; Startup code for cc65 (PET version)
;
- .export _exit
+ .export _exit
.export __STARTUP__ : absolute = 1 ; Mark as startup
- .import initlib, donelib, callirq
- .import zerobss, push0
- .import callmain
+ .import initlib, donelib
+ .import zerobss, push0
+ .import callmain
.import CLRCH, BSOUT
- .import __INTERRUPTOR_COUNT__
- .importzp ST
+ .importzp ST
.include "zeropage.inc"
- .include "pet.inc"
- .include "../cbm/cbm.inc"
+ .include "pet.inc"
+ .include "../cbm/cbm.inc"
; ------------------------------------------------------------------------
; Startup code
-.segment "STARTUP"
+.segment "STARTUP"
Start:
-; Save the zero page locations we need
+; Save the zero-page locations that 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. The routine that is called by BSOUT to switch the
-; character set will use FNLEN as temporary storage - YUCK! Since the
-; initmainargs routine, which parses the command line for arguments needs this
+; Switch to the second charset. The routine that is called by BSOUT to switch the
+; character set will use FNLEN as temporary storage -- YUCK! Since the
+; initmainargs routine, which parses the command line for arguments, needs that
; information, we need to save and restore it here.
; Thanks to Stefan Haubenthal for this information!
lda FNLEN
pha ; Save FNLEN
- lda #14
-; sta $E84C ; See PET FAQ
- jsr BSOUT
+ lda #14
+; sta $E84C ; See PET FAQ
+ jsr BSOUT
pla
sta FNLEN ; Restore FNLEN
-; Clear the BSS data
+; Clear the BSS data.
- jsr zerobss
+ jsr zerobss
-; Save system stuff and setup the stack
+; Save some system stuff; and, set up the stack.
- tsx
- stx spsave ; Save the system stack ptr
+ tsx
+ stx spsave ; Save the system stack ptr
- lda MEMSIZE
- sta sp
- lda MEMSIZE+1
- sta sp+1 ; Set argument stack ptr
+ lda MEMSIZE
+ sta sp
+ lda MEMSIZE+1
+ sta sp+1 ; Set argument stack ptr
-; If we have IRQ functions, chain our stub into the IRQ vector
+; Call the module constructors.
- 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
+; Push the command-line arguments; and, call main().
-NoIRQ1: jsr initlib
+ jsr callmain
-; Push arguments and call main()
+; Call the module destructors. This is also the exit() entry.
- jsr callmain
+_exit: pha ; Save the return code on stack
+ jsr donelib
-; Call module destructors. This is also the _exit entry.
+; Copy back the zero-page stuff.
-_exit: pha ; Save the return code on stack
- jsr donelib
+ ldx #zpspace-1
+L2: lda zpsave,x
+ sta sp,x
+ dex
+ bpl L2
-; Reset the IRQ vector if we chained it.
+; Store the program return code into BASIC's status variable.
- lda #<__INTERRUPTOR_COUNT__
- beq NoIRQ2
- lda IRQInd+1
- ldx IRQInd+2
- sei
- sta IRQVec
- stx IRQVec+1
- cli
-
-; Copy back the zero page stuff
-
-NoIRQ2: ldx #zpspace-1
-L2: lda zpsave,x
- sta sp,x
- dex
- bpl L2
-
-; Store the program return code into ST
-
- pla
- sta ST
-
-; Restore the stack pointer
-
- ldx spsave
- txs ; Restore stack pointer
+ pla
+ sta ST
-; Back to basic
+; Restore the stack pointer.
- rts
+ ldx spsave
+ txs ; Restore stack pointer
-; ------------------------------------------------------------------------
-; The IRQ vector jumps here, if condes routines are defined with type 2.
+; Back to BASIC.
-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 "INIT"
-.segment "ZPSAVE"
+zpsave: .res zpspace
-zpsave: .res zpspace
+; ------------------------------------------------------------------------
.bss
-spsave: .res 1
-mmusave:.res 1
-
+spsave: .res 1
+mmusave:.res 1
projects / cc65 / blobdiff