; ; Startup code for cc65 (PCEngine version) ; ; by Groepaz/Hitmen ; based on code by Ullrich von Bassewitz ; ; 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 ; 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" .importzp sp .importzp ptr1,ptr2 ; ------------------------------------------------------------------------ ; Place the startup code in a special segment. .segment "STARTUP" start: ; setup the CPU and System-IRQ ; Initialize CPU sei nop csh ; set high speed CPU mode nop cld nop ; Setup stack and memory mapping ldx #$FF ; Stack top ($21FF) txs ; at startup all MPRs are set to 0, so init them lda #$ff tam #%00000001 ; 0000-1FFF = Hardware page lda #$F8 tam #%00000010 ; 2000-3FFF = Work RAM ;lda #$F7 ;tam #%00000100 ; 4000-5FFF = Save RAM ;lda #1 ;tam #%00001000 ; 6000-7FFF Page 2 ;lda #2 ;tam #%00010000 ; 8000-9FFF Page 3 ;lda #3 ;tam #%00100000 ; A000-BFFF Page 4 ;lda #4 ;tam #%01000000 ; C000-DFFF Page 5 ;lda #0 ;tam #%10000000 ; e000-fFFF hucard/syscard bank 0 ; Clear work RAM (2000-3FFF) stz <$00 tii $2000, $2001, $1FFF ; Initialize hardware stz TIMER_COUNT ; Timer off lda #$07 sta IRQ_MASK ; Interrupts off stz IRQ_STATUS ; Acknowledge timer ;; 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 ; Clear the BSS data jsr zerobss ; 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 ; 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__+__RAM_SIZE__) sta sp lda #>(__RAM_START__+__RAM_SIZE__) sta sp+1 ; Call module constructors jsr initlib 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 users code ; Call module destructors. This is also the _exit entry. _exit: jsr donelib ; Run module destructors ; reset the PCEngine (start over) jmp start ; ------------------------------------------------------------------------ ; System V-Blank Interupt ; FIXME: hooks should be provided so the user can abuse the IRQ ; ------------------------------------------------------------------------ _irq1: pha phx phy inc tickcount bne @s1 inc tickcount+1 bne @s1 inc tickcount+2 bne @s1 inc tickcount+3 @s1: ; Acknowlege interrupt lda a:VDC_CTRL ply plx pla rti _irq2: rti _nmi: rti _timer: stz IRQ_STATUS rti .export initmainargs initmainargs: rts ; ------------------------------------------------------------------------ ; hardware vectors ; ------------------------------------------------------------------------ .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