; ; Startup code for cc65 (C16 version) ; ; Note: The C16 is actually the Plus/4 with just 16KB of memory. So many ; things are similar here, and we even use the plus4.inc include file. ; .export _exit .export __STARTUP__ : absolute = 1 ; Mark as startup .import initlib, donelib .import callmain, zerobss .import MEMTOP, RESTOR, BSOUT, CLRCH .importzp ST .include "zeropage.inc" .include "plus4.inc" ; ------------------------------------------------------------------------ ; Startup code .segment "STARTUP" Start: ; Save the zero page locations we need ldx #zpspace-1 L1: lda sp,x sta zpsave,x dex bpl L1 ; Switch to second charset lda #14 jsr BSOUT ; Clear the BSS data jsr zerobss ; Save system stuff and setup the stack tsx stx spsave ; save system stk ptr sec jsr MEMTOP ; Get top memory cpy #$80 ; We can only use the low 32K :-( bcc MemOk ldy #$80 ldx #$00 MemOk: stx sp sty sp+1 ; set argument stack ptr ; Call module constructors jsr initlib ; Push arguments and call main() jsr callmain ; Call module destructors. This is also the _exit entry. _exit: pha ; Save the return code on stack jsr donelib ; Run module destructors ; Copy back the zero page stuff ldx #zpspace-1 L2: lda zpsave,x sta sp,x dex bpl L2 ; Store the return code into ST pla sta ST ; Restore the stack pointer ldx spsave txs ; Back to BASIC rts ; ------------------------------------------------------------------------ .segment "ZPSAVE" zpsave: .res zpspace ; ------------------------------------------------------------------------ .bss spsave: .res 1