cc65/libsrc/gamate/crt0.s


        .export         Start, _exit

        .import         initlib, donelib, callmain
        .import         push0, _main, zerobss, copydata

        ; Linker generated symbols
        .import         __RAM_START__, __RAM_SIZE__

        .include        "zeropage.inc"
        .include        "gamate.inc"

Start:
        ; setup the CPU and System-IRQ

        ; Initialize CPU
        sei
        cld

        ldx     #0
        stx     ZP_IRQ_CTRL     ; disable calling cartridge IRQ/NMI handler

        ; Set up stack and memory mapping
        ;ldx     #$FF            ; Stack top ($01FF)
        dex
        txs

        ; Clear the BSS data
        jsr     zerobss

        ; Copy the .data segment to RAM
        jsr     copydata

        ; Set up the stack
        lda     #<(__RAM_START__+__RAM_SIZE__)
        ldx     #>(__RAM_START__+__RAM_SIZE__)
        sta     sp
        stx     sp + 1

        ; Call module constructors
        jsr     initlib

        lda     #1
        sta     ZP_IRQ_CTRL     ; enable calling cartridge IRQ/NMI handler
        cli                     ; allow IRQ only after constructors have run

        ; Pass an empty command line
        jsr     push0           ; argc
        jsr     push0           ; argv

        ldy     #4              ; Argument size
        jsr     _main           ; call the users code

        ; Call module destructors. This is also the _exit entry.
_exit:
        jsr     donelib         ; Run module destructors

        ; reset (start over)
        jmp     Start

        .export initmainargs
initmainargs:
        rts
some more fiddling 2015-11-22 18:02:47 +00:00
moved cart header into seperate file, moved nmi stub into several file, tweaked linker config 2015-11-29 15:01:36 +00:00			`.export Start, _exit`
some more fiddling 2015-11-22 18:02:47 +00:00
conio and most other stuff working now 2015-11-29 00:14:59 +00:00			`.import initlib, donelib, callmain`
			`.import push0, _main, zerobss, copydata`
some more fiddling 2015-11-22 18:02:47 +00:00
conio and most other stuff working now 2015-11-29 00:14:59 +00:00			`; Linker generated symbols`
			`.import __RAM_START__, __RAM_SIZE__`

			`.include "zeropage.inc"`
			`.include "gamate.inc"`
some more fiddling 2015-11-22 18:02:47 +00:00
moved cart header into seperate file, moved nmi stub into several file, tweaked linker config 2015-11-29 15:01:36 +00:00			`Start:`
conio and most other stuff working now 2015-11-29 00:14:59 +00:00			`; setup the CPU and System-IRQ`

			`; Initialize CPU`
			`sei`
			`cld`

more cleanup 2015-11-29 19:04:10 +00:00			`ldx #0`
			`stx ZP_IRQ_CTRL ; disable calling cartridge IRQ/NMI handler`

Use AX paradigm for stack initalization. 2016-03-07 00:44:19 +00:00			`; Set up stack and memory mapping`
more cleanup 2015-11-29 19:04:10 +00:00			`;ldx #$FF ; Stack top ($01FF)`
			`dex`
conio and most other stuff working now 2015-11-29 00:14:59 +00:00			`txs`

			`; Clear the BSS data`
			`jsr zerobss`

			`; Copy the .data segment to RAM`
			`jsr copydata`

Use AX paradigm for stack initalization. 2016-03-07 00:44:19 +00:00			`; Set up the stack`
conio and most other stuff working now 2015-11-29 00:14:59 +00:00			`lda #<(__RAM_START__+__RAM_SIZE__)`
Renamed RAM to MAIN for all disk based targets. The name RAM doesn't make much sense in general for a memeory area because i.e. the zero page is for sure RAM but is not part of the memory area named RAM. For disk based targets it makes sense to put the disk file more into focus and here MAIN means the main part of the file - in contrast to some header. Only for ROM based targets the name RAM is kept as it makes sense to focus on the difference between RAM and ROM. 2016-03-07 00:28:55 +00:00			`ldx #>(__RAM_START__+__RAM_SIZE__)`
conio and most other stuff working now 2015-11-29 00:14:59 +00:00			`sta sp`
Renamed RAM to MAIN for all disk based targets. The name RAM doesn't make much sense in general for a memeory area because i.e. the zero page is for sure RAM but is not part of the memory area named RAM. For disk based targets it makes sense to put the disk file more into focus and here MAIN means the main part of the file - in contrast to some header. Only for ROM based targets the name RAM is kept as it makes sense to focus on the difference between RAM and ROM. 2016-03-07 00:28:55 +00:00			`stx sp + 1`
conio and most other stuff working now 2015-11-29 00:14:59 +00:00
			`; Call module constructors`
			`jsr initlib`

more cleanup 2015-11-29 19:04:10 +00:00			`lda #1`
			`sta ZP_IRQ_CTRL ; enable calling cartridge IRQ/NMI handler`
Renamed RAM to MAIN for all disk based targets. The name RAM doesn't make much sense in general for a memeory area because i.e. the zero page is for sure RAM but is not part of the memory area named RAM. For disk based targets it makes sense to put the disk file more into focus and here MAIN means the main part of the file - in contrast to some header. Only for ROM based targets the name RAM is kept as it makes sense to focus on the difference between RAM and ROM. 2016-03-07 00:28:55 +00:00			`cli ; allow IRQ only after constructors have run`
conio and most other stuff working now 2015-11-29 00:14:59 +00:00
			`; Pass an empty command line`
			`jsr push0 ; argc`
			`jsr push0 ; argv`

			`ldy #4 ; Argument size`
			`jsr _main ; call the users code`

			`; Call module destructors. This is also the _exit entry.`
			`_exit:`
			`jsr donelib ; Run module destructors`

			`; reset (start over)`
moved cart header into seperate file, moved nmi stub into several file, tweaked linker config 2015-11-29 15:01:36 +00:00			`jmp Start`
some more fiddling 2015-11-22 18:02:47 +00:00
conio and most other stuff working now 2015-11-29 00:14:59 +00:00			`.export initmainargs`
			`initmainargs:`
			`rts`