;
; Startup code for cc65 (Vic20 version)
-;
-; This must be the *first* file on the linker command line
;
.export _exit
- .import initlib, donelib
+ .export __STARTUP__ : absolute = 1 ; Mark as startup
+ .import initlib, donelib, callirq
.import zerobss, push0
- .import _main
- .import __RAM_START__, __RAM_SIZE__ ; Linker generated
+ .import callmain
+ .import RESTOR, BSOUT, CLRCH
+ .import __INTERRUPTOR_COUNT__
+ .import __RAM_START__, __RAM_SIZE__ ; Linker generated
- .include "vic20.inc"
- .include "../cbm/cbm.inc"
+ .include "zeropage.inc"
+ .include "vic20.inc"
; ------------------------------------------------------------------------
-; Define and export the ZP variables for the Vic20 runtime
-
- .exportzp sp, sreg, regsave
- .exportzp ptr1, ptr2, ptr3, ptr4
- .exportzp tmp1, tmp2, tmp3, tmp4
- .exportzp regbank, zpspace
-
-.zeropage
+; Place the startup code in a special segment.
-zpstart = *
-sp: .res 2 ; Stack pointer
-sreg: .res 2 ; Secondary register/high 16 bit for longs
-regsave: .res 4 ; slot to save/restore (E)AX into
-ptr1: .res 2
-ptr2: .res 2
-ptr3: .res 2
-ptr4: .res 2
-tmp1: .res 1
-tmp2: .res 1
-tmp3: .res 1
-tmp4: .res 1
-regbank: .res 6 ; 6 byte register bank
+.segment "STARTUP"
-zpspace = * - zpstart ; Zero page space allocated
-
-.code
-
-; ------------------------------------------------------------------------
; BASIC header with a SYS call
- .org $FFF
.word Head ; Load address
Head: .word @Next
- .word 1000 ; Line number
- .byte $9E,"4109" ; SYS 2061
+ .word .version ; Line number
+ .byte $9E ; SYS token
+ .byte <(((@Start / 1000) .mod 10) + $30)
+ .byte <(((@Start / 100) .mod 10) + $30)
+ .byte <(((@Start / 10) .mod 10) + $30)
+ .byte <(((@Start / 1) .mod 10) + $30)
.byte $00 ; End of BASIC line
@Next: .word 0 ; BASIC end marker
- .reloc
+@Start:
; ------------------------------------------------------------------------
; Actual code
tsx
stx spsave ; Save the system stack ptr
-; lda $01
-; sta mmusave ; Save the memory configuration
-; and #$F8
-; ora #$06 ; Enable kernal+I/O, disable basic
-; sta $01
-
lda #<(__RAM_START__ + __RAM_SIZE__)
sta sp
lda #>(__RAM_START__ + __RAM_SIZE__)
sta sp+1 ; Set argument stack ptr
+; If we have IRQ functions, chain our stub into the IRQ vector
+
+ lda #<__INTERRUPTOR_COUNT__
+ beq NoIRQ1
+ lda IRQVec
+ ldx IRQVec+1
+ sta IRQInd+1
+ stx IRQInd+2
+ lda #<IRQStub
+ ldx #>IRQStub
+ sei
+ sta IRQVec
+ stx IRQVec+1
+ cli
+
; Call module constructors
- jsr initlib
+NoIRQ1: jsr initlib
-; Pass an empty command line
+; Push arguments and call main()
- jsr push0 ; argc
- jsr push0 ; argv
+ jsr callmain
- ldy #4 ; Argument size
- jsr _main ; call the users code
+; Back from main (This is also the _exit entry). Run module destructors
-; Call module destructors. This is also the _exit entry.
+_exit: jsr donelib
-_exit: jsr donelib ; Run module destructors
+; Reset the IRQ vector if we chained it.
-; Restore system stuff
-
- ldx spsave
- txs ; Restore stack pointer
-; lda mmusave
-; sta $01 ; Restore memory configuration
+ pha ; Save the return code on stack
+ lda #<__INTERRUPTOR_COUNT__
+ beq NoIRQ2
+ lda IRQInd+1
+ ldx IRQInd+2
+ sei
+ sta IRQVec
+ stx IRQVec+1
+ cli
; Copy back the zero page stuff
- ldx #zpspace-1
+NoIRQ2: ldx #zpspace-1
L2: lda zpsave,x
sta sp,x
dex
bpl L2
+; Place the program return code into ST
+
+ pla
+ sta ST
+
+; Restore the stack pointer
+
+ ldx spsave
+ txs
+
; Reset changed vectors, back to basic
jmp RESTOR
+; ------------------------------------------------------------------------
+; The IRQ vector jumps here, if condes routines are defined with type 2.
+
+IRQStub:
+ cld ; Just to be sure
+ jsr callirq ; Call the functions
+ jmp IRQInd ; Jump to the saved IRQ vector
+
+; ------------------------------------------------------------------------
+; Data
+
.data
+IRQInd: jmp $0000
+
+.segment "ZPSAVE"
+
zpsave: .res zpspace
.bss
spsave: .res 1
-mmusave:.res 1