Applecorn/mainmem.init.s
2022-12-22 18:26:50 -05:00

52 lines
1.6 KiB
ArmAsm

* MAINMEM.INIT.S
* (c) Bobbi 2021 GPLv3
*
* Initialization, interrupt handling and reset handling code
* that resides in main memory.
* 14-Nov-2021 If started from CSD, gets prefix to CMDBUF.
AUDIOCARD DB $00 ; $00 = Mockingboard, $01 = Ensoniq
* Trampoline in main memory used by aux memory IRQ handler
* to invoke Apple II / ProDOS IRQs in main memory
A2IRQ >>> IENTMAIN ; IENTMAIN does not do CLI
LDA #>A2IRQRET
PHA
LDA #<A2IRQRET
PHA
PHP ; Fake things to look like IRQ
JMP (A2IRQV) ; Call Apple II ProDOS ISR
A2IRQRET >>> XF2AUX,IRQBRKRET
* BRK handler in main memory. Used on Apple IIgs only.
GSBRK >>> XF2AUX,GSBRKAUX
* Reset handler - invoked on Ctrl-Reset
* XFER to AUXMOS ($D000) in aux, AuxZP on, LC on
RESET TSX
STX $0100
LDA AN0OFF ; AN0 off
LDA AN1OFF ; AN1 off
LDA AN2ON ; AN2 on
LDA AN3ON ; AN3 on
JSR RESETHW ; Reset hardware
>>> XF2AUX,AUXMOS
* Reset hardware
RESETHW SEC
STZ AUDIOCARD
JSR IDROUTINE ; See if this is a GS
BCS :NOTGS
JSR ENSQINIT ; Initialize Ensoniq
INC AUDIOCARD
RTS ; AUDIOCARD=1
:NOTGS
JSR MOCKINIT ; Initialize Mockingboard (sl4)
RTSINSTR RTS ; AUDIOCARD=0