WIP check interrupts

snes-core/src/cpu/interface.rs

@@ -34,9 +34,9 @@ impl CPU {
             return false;
         }
         if self.registers.is_cpu_waiting_interrupt {
-            // TODO: check for interrupts here
-            let (bytes, cycles) = cycles::increment_cycles_while_stopped();
-            self.registers.increment_pc(bytes); self.registers.cycles += cycles;
+            self.check_interrupts(bus);
+            let (_, cycles) = cycles::increment_cycles_while_stopped();
+            self.registers.cycles += cycles;
             return false;
         }
         if self.registers.is_moving {

snes-core/src/cpu/vectors.rs

@@ -1,4 +1,4 @@
-use super::{interface::CPU, instructions::{phk::PHK, CPUInstruction, php::PHP, push_common}};
+use super::{instructions::{phk::PHK, php::PHP, push_common, CPUInstruction}, interface::CPU, internal_registers::RDNMI};
 use crate::cpu::bus::Bus;
 
 
@@ -38,13 +38,6 @@ impl CPU {
         self.registers.is_cpu_stopped = false;
     }
 
-    fn get_vector_from_interrupts(&self) -> Option<Vector> {
-        if self.registers.get_irq_disable_flag() {
-            return None;
-        }
-        Some(Vector::Reset)
-    }
-
     fn push_emulation_interrupt(&mut self, bus: &mut Bus) {
         if !self.registers.emulation_mode {
             PHK{}.execute(&mut self.registers, bus);
@@ -57,14 +50,22 @@ impl CPU {
         PHP{}.execute(&mut self.registers, bus);
     }
 
-    pub fn handle_interrupts(&mut self, bus: &mut Bus) {
+    fn handle_interrupt(&mut self, bus: &mut Bus, vector: Vector) {
         self.push_emulation_interrupt(bus);
-        if let Some(vector) = self.get_vector_from_interrupts() {
         let effective_vector = vector.get_base_address();
         self.registers.pc = effective_vector as u16;
         self.registers.pbr = (effective_vector >> 16) as u8;
     }
+
+    pub fn check_interrupts(&mut self, bus: &mut Bus) {
+        let rdnmi_byte = bus.read(RDNMI as u32);
+        if rdnmi_byte >> 7 != 0 {
+            self.registers.is_cpu_waiting_interrupt = false;
+            self.handle_interrupt(bus, Vector::NMI);
+            return;
         }
+    }
+
 }
 
 

snes-core/src/ppu/interface.rs

@@ -3,6 +3,7 @@ use super::registers::PPURegisters;
 pub struct PPU {
     framebuffer: Vec<u8>,
     pub registers: PPURegisters,
+    was_vblank_nmi_set: bool,
 }
 
 impl PPU {
@@ -10,6 +11,7 @@ impl PPU {
         Self {
             framebuffer: vec![],
             registers: PPURegisters::new(),
+            was_vblank_nmi_set: false,
         }
     }
 
@@ -28,10 +30,12 @@ impl PPU {
         if self.registers.h_count > 339 {
             self.registers.h_count = 0;
             self.registers.v_count += 1;
-            if self.registers.v_count > 224 {
+            if self.registers.v_count > 224 && !self.was_vblank_nmi_set {
                 self.registers.vblank_nmi = true;
+                self.was_vblank_nmi_set = true;
             }
             if self.registers.v_count > 261 {
+                self.was_vblank_nmi_set = false;
                 self.registers.v_count = 0;
             }
         }