reactos/subsystems/ntvdm/ps2.c

/*
 * COPYRIGHT:       GPL - See COPYING in the top level directory
 * PROJECT:         ReactOS Virtual DOS Machine
 * FILE:            ps2.c
 * PURPOSE:         PS/2 controller emulation
 * PROGRAMMERS:     Aleksandar Andrejevic <theflash AT sdf DOT lonestar DOT org>
 */

/* INCLUDES *******************************************************************/

#include "ps2.h"
#include "emulator.h"
#include "pic.h"

/* PRIVATE VARIABLES **********************************************************/

static BYTE KeyboardQueue[KEYBOARD_BUFFER_SIZE];
static BOOLEAN KeyboardQueueEmpty = TRUE;
static UINT KeyboardQueueStart = 0;
static UINT KeyboardQueueEnd = 0;
static BYTE KeyboardResponse = 0;
static BOOLEAN KeyboardReadResponse = FALSE, KeyboardWriteResponse = FALSE;
static BYTE KeyboardConfig = PS2_DEFAULT_CONFIG;

/* PRIVATE FUNCTIONS **********************************************************/

static BOOLEAN KeyboardQueuePush(BYTE ScanCode)
{
    /* Check if the keyboard queue is full */
    if (!KeyboardQueueEmpty && (KeyboardQueueStart == KeyboardQueueEnd))
    {
        return FALSE;
    }

    /* Insert the value in the queue */
    KeyboardQueue[KeyboardQueueEnd] = ScanCode;
    KeyboardQueueEnd++;
    KeyboardQueueEnd %= KEYBOARD_BUFFER_SIZE;

    /* Since we inserted a value, it's not empty anymore */
    KeyboardQueueEmpty = FALSE;

    return TRUE;
}

static BOOLEAN KeyboardQueuePop(BYTE *ScanCode)
{
    /* Make sure the keyboard queue is not empty */
    if (KeyboardQueueEmpty) return FALSE;

    /* Get the scan code */
    *ScanCode = KeyboardQueue[KeyboardQueueStart];

    /* Remove the value from the queue */
    KeyboardQueueStart++;
    KeyboardQueueStart %= KEYBOARD_BUFFER_SIZE;

    /* Check if the queue is now empty */
    if (KeyboardQueueStart == KeyboardQueueEnd)
    {
        KeyboardQueueEmpty = TRUE;
    }

    return TRUE;
}

/* PUBLIC FUNCTIONS ***********************************************************/

BYTE KeyboardReadStatus()
{
    BYTE Status = 0;

    /* Set the first bit if the data can be read */
    if (KeyboardReadResponse || !KeyboardQueueEmpty) Status |= 1 << 0;

    /* Always set bit 2 */
    Status |= 1 << 2;

    /* Set bit 3 if the next byte goes to the controller */
    if (KeyboardWriteResponse) Status |= 1 << 3;

    return Status;
}

VOID KeyboardWriteCommand(BYTE Command)
{
    switch (Command)
    {
        /* Read configuration byte */
        case 0x20:
        {
            KeyboardResponse = KeyboardConfig;
            KeyboardReadResponse = TRUE;

            break;
        }

        /* Write configuration byte */
        case 0x60:
        /* Write controller output port */
        case 0xD1:
        /* Write keyboard output buffer */
        case 0xD2:
        /* Write mouse output buffer */
        case 0xD3:
        /* Write mouse input buffer */
        case 0xD4:
        {
            /* These commands require a response */
            KeyboardResponse = Command;
            KeyboardWriteResponse = TRUE;

            break;
        }

        /* Disable mouse */
        case 0xA7:
        {
            // TODO: Mouse support

            break;
        }

        /* Enable mouse */
        case 0xA8:
        {
            // TODO: Mouse support

            break;
        }

        /* Test mouse port */
        case 0xA9:
        {
            KeyboardResponse = 0;
            KeyboardReadResponse = TRUE;

            break;
        }

        /* Test PS/2 controller */
        case 0xAA:
        {
            KeyboardResponse = 0x55;
            KeyboardReadResponse = TRUE;

            break;
        }

        /* Disable keyboard */
        case 0xAD:
        {
            // TODO: Not implemented
            break;
        }

        /* Enable keyboard */
        case 0xAE:
        {
            // TODO: Not implemented
            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 simulation */
            VdmRunning = FALSE;

            break;
        }
    }
}

BYTE KeyboardReadData()
{
    BYTE Value = 0;

    /* If there was a response byte from the controller, return it */
    if (KeyboardReadResponse)
    {
        KeyboardReadResponse = FALSE;
        return KeyboardResponse;
    }
    
    /* Otherwise, read the data from the queue */
    KeyboardQueuePop(&Value);

    return Value;
}

VOID KeyboardWriteData(BYTE Data)
{
    /* Check if the controller is waiting for a response */
    if (KeyboardWriteResponse)
    {
        KeyboardWriteResponse = FALSE;

        /* Check which command it was */
        switch (KeyboardResponse)
        {
            /* Write configuration byte */
            case 0x60:
            {
                KeyboardConfig = Data;
                break;
            }

            /* Write controller output */
            case 0xD1:
            {
                /* Check if bit 0 is unset */
                if (!(Data & (1 << 0)))
                {
                    /* CPU disabled - end simulation */
                    VdmRunning = FALSE;
                }

                /* Update the A20 line setting */
                EmulatorSetA20(Data & (1 << 1));

                break;
            }
            
            case 0xD2:
            {
                /* Push the data byte to the keyboard queue */
                KeyboardQueuePush(Data);

                break;
            }

            case 0xD3:
            {
                // TODO: Mouse support
                break;
            }

            case 0xD4:
            {
                // TODO: Mouse support
                break;
            }
        }

        return;
    }

    // TODO: Implement PS/2 device commands
}

VOID CheckForInputEvents()
{
    PINPUT_RECORD Buffer;
    HANDLE ConsoleInput = GetStdHandle(STD_INPUT_HANDLE);
    DWORD i, j, Count, TotalEvents;
    BYTE ScanCode;

    /* Get the number of input events */
    if (!GetNumberOfConsoleInputEvents(ConsoleInput, &Count)) return;
    if (Count == 0) return;

    /* Allocate the buffer */
    Buffer = (PINPUT_RECORD)HeapAlloc(GetProcessHeap(), 0, Count * sizeof(INPUT_RECORD));
    if (Buffer == NULL) return;

    /* Peek the input events */
    if (!ReadConsoleInput(ConsoleInput, Buffer, Count, &TotalEvents)) goto Cleanup;

    for (i = 0; i < TotalEvents; i++)
    {
        /* Check if this is a key event */
        if (Buffer[i].EventType != KEY_EVENT) continue;

        /* Get the scan code */
        ScanCode = Buffer[i].Event.KeyEvent.wVirtualScanCode;

        /* If this is a key release, set the highest bit in the scan code */
        if (!Buffer[i].Event.KeyEvent.bKeyDown) ScanCode |= 0x80;

        /* Push the scan code onto the keyboard queue */
        for (j = 0; j < Buffer[i].Event.KeyEvent.wRepeatCount; j++)
        {
            KeyboardQueuePush(ScanCode);
        }

        /* Yes, IRQ 1 */
        PicInterruptRequest(1);

        /* Stop the loop */
        break;
    }

Cleanup:
    HeapFree(GetProcessHeap(), 0, Buffer);
}

/* EOF */