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Startup code with interruptor support by Oliver Schmidt
git-svn-id: svn://svn.cc65.org/cc65/trunk@3479 b7a2c559-68d2-44c3-8de9-860c34a00d81
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@ -5,89 +5,55 @@
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;
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.export _exit, __Exit
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.import initlib, donelib
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.import zerobss
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.import initlib, donelib
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.import callmain, callirq
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.import __STARTUP_LOAD__, __BSS_LOAD__ ; Linker generated
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.import callmain
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.import __INTERRUPTOR_COUNT__ ; Linker generated
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.include "zeropage.inc"
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.include "apple2.inc"
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.include "mli.inc"
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; ------------------------------------------------------------------------
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; The executable header
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.segment "EXEHDR"
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.word __STARTUP_LOAD__ ; Start address
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.addr __STARTUP_LOAD__ ; Start address
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.word __BSS_LOAD__ - __STARTUP_LOAD__ ; Size
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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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; ProDOS TechRefMan, chapter 5.2.1:
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; "For maximum interrupt efficiency, a system program should not use more
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; than the upper 3/4 of the stack."
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; "For maximum interrupt efficiency, a system program should not
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; use more than the upper 3/4 of the stack."
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ldx #$FF
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txs ; Init stack pointer
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; Save the zero page locations we need
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ldx #zpspace-1
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: lda sp,x
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sta zpsave,x
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dex
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bpl :-
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; Save the original RESET vector
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ldx #$02
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: lda SOFTEV,x
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sta rvsave,x
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dex
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bpl :-
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; ProDOS TechRefMan, chapter 5.3.5:
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; "Your system program should place in the RESET vector the address of a
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; routine that ... closes the files."
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ldx #<_exit
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lda #>_exit
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jsr reset ; Setup RESET vector
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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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lda HIMEM
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sta sp
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lda HIMEM+1
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sta sp+1 ; Set argument stack ptr
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; Call module constructors
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jsr initlib
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; Push arguments and call main()
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jsr callmain
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; Delegate all further processing to keep STARTUP small
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jsr init
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; Avoid re-entrance of donelib. This is also the _exit entry
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_exit: ldx #<__Exit
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lda #>__Exit
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jsr reset ; Setup RESET vector
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; Call module destructors
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; Check for valid interrrupt vector table entry number
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lda intnum
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beq :+
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jsr donelib
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; Deallocate interrupt vector table entry
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dec params ; Adjust parameter count
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jsr ENTRY
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.byte $41 ; Dealloc interrupt
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.addr params
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; Call module destructors
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: jsr donelib
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; Restore the original RESET vector. This is also the __Exit entry
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__Exit: ldx #$02
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: lda rvsave,x
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sta SOFTEV,x
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@ -95,7 +61,6 @@ __Exit: ldx #$02
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bpl :-
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; Copy back the zero page stuff
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ldx #zpspace-1
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: lda zpsave,x
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sta sp,x
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@ -103,19 +68,90 @@ __Exit: ldx #$02
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bpl :-
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; ProDOS TechRefMan, chapter 5.2.1:
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; "System programs should set the stack pointer to $FF at the warm-start
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; entry point."
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; "System programs should set the stack pointer to $FF at the
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; warm-start entry point."
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ldx #$FF
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txs ; Re-init stack pointer
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; Back to DOS
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jmp DOSWARM
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; ------------------------------------------------------------------------
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; Setup RESET vector
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.segment "INIT"
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; Save the zero page locations we need
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init: ldx #zpspace-1
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: lda sp,x
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sta zpsave,x
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dex
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bpl :-
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; Save the original RESET vector
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ldx #$02
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: lda SOFTEV,x
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sta rvsave,x
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dex
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bpl :-
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; ProDOS TechRefMan, chapter 5.3.5:
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; "Your system program should place in the RESET vector the
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; address of a routine that ... closes the files."
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ldx #<_exit
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lda #>_exit
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jsr reset ; Setup RESET vector
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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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lda HIMEM
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sta sp
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lda HIMEM+1
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sta sp+1 ; Set argument stack ptr
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; Call module constructors
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jsr initlib
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; Check for interruptors
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lda #<__INTERRUPTOR_COUNT__
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beq :+
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; Check for ProDOS
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lda ENTRY
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cmp #$4C ; Is MLI present? (JMP opcode)
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bne :+
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; Allocate interrupt vector table entry
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jsr ENTRY
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.byte $40 ; Alloc interrupt
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.addr params
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; Push arguments and call main()
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: jmp callmain
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; ------------------------------------------------------------------------
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.segment "LOWCODE"
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; ProDOS TechRefMan, chapter 6.2:
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; "Each installed routine must begin with a CLD instruction"
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intrpt: cld
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; Call interruptors
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jsr callirq
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; ProDOS TechRefMan, chapter 6.2:
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; "When the routine that can process the interrupt is called, it
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; should ... return (via an RTS) with the carry flag clear."
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clc
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rts
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; ------------------------------------------------------------------------
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.code
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; Setup RESET vector
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reset: stx SOFTEV
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sta SOFTEV+1
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eor #$A5
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@ -123,10 +159,13 @@ reset: stx SOFTEV
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rts
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; ------------------------------------------------------------------------
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; Data
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.data
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zpsave: .res zpspace
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rvsave: .res 3
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params: .byte $02 ; Parameter count
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intnum: .byte $00 ; Interrupt number
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.addr intrpt ; Interrupt handler
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