;
; Startup code for cc65 (C128 version)
-;
-; This must be the *first* file on the linker command line
;
- .export _exit
- .import __hinit, initconio, doneconio, zerobss
- .import push0, doatexit, _main
+ .export _exit
+ .export __STARTUP__ : absolute = 1 ; Mark as startup
+ .import initlib, donelib
+ .import zerobss
+ .import push0, callmain
+ .import RESTOR, BSOUT, CLRCH
+ .import __RAM_START__, __RAM_SIZE__, __STACKSIZE__
+ .importzp ST
- .include "c128.inc"
- .include "../cbm/cbm.inc"
+ .include "zeropage.inc"
+ .include "c128.inc"
-; ------------------------------------------------------------------------
-; Define and export the ZP variables for the C64 runtime
-
- .exportzp sp, sreg, regsave
- .exportzp ptr1, ptr2, ptr3, ptr4
- .exportzp tmp1, tmp2, tmp3, tmp4
- .exportzp regbank, zpspace
-
-sp = $02 ; stack pointer
-sreg = $04 ; secondary register/high 16 bit for longs
-regsave = $06 ; slot to save/restore (E)AX into
-ptr1 = $0A ;
-ptr2 = $0C
-ptr3 = $0E
-ptr4 = $10
-tmp1 = $12
-tmp2 = $13
-tmp3 = $14
-tmp4 = $15
-regbank = $16 ; 6 byte register bank
-zpspace = $1A ; Zero page space allocated
; ------------------------------------------------------------------------
-; BASIC header with a SYS call
+; Startup code
- .org $1BFF
- .word Head ; Load address
-Head: .word @Next
- .word 1000 ; Line number
- .byte $9E,"7181" ; SYS 7181
- .byte $00 ; End of BASIC line
-@Next: .word 0 ; BASIC end marker
- .reloc
+.segment "STARTUP"
-; ------------------------------------------------------------------------
-; Actual code
+Start:
- ldy #zpspace-1
-L1: lda sp,y
- sta zpsave,y ; save the zero page locations we need
- dey
- bpl L1
+; Switch to the second charset
-; Close open files
+ lda #14
+ jsr BSOUT
- jsr CLRCH
+; Before doing anything else, we have to setup our banking configuration.
+; Otherwise just the lowest 16K are actually RAM. Writing through the ROM
+; to the underlying RAM works, but it is bad style.
-; Switch to second charset
+ lda MMU_CR ; Get current memory configuration...
+ pha ; ...and save it for later
+ lda #MMU_CFG_CC65 ; Bank0 with kernal ROM
+ sta MMU_CR
- lda #14
- jsr BSOUT
+; Save the zero page locations we need
-; Get the current MMU setting and save it. Set new memory config.
-
- lda MMU_CR ; Get current memory configuration...
- pha ; ...and save it for later
- lda #$0E ; Bank0 with kernal ROM
- sta MMU_CR
+ ldx #zpspace-1
+L1: lda sp,x
+ sta zpsave,x
+ dex
+ bpl L1
; Clear the BSS data
- jsr zerobss
+ jsr zerobss
; Save system stuff and setup the stack
- pla ; Get MMU setting
- sta mmusave
+ pla ; Get MMU setting
+ sta mmusave
- tsx
- stx spsave ; save system stk ptr
+ tsx
+ stx spsave ; Save the system stack pointer
- lda #<$C000
- sta sp
- lda #>$C000
- sta sp+1
+ lda #<(__RAM_START__ + __RAM_SIZE__ + __STACKSIZE__)
+ sta sp
+ lda #>(__RAM_START__ + __RAM_SIZE__ + __STACKSIZE__)
+ sta sp+1 ; Set argument stack ptr
-; Initialize the heap
+; Call module constructors
- jsr __hinit
+ jsr initlib
-; Initialize conio stuff
+; Set the bank for the file name to our execution bank. We must do this,
+; *after* calling constructors, because some of them may depend on the
+; original value of this register.
- jsr initconio
+ lda #0
+ sta FNAM_BANK
-; Pass an empty command line
+; Push arguments and call main()
- jsr push0 ; argc
- jsr push0 ; argv
+ jsr callmain
- ldy #4 ; Argument size
- jsr _main ; call the users code
+; Back from main (this is also the _exit entry). Run module destructors
-; fall thru to exit...
+_exit: pha ; Save the return code on stack
+ jsr donelib
-_exit: jsr doatexit ; call exit functions
+; Copy back the zero page stuff
-; Reset the conio stuff
+ ldx #zpspace-1
+L2: lda zpsave,x
+ sta sp,x
+ dex
+ bpl L2
- jsr doneconio
+; Place the program return code into ST
-; Reset stack and the MMU
+ pla
+ sta ST
- ldx spsave ; Patched at runtime
- txs
- lda mmusave ; Patched at runtime
- sta MMU_CR
+; Reset the stack and the memory configuration
-; Copy back the zero page stuff
+ ldx spsave
+ txs
+ ldx mmusave
+ stx MMU_CR
- ldy #zpspace-1
-L2: lda zpsave,y
- sta sp,y
- dey
- bpl L2
+; Done, return to BASIC
-; Done
+ rts
- jmp RESTOR
+; ------------------------------------------------------------------------
+; Data
-.data
-zpsave: .res zpspace
+.segment "ZPSAVE"
-.bss
-spsave: .res 1
-mmusave:.res 1
+zpsave: .res zpspace
+; ------------------------------------------------------------------------
+.bss
+spsave: .res 1
+mmusave:.res 1
projects / cc65 / blobdiff