Implement interrupt status register

Upon an interrupt, you can read from the interrupt status register to see what caused the interrupt.
2022-03-14 13:30:01 -05:00
parent e012eb7d4d
commit a5474b5ae5
5 changed files with 46 additions and 1 deletions
--- a/sw/interrupt.s
+++ b/sw/interrupt.s
@@ -9,6 +9,9 @@
 .import   _handle_irq

 .export   _irq_int, _nmi_int
+.export   _irq_get_status
+
+.include "io.inc65"

 .segment  "CODE"

@@ -43,4 +46,9 @@ irq:       PLA                    ; Restore accumulator contents
 ; BRK detected, stop

 break:     JMP break              ; If BRK is detected, something very bad
-                                  ;   has happened, so stop running
+                                  ;   has happened, so stop running
+
+_irq_get_status:
+           lda IRQ_STATUS
+           ldx #$00
+           rts