mirror of
https://github.com/cc65/cc65.git
synced 2024-12-24 11:31:31 +00:00
101 lines
2.1 KiB
ArmAsm
101 lines
2.1 KiB
ArmAsm
|
;
|
||
|
|
; Ullrich von Bassewitz, 28.09.1998
|
||
|
|
;
|
||
|
|
; IRQ routine for the 610.
|
||
|
|
;
|
||
|
|
|
||
|
|
.export irq, nmi, k_irq, k_nmi
|
||
|
|
.import k_scnkey, k_udtim, k_rs232
|
||
|
|
.importzp tpi1
|
||
|
|
|
||
|
|
.include "zeropage.inc"
|
||
|
|
.include "io.inc"
|
||
|
|
.include "page3.inc"
|
||
|
|
|
||
|
|
|
||
|
|
; -------------------------------------------------------------------------
|
||
|
|
; This is the mapping of the active irq register of the 6525 (tpi1):
|
||
|
|
;
|
||
|
|
; Bit 7 6 5 4 3 2 1 0
|
||
|
|
; | | | | ^ 50 Hz
|
||
|
|
; | | | ^ SRQ IEEE 488
|
||
|
|
; | | ^ cia
|
||
|
|
; | ^ IRQB ext. Port
|
||
|
|
; ^ acia
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
; -------------------------------------------------------------------------
|
||
|
|
; IRQ entry point
|
||
|
|
|
||
|
|
.proc irq
|
||
|
|
|
||
|
|
pha
|
||
|
|
txa
|
||
|
|
pha
|
||
|
|
tya
|
||
|
|
pha
|
||
|
|
tsx
|
||
|
|
lda $104,x ; Get the flags from the stack
|
||
|
|
and #$10 ; Test break flag
|
||
|
|
bne L1
|
||
|
|
jmp (IRQVec)
|
||
|
|
L1: jmp (BRKVec)
|
||
|
|
|
||
|
|
.endproc
|
||
|
|
|
||
|
|
; -------------------------------------------------------------------------
|
||
|
|
; NMI entry point
|
||
|
|
|
||
|
|
.proc nmi
|
||
|
|
|
||
|
|
jmp (NMIVec)
|
||
|
|
|
||
|
|
.endproc
|
||
|
|
|
||
|
|
|
||
|
|
; -------------------------------------------------------------------------
|
||
|
|
; Kernal irq entry point. The IRQvec points here (usually).
|
||
|
|
|
||
|
|
k_irq:
|
||
|
|
lda IndReg ; Ind. Segment retten
|
||
|
|
pha
|
||
|
|
cld
|
||
|
|
lda #$0F
|
||
|
|
sta IndReg
|
||
|
|
ldy #tpiActIntReg
|
||
|
|
lda (tpi1),y ; Interrupt Register 6525
|
||
|
|
beq noirq
|
||
|
|
|
||
|
|
; -------------------------------------------------------------------------
|
||
|
|
; 50/60Hz interrupt
|
||
|
|
|
||
|
|
cmp #%00000001 ; ticker irq?
|
||
|
|
bne irq1
|
||
|
|
jsr k_scnkey ; Poll the keyboard
|
||
|
|
jsr k_udtim ; Bump the time
|
||
|
|
|
||
|
|
; -------------------------------------------------------------------------
|
||
|
|
; UART interrupt
|
||
|
|
|
||
|
|
irq1: cmp #%00010000 ; interrupt from uart?
|
||
|
|
bne irqend
|
||
|
|
jsr k_rs232 ; Read character from uart
|
||
|
|
|
||
|
|
; -------------------------------------------------------------------------
|
||
|
|
; Done
|
||
|
|
|
||
|
|
irqend: ldy #tpiActIntReg
|
||
|
|
sta (tpi1),y ; Clear interrupt
|
||
|
|
|
||
|
|
noirq: pla
|
||
|
|
sta IndReg
|
||
|
|
pla
|
||
|
|
tay
|
||
|
|
pla
|
||
|
|
tax
|
||
|
|
pla
|
||
|
|
k_nmi: rti
|
||
|
|
|
||
|
|
|