From 393b28ab3d33b87a6bd900e55505a7202ba31623 Mon Sep 17 00:00:00 2001
From: tudnai <tamas.rudnai@gmail.com>
Date: Sat, 2 May 2020 22:35:59 -0700
Subject: [PATCH] Interrupt handling outside of the instruction loop

---
 A2Mac/ViewController.swift | 10 +++++++
 src/cpu/6502.c             | 56 ++++++++++++++++++++++++--------------
 src/cpu/6502.h             |  7 +++--
 3 files changed, 50 insertions(+), 23 deletions(-)

diff --git a/A2Mac/ViewController.swift b/A2Mac/ViewController.swift
index 3cde6a4..6e5d4b2 100644
--- a/A2Mac/ViewController.swift
+++ b/A2Mac/ViewController.swift
@@ -141,6 +141,16 @@ class ViewController: NSViewController  {
 //        m6502.pc = resetAddr
         
         m6502.interrupt = SOFTRESET;
+        
+        let saved_frm_set = clk_6502_per_frm_set;
+        clk_6502_per_frm_set = 0
+        clk_6502_per_frm_max = 0
+        // wait for 1 ms to allow the simulation to halt
+        usleep(10000);
+
+        softReset()
+     
+        clk_6502_per_frm_set = saved_frm_set
     }
     
     
diff --git a/src/cpu/6502.c b/src/cpu/6502.c
index 9177aa6..1896f2d 100644
--- a/src/cpu/6502.c
+++ b/src/cpu/6502.c
@@ -131,7 +131,6 @@ typedef struct {
  This idea is that "INLINE" would work only if it is
  located in the same source file -- hence the include...
 **/
-#include "6502_instructions.h"
 
 INLINE flags_t getFlags() {
     flags_t f = {
@@ -162,6 +161,7 @@ INLINE void setFlags( uint8_t byte ) {
     m6502.N = flags.N;      // Negative Flag
 }
 
+#include "6502_instructions.h"
 
 INLINE int m6502_Step() {
 
@@ -672,6 +672,36 @@ unsigned long long epoch = 0;
 
 unsigned int clkfrm = 0;
 
+void interrupt_IRQ() {
+    m6502.PC = memread16(IRQ_VECTOR);
+    // TODO: PUSH things onto stack?
+}
+
+void interrupt_NMI() {
+    m6502.PC = memread16(NMI_VECTOR);
+    // TODO: PUSH things onto stack?
+}
+
+void hardReset() {
+    m6502.PC = memread16(RESET_VECTOR);
+    // make sure it will be a cold reset...
+    memwrite(0x3F4, 0);
+    m6502.SP = 0xFF;
+    // N V - B D I Z C
+    // 0 0 1 0 0 1 0 1
+    setFlags(0x25);
+}
+
+void softReset() {
+//    m6502.PC = memread16(SOFTRESET_VECTOR);
+    m6502.PC = memread16( RESET_VECTOR );
+    
+    m6502.SP = 0xFF;
+    // N V - B D I Z C
+    // 0 0 1 0 0 1 0 1
+    setFlags(0x25);
+}
+
 void m6502_Run() {
     static unsigned int clk = 0;
     
@@ -702,35 +732,19 @@ void m6502_Run() {
                     return;
                     
                 case IRQ:
-                    m6502.PC = memread16(IRQ_VECTOR);
-                    // TODO: PUSH things onto stack?
+                    interrupt_IRQ();
                     break;
                     
                 case NMI:
-                    m6502.PC = memread16(NMI_VECTOR);
-                    // TODO: PUSH things onto stack?
+                    interrupt_NMI();
                     break;
                     
                 case HARDRESET:
-                    m6502.PC = memread16(RESET_VECTOR);
-                    // make sure it will be a cold reset...
-                    memwrite(0x3F4, 0);
-                    m6502.SP = 0xFF;
-                    // N V - B D I Z C
-                    // 0 0 1 0 0 1 0 1
-                    m6502.SR = 0x25;
-                    
+                    hardReset();
                     break;
                     
                 case SOFTRESET:
-//                    m6502.PC = memread16(SOFTRESET_VECTOR);
-                    m6502.PC = memread16( RESET_VECTOR );
-
-                    m6502.SP = 0xFF;
-                    // N V - B D I Z C
-                    // 0 0 1 0 0 1 0 1
-                    m6502.SR = 0x25;
-
+                    softReset();
                     break;
                     
                 default:
diff --git a/src/cpu/6502.h b/src/cpu/6502.h
index 9bfd472..55ebbd8 100644
--- a/src/cpu/6502.h
+++ b/src/cpu/6502.h
@@ -161,7 +161,10 @@ extern void m6502_Run(void);
 extern void kbdInput ( uint8_t code );
 extern void setIO ( uint16_t ioaddr, uint8_t val );
 
-INLINE flags_t getFlags( void );
-INLINE void setFlags( uint8_t byte );
+extern void interrupt_IRQ(void);
+extern void interrupt_NMI(void);
+extern void hardReset(void);
+extern void softReset(void);
+
 
 #endif /* __6502_H__ */