptr2
+ lda #>(__DATA_RUN__)
+ sta ptr2+1
+ ldx #>(__DATA_SIZE__)
@l2:
- beq @s1 ; no more full pages
+ beq @s1 ; no more full pages
- ; copy one page
- ldy #0
+ ; copy one page
+ ldy #0
@l1:
- lda (ptr1),y
- sta (ptr2),y
- iny
- bne @l1
+ lda (ptr1),y
+ sta (ptr2),y
+ iny
+ bne @l1
- inc ptr1+1
- inc ptr2+1
+ inc ptr1+1
+ inc ptr2+1
- dex
- bne @l2
+ dex
+ bne @l2
- ; copy remaining bytes
+ ; copy remaining bytes
@s1:
-
- ; copy one page
- ldy #0
+ ; 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
+ lda (ptr1),y
+ sta (ptr2),y
+ iny
+ cpy #<(__DATA_SIZE__)
+ bne @l3
-; Init the Heap
- jsr initheap
+ ; setup the stack
+ lda #<(__RAM_START__+__RAM_SIZE__)
+ sta sp
+ lda #>(__RAM_START__+__RAM_SIZE__)
+ sta sp+1
-;jmp *
+ ; Call module constructors
+ jsr initlib
-; Call module constructors
+ cli ; allow IRQ only after constructors have run
- jsr initlib
+ ; Pass an empty command line
+ jsr push0 ; argc
+ jsr push0 ; argv
- .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.
+ 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
+ jsr donelib ; Run module destructors
- jmp start
+ ; reset the PCEngine (start over)
+ jmp start
; ------------------------------------------------------------------------
; System V-Blank Interupt
+; FIXME: hooks should be provided so the user can abuse the IRQ
; ------------------------------------------------------------------------
_irq1:
phy
- inc _tickcount
- bne @s
- inc _tickcount+1
-@s:
-
+ inc tickcount
+ bne @s1
+ inc tickcount+1
+ bne @s1
+ inc tickcount+2
+ bne @s1
+ inc tickcount+3
+@s1:
; Acknowlege interrupt
- ldaio VDC_CTRL
+ lda a:VDC_CTRL
ply
plx
; ------------------------------------------------------------------------
; 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 _irq2 ; $fff6 IRQ2 (External IRQ, BRK)
+ .word _irq1 ; $fff8 IRQ1 (VDC)
+ .word _timer ; $fffa Timer
+ .word _nmi ; $fffc NMI
+ .word start ; $fffe reset
projects / cc65 / blobdiff