wip: irq

system/irq_handler.h65

@@ -0,0 +1,12 @@
+;********************************************************************************
+; @module irq_handler
+; @type system
+;********************************************************************************
+.ifndef INCLUDE_IRQ_HANDLER
+INCLUDE_IRQ_HANDLER = 1
+
+.scope irq
+
+.endscope
+.endif
+

system/irq_handler.s65

@@ -0,0 +1,43 @@
+.include "irq_handler.h65"
+.bss
+
+
+.code
+
+.proc register_via_handler
+.endproc
+
+.proc remove_via_handler
+.endproc
+
+.proc main_handler
+    Print "Unknown IRQ"
+    rti
+.endproc
+
+.zeropage
+tmp: .res 1
+
+.macro VIAHandler via_addr, via_handlers_table
+    lda via_addr + IO::IFR
+    sta tmp
+    bbr7 tmp,@rts  ; irq
+    bbs0 tmp,@ca2
+    bbs1 tmp,@ca1
+    bbs2 tmp,@sr
+    bbs3 tmp,@cb2
+    bbs4 tmp,@cb1
+    bbs5 tmp,@t2
+    bbs6 tmp,@t1
+    ; TODO error, one should have been true
+    stp
+@rts:
+    rts
+@ca2:   jmp (via_handlers_table)
+@ca1:   jmp (via_handlers_table+2)
+@sr:    jmp (via_handlers_table+4)
+@cb2:   jmp (via_handlers_table+6)
+@cb1:   jmp (via_handlers_table+8)
+@t2:    jmp (via_handlers_table+10)
+@t1:    jmp (via_handlers_table+12)
+.endmacro