mirror of
https://github.com/cc65/cc65.git
synced 2024-07-07 04:29:01 +00:00
7ebaec1802
Saves 19 bytes code (in the exe file) and reduces memory footprint of the program by 45 bytes (code & bss).
146 lines
3.0 KiB
ArmAsm
146 lines
3.0 KiB
ArmAsm
;
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; Startup code for cc65 (ATARI version)
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;
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; Contributing authors:
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; Mark Keates
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; Freddy Offenga
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; Christian Groessler
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; Stefan Haubenthal
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;
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.export _exit
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.export __STARTUP__ : absolute = 1 ; Mark as startup
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.import initlib, donelib
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.import callmain, zerobss
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.import __STARTUP_LOAD__, __BSS_LOAD__
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.import __RESERVED_MEMORY__
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.include "zeropage.inc"
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.include "atari.inc"
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; ------------------------------------------------------------------------
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; EXE header
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.segment "EXEHDR"
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.word $FFFF
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.word __STARTUP_LOAD__
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.word __BSS_LOAD__ - 1
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; ------------------------------------------------------------------------
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; Actual code
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.segment "STARTUP"
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rts ; fix for SpartaDOS / OS/A+
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; they first call the entry point from AUTOSTRT and
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; then the load addess (this rts here).
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; We point AUTOSTRT directly after the rts.
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; Real entry point:
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; Clear the BSS data
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jsr zerobss
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; Setup the stack
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tsx
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stx spsave
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; Report memory usage
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lda APPMHI
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sta appmsav ; remember old APPMHI value
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lda APPMHI+1
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sta appmsav+1
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sec
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lda MEMTOP
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sbc #<__RESERVED_MEMORY__
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sta APPMHI ; initialize our APPMHI value
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sta sp ; setup runtime stack part 1
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lda MEMTOP+1
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sbc #>__RESERVED_MEMORY__
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sta APPMHI+1
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sta sp+1 ; setup runtime stack part 2
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; Call module constructors
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jsr initlib
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; Set left margin to 0
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lda LMARGN
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sta old_lmargin
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ldy #0
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sty LMARGN
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; Set keyb to upper/lowercase mode
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ldx SHFLOK
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stx old_shflok
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sty SHFLOK
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; Initialize conio stuff
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dey ; Set X to $FF
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sty CH
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; Push arguments and call main
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jsr callmain
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; Call module destructors. This is also the _exit entry.
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_exit: jsr donelib ; Run module destructors
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; Restore system stuff
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ldx spsave
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txs ; Restore stack pointer
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; Restore left margin
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lda old_lmargin
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sta LMARGN
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; Restore kb mode
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lda old_shflok
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sta SHFLOK
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; Restore APPMHI
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lda appmsav
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sta APPMHI
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lda appmsav+1
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sta APPMHI+1
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; Turn on cursor
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ldx #0
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stx CRSINH
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; Back to DOS
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rts
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; *** end of main startup code
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; ------------------------------------------------------------------------
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.bss
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spsave: .res 1
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appmsav: .res 1
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old_shflok: .res 1
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old_lmargin: .res 1
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.segment "AUTOSTRT"
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.word RUNAD ; defined in atari.inc
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.word RUNAD+1
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.word __STARTUP_LOAD__ + 1
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