fix: OPL3 port read delay and remove legacy ASM tests

Simulate 1.5us hardware latency in Opl3Fm port reads. Add Opl3WriteDelayTest to verify timing. Remove OplIntegrationTests and related ASM source/binary files. Minor: add unused usings in IOPortDispatcher.cs.

Author: maximilien-noal

src/Spice86.Core/Emulator/Devices/Sound/Opl3Fm.cs

@@ -178,6 +178,10 @@ public override byte ReadByte(ushort port) {
     }
 
     private byte PortRead(ushort port) {
+        // Roughly half a microsecond
+        // and some tests revealed it taking 1.5us to read an AdLib port.
+        double currentTime = _clock.ElapsedTimeMs;
+        SpinWait.SpinUntil(() => TimeSpan.FromMilliseconds(_clock.ElapsedTimeMs - currentTime) >= TimeSpan.FromMicroseconds(1.5));
         switch (_mode) {
             case OplMode.Opl2:
                 // We allocated 4 ports, so just return -1 for the higher ones.

tests/Spice86.Tests/Emulator/Devices/Sound/Opl3WriteDelayTest.cs

@@ -0,0 +1,42 @@
+namespace Spice86.Tests.Emulator.Devices.Sound;
+
+using FluentAssertions;
+
+using NSubstitute;
+
+using Spice86.Core.Emulator.CPU;
+using Spice86.Core.Emulator.Devices.Sound;
+using Spice86.Core.Emulator.VM;
+using Spice86.Core.Emulator.VM.Clock;
+using Spice86.Shared.Interfaces;
+
+using System;
+
+using Xunit;
+
+[Trait("Category", "Sound")]
+public class Opl3WriteDelayTest {
+
+    [Fact]
+    public void Opl3ReadDelayIsAMicroSecondAndAHalf() {
+        //Arrange
+        State state = new(CpuModel.INTEL_80386);
+        ILoggerService loggerService = Substitute.For<ILoggerService>();
+        Opl3Fm opl3fm = new(new(OplMode.Opl3, 0x220, SbMixer: true),
+            new SoftwareMixer(Audio.Filters.AudioEngine.Dummy,
+            new PauseHandler(loggerService)),
+            state,
+            new EmulatedClock(null, DateTimeOffset.Now),
+            new Core.Emulator.IOPorts.IOPortDispatcher(new(), state, loggerService, false),
+            false,
+            loggerService);
+
+        //Act
+        DateTime before = DateTime.Now;
+        _ = opl3fm.ReadByte(0x330);
+        DateTime after = DateTime.Now;
+
+        //Assert
+        (after - before).Should().BeGreaterThanOrEqualTo(TimeSpan.FromMicroseconds(1.5));
+    }
+}