static VOID XmsLocalDisableA20(VOID)
{
UCHAR Result = XMS_STATUS_SUCCESS;
/* Disable A20 only if we can do so, otherwise make the caller believe we disabled it */
if (!CanChangeA20) goto Quit;
/* If the count is already zero, fail */
if (A20EnableCount == 0) goto Fail;
--A20EnableCount;
/* The count is zero so disable A20 */
if (A20EnableCount == 0)
EmulatorSetA20(FALSE); // Result = XMS_STATUS_SUCCESS;
else
Result = XMS_STATUS_A20_STILL_ENABLED;
Quit:
setAX(0x0001); /* Line successfully disabled */
setBL(Result);
return;
Fail:
setAX(0x0000); /* Line failed to be disabled */
setBL(XMS_STATUS_A20_ERROR);
return;
}
static VOID XmsLocalEnableA20(VOID)
{
/* Enable A20 only if we can do so, otherwise make the caller believe we enabled it */
if (!CanChangeA20) goto Quit;
/* The count is zero so enable A20 */
if (A20EnableCount == 0) EmulatorSetA20(TRUE);
++A20EnableCount;
Quit:
setAX(0x0001); /* Line successfully enabled */
setBL(XMS_STATUS_SUCCESS);
return;
}
static VOID WINAPI PS2WritePort(ULONG Port, BYTE Data)
{
if (Port == PS2_CONTROL_PORT)
{
switch (Data)
{
/* Read configuration byte */
case 0x20:
{
OutputBuffer = ControllerConfig;
StatusRegister |= (1 << 0); // There is something to read
break;
}
/* Write configuration byte */
case 0x60:
/* Write controller output port */
case 0xD1:
/* Write to the first PS/2 port output buffer */
case 0xD2:
/* Write to the second PS/2 port output buffer */
case 0xD3:
/* Write to the second PS/2 port input buffer */
case 0xD4:
{
/* These commands require a response */
ControllerCommand = Data;
StatusRegister |= (1 << 3); // This is a controller command
break;
}
/* Disable second PS/2 port */
case 0xA7:
{
Ports[1].IsEnabled = FALSE;
break;
}
/* Enable second PS/2 port */
case 0xA8:
{
Ports[1].IsEnabled = TRUE;
break;
}
/* Test second PS/2 port */
case 0xA9:
{
OutputBuffer = 0x00; // Success code
StatusRegister |= (1 << 0); // There is something to read
break;
}
/* Test PS/2 controller */
case 0xAA:
{
OutputBuffer = 0x55; // Success code
StatusRegister |= (1 << 0); // There is something to read
break;
}
/* Test first PS/2 port */
case 0xAB:
{
OutputBuffer = 0x00; // Success code
StatusRegister |= (1 << 0); // There is something to read
break;
}
/* Disable first PS/2 port */
case 0xAD:
{
Ports[0].IsEnabled = FALSE;
break;
}
/* Enable first PS/2 port */
case 0xAE:
{
Ports[0].IsEnabled = TRUE;
break;
}
/* Read controller output port */
case 0xD0:
{
// TODO: Not implemented
break;
}
/* CPU Reset */
case 0xF0:
case 0xF2:
case 0xF4:
case 0xF6:
case 0xF8:
case 0xFA:
case 0xFC:
case 0xFE:
{
/* Stop the VDM */
EmulatorTerminate();
break;
}
}
}
else if (Port == PS2_DATA_PORT)
{
/* Check if the controller is waiting for a response */
if (StatusRegister & (1 << 3)) // If we have data for the controller
{
StatusRegister &= ~(1 << 3);
/* Check which command it was */
switch (ControllerCommand)
{
/* Write configuration byte */
case 0x60:
{
ControllerConfig = Data;
break;
}
/* Write controller output */
case 0xD1:
{
/* Check if bit 0 is unset */
if (!(Data & (1 << 0)))
{
/* CPU disabled - Stop the VDM */
EmulatorTerminate();
}
/* Update the A20 line setting */
EmulatorSetA20(Data & (1 << 1));
break;
}
/* Push the data byte into the first PS/2 port queue */
case 0xD2:
{
PS2QueuePush(0, Data);
break;
}
/* Push the data byte into the second PS/2 port queue */
case 0xD3:
{
PS2QueuePush(1, Data);
break;
}
/*
* Send a command to the second PS/2 port (by default
* it is a command for the first PS/2 port)
*/
case 0xD4:
{
PS2SendCommand(&Ports[1], Data);
break;
}
}
return;
}
/* By default, send a command to the first PS/2 port */
PS2SendCommand(&Ports[0], Data);
}
}
