;
; 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 callmain
+ .import RESTOR, BSOUT, CLRCH
+ .import __INTERRUPTOR_COUNT__
.import __RAM_START__, __RAM_SIZE__ ; Linker generated
.include "zeropage.inc"
.include "vic20.inc"
- .include "../cbm/cbm.inc"
; ------------------------------------------------------------------------
+; Place the startup code in a special segment.
+
+.segment "STARTUP"
+
; BASIC header with a SYS call
-.segment "EXEHDR"
.word Head ; Load address
Head: .word @Next
- .word 1000 ; Line number
+ .word .version ; Line number
.byte $9E ; SYS token
.byte <(((@Start / 1000) .mod 10) + $30)
.byte <(((@Start / 100) .mod 10) + $30)
; ------------------------------------------------------------------------
; Actual code
-.code
-
ldx #zpspace-1
L1: lda sp,x
sta zpsave,x ; Save the zero page locations we need
lda #>(__RAM_START__ + __RAM_SIZE__)
sta sp+1 ; Set argument stack ptr
-; Call module constructors
+; 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
- jsr initlib
+; Call module constructors
-; Pass an empty command line
+NoIRQ1: jsr initlib
- jsr push0 ; argc
- jsr push0 ; argv
+; Push arguments and call main()
- ldy #4 ; Argument size
- jsr _main ; call the users code
+ jsr callmain
-; Call module destructors. This is also the _exit entry.
+; Back from main (This is also the _exit entry). Run module destructors
-_exit: jsr donelib ; Run module destructors
+_exit: jsr donelib
-; Restore system stuff
+; Reset the IRQ vector if we chained it.
- ldx spsave
- txs ; Restore stack pointer
+ 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