; Startup code for cc65 (C64 version)
;
- .export _exit
+ .export _exit
.export __STARTUP__ : absolute = 1 ; Mark as startup
- .import initlib, donelib, callirq
- .import zerobss
- .import callmain
+ .import initlib, donelib
+ .import zerobss
+ .import callmain
.import RESTOR, BSOUT, CLRCH
- .import __INTERRUPTOR_COUNT__
- .import __RAM_START__, __RAM_SIZE__ ; Linker generated
+ .import __RAM_START__, __RAM_SIZE__ ; Linker generated
+ .import __STACKSIZE__ ; Linker generated
+ .importzp ST
.include "zeropage.inc"
- .include "c64.inc"
+ .include "c64.inc"
-; ------------------------------------------------------------------------
-; BASIC header with a SYS call
-
-.segment "EXEHDR"
-
- .word Head ; Load address
-Head: .word @Next
- .word .version ; Line number
- .byte $9E ; SYS token
- .byte <(((Start / 1000) .mod 10) + '0')
- .byte <(((Start / 100) .mod 10) + '0')
- .byte <(((Start / 10) .mod 10) + '0')
- .byte <(((Start / 1) .mod 10) + '0')
- .byte $00 ; End of BASIC line
-@Next: .word 0 ; BASIC end marker
-
; ------------------------------------------------------------------------
; Startup code
-.segment "STARTUP"
+.segment "STARTUP"
Start:
; Save the zero page locations we need
- ldx #zpspace-1
-L1: lda sp,x
- sta zpsave,x
- dex
- bpl L1
+ ldx #zpspace-1
+L1: lda sp,x
+ sta zpsave,x
+ dex
+ bpl L1
; Switch to second charset
- lda #14
- jsr BSOUT
+ lda #14
+ jsr BSOUT
; Switch off the BASIC ROM
- lda $01
- pha ; Remember the value
- and #$F8
- ora #$06 ; Enable kernal+I/O, disable basic
- sta $01
+ lda $01
+ pha ; Remember the value
+ and #$F8
+ ora #$06 ; Enable kernal+I/O, disable basic
+ sta $01
; Clear the BSS data
- jsr zerobss
+ jsr zerobss
; Save system settings and setup the stack
pla
- sta mmusave ; Save the memory configuration
-
- tsx
- stx spsave ; Save the system stack ptr
-
- 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
+ sta mmusave ; Save the memory configuration
+
+ tsx
+ stx spsave ; Save the system stack ptr
+
+ lda #<(__RAM_START__ + __RAM_SIZE__ + __STACKSIZE__)
+ sta sp
+ lda #>(__RAM_START__ + __RAM_SIZE__ + __STACKSIZE__)
+ sta sp+1 ; Set argument stack ptr
; Call module constructors
-NoIRQ1: jsr initlib
+ jsr initlib
; Push arguments and call main
; Back from main (This is also the _exit entry). Run module destructors
-_exit: jsr donelib
-
-
-; Reset the IRQ vector if we chained it.
-
- 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
+_exit: pha ; Save the return code on stack
+ jsr donelib
; Copy back the zero page stuff
-NoIRQ2: ldx #zpspace-1
-L2: lda zpsave,x
- sta sp,x
- dex
- bpl L2
+ ldx #zpspace-1
+L2: lda zpsave,x
+ sta sp,x
+ dex
+ bpl L2
; Place the program return code into ST
- pla
- sta ST
+ pla
+ sta ST
; Restore system stuff
- ldx spsave
- txs ; Restore stack pointer
- ldx mmusave
- stx $01 ; Restore memory configuration
+ ldx spsave
+ txs ; Restore stack pointer
+ ldx mmusave
+ stx $01 ; Restore memory configuration
-; Reset changed vectors, back to basic
+; 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
+ rts
; ------------------------------------------------------------------------
; Data
-.data
-
-IRQInd: jmp $0000
-
.segment "ZPSAVE"
-zpsave: .res zpspace
+zpsave: .res zpspace
.bss
-spsave: .res 1
-mmusave:.res 1
+spsave: .res 1
+mmusave:.res 1
projects / cc65 / blobdiff