44 lines
687 B
ArmAsm
44 lines
687 B
ArmAsm
// #LAYOUT# STD * #TAKE
|
|
// #LAYOUT# * KERNAL_0 #TAKE
|
|
// #LAYOUT# * * #IGNORE
|
|
|
|
//
|
|
// RS-232 IRQ handler part
|
|
//
|
|
|
|
// Based on UP9600 code by Daniel Dallman with Bo Zimmerman adaptations
|
|
|
|
|
|
#if CONFIG_RS232_UP9600
|
|
|
|
|
|
up9600_irq:
|
|
|
|
lda CIA1_ICR // $DC0D
|
|
|
|
lsr
|
|
lsr // move bit 1 (timer B flag) into Carry
|
|
and #$02 // test SDR (shift register) status
|
|
|
|
beq up9600_irq_continue
|
|
|
|
ldx RINONE
|
|
beq !+ // skip if not waiting for empty SDR
|
|
dex
|
|
stx RINONE
|
|
!:
|
|
bcc up9600_irq_end
|
|
|
|
up9600_irq_continue:
|
|
|
|
rts
|
|
|
|
up9600_irq_end:
|
|
|
|
pla
|
|
pla
|
|
jmp return_from_interrupt
|
|
|
|
|
|
#endif // CONFIG_RS232_UP9600
|