From 496f63acdc6b7183562ed5dc14efa2b070dd201b Mon Sep 17 00:00:00 2001
From: infiton <kbt.tate@gmail.com>
Date: Wed, 13 Jul 2022 12:27:10 -0400
Subject: [PATCH] allow for interrupts

---
 ext/ruby6502/fake6502.c | 10 ++++++----
 ext/ruby6502/fake6502.h |  2 ++
 ext/ruby6502/ruby6502.c | 14 ++++++++++++++
 3 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/ext/ruby6502/fake6502.c b/ext/ruby6502/fake6502.c
index dd0170e..b2bea6a 100644
--- a/ext/ruby6502/fake6502.c
+++ b/ext/ruby6502/fake6502.c
@@ -960,10 +960,12 @@ void nmi6502() {
 }
 
 void irq6502() {
-    push16(pc);
-    push8(status);
-    status |= FLAG_INTERRUPT;
-    pc = (uint16_t)read6502(0xFFFE) | ((uint16_t)read6502(0xFFFF) << 8);
+    if (! (status & FLAG_INTERRUPT) ) {
+        push16(pc);
+        push8(status);
+        status |= FLAG_INTERRUPT;
+        pc = (uint16_t)read6502(0xFFFE) | ((uint16_t)read6502(0xFFFF) << 8);
+    }
 }
 
 uint8_t callexternal = 0;
diff --git a/ext/ruby6502/fake6502.h b/ext/ruby6502/fake6502.h
index 1c4c8cd..54a1c19 100644
--- a/ext/ruby6502/fake6502.h
+++ b/ext/ruby6502/fake6502.h
@@ -4,6 +4,8 @@
 void reset6502();
 void step6502();
 void exec6502(uint32_t tickcount);
+void nmi6502();
+void irq6502();
 void hookexternal(void *funcptr);
 
 uint16_t getPC();
diff --git a/ext/ruby6502/ruby6502.c b/ext/ruby6502/ruby6502.c
index 85eeb6c..6127732 100644
--- a/ext/ruby6502/ruby6502.c
+++ b/ext/ruby6502/ruby6502.c
@@ -46,6 +46,18 @@ static VALUE reset(VALUE self)
   return Qtrue;
 }
 
+static VALUE interrupt_request(VALUE self)
+{
+  irq6502();
+  return Qtrue;
+}
+
+static VALUE non_maskable_interrupt(VALUE self)
+{
+  nmi6502();
+  return Qtrue;
+}
+
 static VALUE step(VALUE self)
 {
   step6502();
@@ -117,6 +129,8 @@ void Init_ruby6502()
   rb_define_singleton_method(mRuby6502, "hooks?", get_has_hooks, 0);
 
   rb_define_singleton_method(mRuby6502, "reset", reset, 0);
+  rb_define_singleton_method(mRuby6502, "interrupt_request", interrupt_request, 0);
+  rb_define_singleton_method(mRuby6502, "non_maskable_interrupt", non_maskable_interrupt, 0);
   rb_define_singleton_method(mRuby6502, "step", step, 0);
   rb_define_singleton_method(mRuby6502, "exec", exec, 1);