; ; Startup code for cc65 (C16 version) ; ; This must be the *first* file on the linker command line ; ; 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 .import initlib, donelib .import push0, callmain, zerobss .import MEMTOP, RESTOR, BSOUT, CLRCH .include "zeropage.inc" .include "../plus4/plus4.inc" ; ------------------------------------------------------------------------ ; Place the startup code in a special segment. .segment "STARTUP" ; BASIC header with a SYS call .word Head ; Load address Head: .word @Next .word .version ; Line number .byte $9E,"4109" ; SYS 4109 .byte $00 ; End of BASIC line @Next: .word 0 ; BASIC end marker ; ------------------------------------------------------------------------ ; Actual code ldx #zpspace-1 L1: lda sp,x sta zpsave,x ; save the zero page locations we need dex bpl L1 ; Close open files jsr CLRCH ; 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: jsr donelib ; Run module destructors ; Restore system stuff ldx spsave txs ; Copy back the zero page stuff ldx #zpspace-1 L2: lda zpsave,x sta sp,x dex bpl L2 ; Reset changed vectors jmp RESTOR .data zpsave: .res zpspace .bss spsave: .res 1