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https://github.com/cc65/cc65.git
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164 lines
2.8 KiB
ArmAsm
164 lines
2.8 KiB
ArmAsm
;
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; Startup code for cc65 (Oric version)
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;
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; By Debrune Jérôme <jede@oric.org> and Ullrich von Bassewitz <uz@cc65.org>
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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, callirq
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.import __INTERRUPTOR_COUNT__
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.import __RAM_START__, __RAM_SIZE__
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.import __ZPSAVE_LOAD__, __STACKSIZE__
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.include "zeropage.inc"
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.include "atmos.inc"
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; ------------------------------------------------------------------------
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; Oric tape header
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.segment "TAPEHDR"
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.byte $16, $16, $16 ; Sync bytes
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.byte $24 ; End of header marker
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.byte $00 ; $2B0
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.byte $00 ; $2AF
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.byte $80 ; $2AE Machine code flag
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.byte $C7 ; $2AD Autoload flag
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.dbyt __ZPSAVE_LOAD__ - 1 ; $2AB
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.dbyt __RAM_START__ ; $2A9
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.byte $00 ; $2A8
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.byte ((.VERSION >> 8) & $0F) + '0'
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.byte ((.VERSION >> 4) & $0F) + '0'
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.byte (.VERSION & $0F) + '0'
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.byte $00 ; Zero terminated compiler version
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; ------------------------------------------------------------------------
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; Place the startup code in a special segment.
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.segment "STARTUP"
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; Save the zero page area we're about to use
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ldx #zpspace-1
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L1: lda sp,x
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sta zpsave,x ; Save the zero page locations we need
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dex
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bpl L1
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; Clear the BSS data
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jsr zerobss
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; Unprotect columns 0 and 1
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lda STATUS
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sta stsave
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and #%11011111
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sta STATUS
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; Save system stuff and setup the stack
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tsx
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stx spsave ; Save system stk ptr
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lda #<(__RAM_START__ + __RAM_SIZE__ + __STACKSIZE__)
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sta sp
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lda #>(__RAM_START__ + __RAM_SIZE__ + __STACKSIZE__)
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sta sp+1 ; Set argument stack ptr
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; If we have IRQ functions, chain our stub into the IRQ vector
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lda #<__INTERRUPTOR_COUNT__
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beq NoIRQ1
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lda IRQVec
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ldx IRQVec+1
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sta IRQInd+1
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stx IRQInd+2
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lda #<IRQStub
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ldx #>IRQStub
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sei
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sta IRQVec
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stx IRQVec+1
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cli
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; Call module constructors
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NoIRQ1: jsr initlib
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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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; Reset the IRQ vector if we chained it.
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pha ; Save the return code on stack
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lda #<__INTERRUPTOR_COUNT__
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beq NoIRQ2
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lda IRQInd+1
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ldx IRQInd+2
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sei
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sta IRQVec
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stx IRQVec+1
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cli
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; Restore system stuff
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NoIRQ2: ldx spsave
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txs
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lda stsave
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sta STATUS
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; Copy back the zero page stuff
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ldx #zpspace-1
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L2: lda zpsave,x
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sta sp,x
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dex
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bpl L2
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; Back to BASIC
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rts
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; ------------------------------------------------------------------------
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; The IRQ vector jumps here, if condes routines are defined with type 2.
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IRQStub:
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cld ; Just to be sure
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pha
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txa
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pha
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tya
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pha
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jsr callirq ; Call the functions
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pla
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tay
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pla
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tax
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pla
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jmp IRQInd ; Jump to the saved IRQ vector
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; ------------------------------------------------------------------------
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; Data
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.data
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IRQInd: jmp $0000
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.segment "ZPSAVE"
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zpsave: .res zpspace
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.bss
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spsave: .res 1
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stsave: .res 1
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