From c9fb127730fb19e0c1b084a94f6d1e558b28321e Mon Sep 17 00:00:00 2001
From: EkeEke <ekeeke31@gmail.com>
Date: Fri, 19 Apr 2013 16:55:34 +0200
Subject: [PATCH] fixed 68k interrupt behavior (prevents interrupts from being
 executed multiple time when 68k is halted)

---
 source/m68k/m68kcpu.c | 25 ++++++++++++++-----------
 source/m68k/s68kcpu.c | 22 ++++++++++++++--------
 2 files changed, 28 insertions(+), 19 deletions(-)

diff --git a/source/m68k/m68kcpu.c b/source/m68k/m68kcpu.c
index dd709b1..7c042e1 100644
--- a/source/m68k/m68kcpu.c
+++ b/source/m68k/m68kcpu.c
@@ -205,9 +205,6 @@ void m68k_update_irq(unsigned int mask)
 #ifdef LOGVDP
   error("[%d(%d)][%d(%d)] IRQ Level = %d(0x%02x) (%x)\n", v_counter, m68k.cycles/3420, m68k.cycles, m68k.cycles%3420,CPU_INT_LEVEL>>8,FLAG_INT_MASK,m68k_get_reg(M68K_REG_PC));
 #endif
-
-  /* Check interrupt mask to process IRQ  */
-  m68ki_check_interrupts();
 }
 
 void m68k_set_irq(unsigned int int_level)
@@ -218,9 +215,6 @@ void m68k_set_irq(unsigned int int_level)
 #ifdef LOGVDP
   error("[%d(%d)][%d(%d)] IRQ Level = %d(0x%02x) (%x)\n", v_counter, m68k.cycles/3420, m68k.cycles, m68k.cycles%3420,CPU_INT_LEVEL>>8,FLAG_INT_MASK,m68k_get_reg(M68K_REG_PC));
 #endif
-
-  /* Check interrupt mask to process IRQ  */
-  m68ki_check_interrupts();
 }
 
 /* IRQ latency (Fatal Rewind, Sesame's Street Counting Cafe)*/
@@ -261,6 +255,15 @@ void m68k_set_irq_delay(unsigned int int_level)
 
 void m68k_run(unsigned int cycles) 
 {
+  /* Make sure CPU is not already ahead */
+  if (m68k.cycles >= cycles)
+  {
+    return;
+  }
+
+  /* Check interrupt mask to process IRQ if needed */
+  m68ki_check_interrupts();
+
   /* Make sure we're not stopped */
   if (CPU_STOPPED)
   {
@@ -268,12 +271,12 @@ void m68k_run(unsigned int cycles)
     return;
   }
 
-  /* Return point for when we have an address error (TODO: use goto) */
-  m68ki_set_address_error_trap() /* auto-disable (see m68kcpu.h) */
-
   /* Save end cycles count for when CPU is stopped */
   m68k.cycle_end = cycles;
 
+  /* Return point for when we have an address error (TODO: use goto) */
+  m68ki_set_address_error_trap() /* auto-disable (see m68kcpu.h) */
+
 #ifdef LOGVDP
   error("[%d][%d] m68k run to %d cycles (%x)\n", v_counter, m68k.cycles, cycles, m68k.pc);
 #endif
@@ -290,8 +293,8 @@ void m68k_run(unsigned int cycles)
     REG_IR = m68ki_read_imm_16();
 	
     /* Execute instruction */
-	  m68ki_instruction_jump_table[REG_IR](); /* TODO: use labels table with goto */
-    USE_CYCLES(CYC_INSTRUCTION[REG_IR]); /* TODO: move into instruction handlers */
+	m68ki_instruction_jump_table[REG_IR]();
+    USE_CYCLES(CYC_INSTRUCTION[REG_IR]);
 
     /* Trace m68k_exception, if necessary */
     m68ki_exception_if_trace(); /* auto-disable (see m68kcpu.h) */
diff --git a/source/m68k/s68kcpu.c b/source/m68k/s68kcpu.c
index 4fe7312..40ff145 100644
--- a/source/m68k/s68kcpu.c
+++ b/source/m68k/s68kcpu.c
@@ -215,13 +215,19 @@ void s68k_update_irq(unsigned int mask)
 #ifdef LOG_SCD
   error("[%d][%d] IRQ Level = %d(0x%02x) (%x)\n", v_counter, s68k.cycles, CPU_INT_LEVEL>>8,FLAG_INT_MASK,s68k.pc);
 #endif
-
-  /* Check interrupt mask to process IRQ  */
-  m68ki_check_interrupts();
 }
 
 void s68k_run(unsigned int cycles) 
 {
+  /* Make sure CPU is not already ahead */
+  if (s68k.cycles >= cycles)
+  {
+    return;
+  }
+
+  /* Check interrupt mask to process IRQ if needed */
+  m68ki_check_interrupts();
+
   /* Make sure we're not stopped */
   if (CPU_STOPPED)
   {
@@ -229,11 +235,12 @@ void s68k_run(unsigned int cycles)
     return;
   }
 
+  /* Save end cycles count for when CPU is stopped */
+  s68k.cycle_end = cycles;
+
   /* Return point for when we have an address error (TODO: use goto) */
   m68ki_set_address_error_trap() /* auto-disable (see m68kcpu.h) */
 
-  /* Save end cycles count for when CPU is stopped */
-  s68k.cycle_end = cycles;
 #ifdef LOG_SCD
   error("[%d][%d] s68k run to %d cycles (%x), irq mask = %x (%x)\n", v_counter, s68k.cycles, cycles, s68k.pc,FLAG_INT_MASK, CPU_INT_LEVEL);
 #endif
@@ -249,10 +256,9 @@ void s68k_run(unsigned int cycles)
     /* Decode next instruction */
     REG_IR = m68ki_read_imm_16();
 
-	
     /* Execute instruction */
-	  m68ki_instruction_jump_table[REG_IR](); /* TODO: use labels table with goto */
-    USE_CYCLES(CYC_INSTRUCTION[REG_IR]); /* TODO: move into instruction handlers */
+	m68ki_instruction_jump_table[REG_IR]();
+    USE_CYCLES(CYC_INSTRUCTION[REG_IR]);
 
     /* Trace m68k_exception, if necessary */
     m68ki_exception_if_trace(); /* auto-disable (see m68kcpu.h) */