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Synertek Systems Sym-1 machine-specific files

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Wayne Parham
2021-05-09 16:34:53 -05:00
parent 07bd5089ec
commit 6e79379405
23 changed files with 2088 additions and 0 deletions
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libsrc/sym1/crt0.s Normal file
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; ---------------------------------------------------------------------------
; crt0.s
;
; for Sym-1
;
; Wayne Parham
;
; wayne@parhamdata.com
; ---------------------------------------------------------------------------
.export _init, _exit
.export __STARTUP__ : absolute = 1 ; Mark as startup
.import _main
.import initlib, donelib, copydata, zerobss
.import __RAM_START__, __RAM_SIZE__ ; Linker generated
.import __STACKSIZE__ ; Linker generated
.include "zeropage.inc"
.include "sym1.inc"
; ---------------------------------------------------------------------------
; Place the startup code in a special segment
.segment "STARTUP"
; ---------------------------------------------------------------------------
; A little light housekeeping
_init: jsr ACCESS ; Unlock System RAM
cld ; Clear decimal mode
; ---------------------------------------------------------------------------
; Turn off console echo
lda TECHO
and #$7F
sta TECHO
; ---------------------------------------------------------------------------
; Set cc65 argument stack pointer
lda #<(__RAM_START__ + __RAM_SIZE__)
sta sp
lda #>(__RAM_START__ + __RAM_SIZE__)
sta sp+1
; ---------------------------------------------------------------------------
; Initialize memory storage
jsr zerobss ; Clear BSS segment
jsr copydata ; Initialize DATA segment
jsr initlib ; Run constructors
; ---------------------------------------------------------------------------
; Call main()
jsr _main
; ---------------------------------------------------------------------------
; Back from main (this is also the _exit entry)
_exit: jsr donelib ; Run destructors
lda TECHO
ora #$80 ; Re-enable console echo
sta TECHO
jsr NACCES ; Lock System RAM
rts ; Re-enter Sym-1 monitor
; ---------------------------------------------------------------------------