Added flag to disable DOS delay code

apple2.go

@@ -23,6 +23,7 @@ import (
 var (
 	showInstructions    *bool   // Display all instructions as they are executed
 	disableFirmwareWait *bool   // Disable the WAIT function at $fca8
+	disableDosDelay     *bool   // Disable DOS delay functions
 	breakAddress        *uint16 // Break address from the command line
 
 	resetKeysDown bool // Keep track of ctrl-alt-R key down state
@@ -65,7 +66,7 @@ func update(screen *ebiten.Image) error {
 	exitAtBreak := true        // Die if a BRK instruction is seen
 
 	// Run for 1/60 of a second, the duration of an ebiten frame
-	cpu.Run(*showInstructions, breakAddress, exitAtBreak, *disableFirmwareWait, system.CPUFrequency/60)
+	cpu.Run(*showInstructions, breakAddress, exitAtBreak, *disableFirmwareWait, *disableDosDelay, system.CPUFrequency/60)
 
 	// Process any audio speaker clicks from this frame
 	audio.ForwardToFrameCycle()
@@ -88,6 +89,7 @@ func main() {
 
 	showInstructions = flag.Bool("show-instructions", false, "Show instructions code while running")
 	disableFirmwareWait = flag.Bool("disable-wait", false, "Ignore JSRs to firmware wait at $FCA8")
+	disableDosDelay = flag.Bool("disable-dos-delay", false, "Ignore DOS ARM move and motor on waits")
 	breakAddressString := flag.String("break", "", "Break on address")
 	mute := flag.Bool("mute", false, "Mute sound")
 	clickWhenDriveHeadMoves := flag.Bool("drive-head-click", false, "Click speaker when drive head moves")

bell_test.go

@@ -23,8 +23,9 @@ func testBellCycles(delay int) {
 	breakAddress := uint16(0x805)
 	exitAtBreak := false
 	disableFirmwareWait := false
+	disableDosDelay := false
 	cpu.State.PC = 0x800
-	cpu.Run(showInstructions, &breakAddress, exitAtBreak, disableFirmwareWait, system.CPUFrequency*1000)
+	cpu.Run(showInstructions, &breakAddress, exitAtBreak, disableFirmwareWait, disableDosDelay, system.CPUFrequency*1000)
 
 	// See http://apple2.org.za/gswv/a2zine/GS.WorldView/Resources/USEFUL.TABLES/WAIT.DELAY.CR.txt
 	expectedCycles := (26 + 27*delay + 5*delay*delay) / 2

cpu/cpu.go

@@ -551,7 +551,7 @@ func nmi() {
 
 // Run runs the CPU until either wantedCycles has been reached (if non-zero) or the program counter reaches breakAddress.
 // system.FrameCycles is the amount of cycles executed so far.
-func Run(showInstructions bool, breakAddress *uint16, exitAtBreak bool, disableFirmwareWait bool, wantedCycles uint64) {
+func Run(showInstructions bool, breakAddress *uint16, exitAtBreak bool, disableFirmwareWait bool, disableDosDelay bool, wantedCycles uint64) {
 	system.FrameCycles = 0
 
 	for {
@@ -632,6 +632,10 @@ func Run(showInstructions bool, breakAddress *uint16, exitAtBreak bool, disableF
 				State.PC += 3
 				State.A = 0
 				continue
+			} else if disableDosDelay && value == 0xba00 {
+				// Don't call the delay, just move forward and pretend it happened.
+				State.PC += 3
+				continue
 			}
 
 			push16(State.PC + 2)
@@ -647,6 +651,15 @@ func Run(showInstructions bool, breakAddress *uint16, exitAtBreak bool, disableF
 		case 0xa2, 0xa6, 0xb6, 0xae, 0xbe: // LDX
 			State.X = load(addressMode)
 		case 0xa0, 0xa4, 0xb4, 0xac, 0xbc: // LDY
+			if disableDosDelay {
+				pc := uint16(mmu.ReadMemory(State.PC+1)) + uint16(mmu.ReadMemory(State.PC+2))<<8
+				if pc == 0xbd9e {
+					// Don't do delay, just move forward and pretend it happened.
+					State.PC += 13
+					continue
+				}
+			}
+
 			State.Y = load(addressMode)
 
 		case 0x85, 0x95, 0x8d, 0x9d, 0x99, 0x81, 0x91: //STA

cpu/cpu_test.go

@@ -76,7 +76,7 @@ func TestCPU(t *testing.T) {
 			mmu.WritePageTable[0xc0+i] = RomPretendingToBeRAM[i*0x100 : i*0x100+0x100]
 		}
 
-		cpu.Run(*showInstructions, breakAddress, true, false, 0)
+		cpu.Run(*showInstructions, breakAddress, true, false, false, 0)
 		fmt.Printf("Finished running %s\n\n", rom)
 	}
 }

utils/utils.go

@@ -60,7 +60,8 @@ func RunUntilBreakPoint(t *testing.T, breakAddress uint16, seconds int, showInst
 	system.LastAudioCycles = 0
 	exitAtBreak := false
 	disableFirmwareWait := false
-	cpu.Run(showInstructions, &breakAddress, exitAtBreak, disableFirmwareWait, uint64(system.CPUFrequency*seconds))
+	disableDosDelay := false
+	cpu.Run(showInstructions, &breakAddress, exitAtBreak, disableFirmwareWait, disableDosDelay, uint64(system.CPUFrequency*seconds))
 	if cpu.State.PC != breakAddress {
 		t.Fatalf("Did not reach breakpoint at %04x. Got to %04x", breakAddress, cpu.State.PC)
 	}