From 8ce71f8ab8e49c3f78d7512814c94008a6f4d7a0 Mon Sep 17 00:00:00 2001
From: Adrian Conlon <Adrian.conlon@gmail.com>
Date: Sun, 8 Sep 2019 16:41:04 +0100
Subject: [PATCH] Sync with latest C++ version.  Fixes a couple of Z80 issues.

Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>
---
 Z80/Disassembler.cs |  7 ++++++-
 Z80/Z80.cs          | 46 ++++++++++++++++++++++++---------------------
 2 files changed, 31 insertions(+), 22 deletions(-)

diff --git a/Z80/Disassembler.cs b/Z80/Disassembler.cs
index 7a7c33b..ffd1843 100644
--- a/Z80/Disassembler.cs
+++ b/Z80/Disassembler.cs
@@ -56,7 +56,12 @@ namespace EightBit
                 + $"D={d:x2} E={e:x2} "
                 + $"H={h:x2} L={l:x2} "
                 + $"I={i:x2} R={(byte)r:x2} "
-                + $"IM={im}";
+                + $"IM={im} "
+                + $"IFF1={(cpu.IFF1 ? 1 : 0)} "
+                + $"{(cpu.RESET.Lowered() ? "R" : "-")}"
+                + $"{(cpu.INT.Lowered() ? "I" : "-")}"
+                + $"{(cpu.HALT.Lowered() ? "H" : "-")}"
+                + $"{(cpu.NMI.Lowered() ? "N" : "-")}";
         }
 
         public string Disassemble(Z80 cpu)
diff --git a/Z80/Z80.cs b/Z80/Z80.cs
index 4c06afd..9ad960d 100644
--- a/Z80/Z80.cs
+++ b/Z80/Z80.cs
@@ -193,23 +193,31 @@ namespace EightBit
             {
                 this.displaced = this.prefixCB = this.prefixDD = this.prefixED = false;
                 this.LowerM1();
+                var handled = false;
                 if (this.RESET.Lowered())
                 {
                     this.HandleRESET();
+                    handled = true;
                 }
                 else if (this.NMI.Lowered())
                 {
                     this.HandleNMI();
+                    handled = true;
                 }
                 else if (this.INT.Lowered())
                 {
-                    this.HandleINT();
+                    this.RaiseHALT();
+                    if (handled = this.IFF1)
+                    {
+                        this.HandleINT();
+                    }
                 }
                 else if (this.HALT.Lowered())
                 {
                     this.Execute(0); // NOP
                 }
-                else
+
+                if (!handled)
                 {
                     this.Execute(this.FetchByte());
                 }
@@ -269,26 +277,22 @@ namespace EightBit
         protected override void HandleINT()
         {
             base.HandleINT();
-            this.RaiseHALT();
-            if (this.IFF1)
+            this.DisableInterrupts();
+            switch (this.IM)
             {
-                this.DisableInterrupts();
-                switch (this.IM)
-                {
-                    case 0: // i8080 equivalent
-                        this.Execute(this.Bus.Data);
-                        break;
-                    case 1:
-                        this.Restart(7 << 3);
-                        this.Tick(13);
-                        break;
-                    case 2:
-                        this.Call(this.MEMPTR.Word = new Register16(this.Bus.Data, this.IV).Word);
-                        this.Tick(19);
-                        break;
-                    default:
-                        throw new NotSupportedException("Invalid interrupt mode");
-                }
+                case 0: // i8080 equivalent
+                    this.Execute(this.Bus.Data);
+                    break;
+                case 1:
+                    this.Restart(7 << 3);
+                    this.Tick(13);
+                    break;
+                case 2:
+                    this.Call(this.MEMPTR.Word = new Register16(this.Bus.Data, this.IV).Word);
+                    this.Tick(19);
+                    break;
+                default:
+                    throw new NotSupportedException("Invalid interrupt mode");
             }
         }