pepperOS/src/kbd/ps2.c

// PS/2 Keyboard support

#include "../io/serial.h"
#include "../io/printf.h"
#include "ps2.h"
#include <stdint.h>
#include "../io/term.h"

// The key status bitfield will be used to see if ALT, CONTROL, or SHIFT is pressed
uint8_t key_status = 0b00000000;

// Keymap pointers so we can change between different layouts
unsigned char* keymap;
unsigned char* keymap_shifted;

unsigned char kbdus[128] =
{
    0,  27, '1', '2', '3', '4', '5', '6', '7', '8',	/* 9 */
    '9', '0', '-', '=', '\b',	/* Backspace */
    '\t', /* Tab */
    'q', 'w', 'e', 'r',	/* 19 */
    't', 'y', 'u', 'i', 'o', 'p', '[', ']', '\n',	/* Enter key */
    CTRL,			/* 29   - Control */
    'a', 's', 'd', 'f', 'g', 'h', 'j', 'k', 'l', ';',	/* 39 */
    '\'', '`',   SHIFT,		/* Left shift */
    '\\', 'z', 'x', 'c', 'v', 'b', 'n',			/* 49 */
    'm', ',', '.', '/',   SHIFT,				/* Right shift */
    '*',
    ALT,	/* Alt */
  ' ',	/* Space bar */
    0,	/* Caps lock */
    0,	/* 59 - F1 key ... > */
    0,   0,   0,   0,   0,   0,   0,   0,
    0,	/* < ... F10 */
    0,	/* 69 - Num lock*/
    0,	/* Scroll Lock */
    0,	/* Home key */
    0,	/* Up Arrow */
    0,	/* Page Up */
    '-',
    0,	/* Left Arrow */
    0,
    0,	/* Right Arrow */
    '+',
    0,	/* 79 - End key*/
    0,	/* Down Arrow */
    0,	/* Page Down */
    0,	/* Insert Key */
    0,	/* Delete Key */
    0,   0,   0,
    0,	/* F11 Key */
    0,	/* F12 Key */
    0,	/* All other keys are undefined */
};

unsigned char kbdus_shifted[128] =
{
    0,  27, '!', '@', '#', '$', '%', '^', '&', '*',   /* 9 */
    '(', ')', '_', '+', '\b',                        /* Backspace */
    '\t',                                            /* Tab */
    'Q', 'W', 'E', 'R',                               /* 19 */
    'T', 'Y', 'U', 'I', 'O', 'P', '{', '}', '\n',     /* Enter */
    CTRL,                                            /* 29 */
    'A', 'S', 'D', 'F', 'G', 'H', 'J', 'K', 'L', ':', /* 39 */
    '"', '~', SHIFT,                                 /* Left shift */
    '|', 'Z', 'X', 'C', 'V', 'B', 'N',                /* 49 */
    'M', '<', '>', '?', SHIFT,                        /* Right shift */
    '*',
    ALT,                                             /* Alt */
    ' ',                                             /* Space */
    0,                                               /* Caps lock */
    0, 0, 0, 0, 0, 0, 0, 0,
    0,                                               /* F10 */
    0,                                               /* Num lock */
    0,                                               /* Scroll lock */
    0, 0, 0,
    '-',
    0, 0, 0,
    '+',
    0, 0, 0,
    0, 0,
    0, 0, 0,
    0,                                               /* F11 */
    0                                                /* F12 */
};

// NOT THE REAL FR KEYMAP!!
// Some French keys have accents or weird symbols that aren't part of ASCII
// so they won't fit in 1 char. As a substitute for now, these will be
// changed to their ASCII counterparts (without accents, etc.)
unsigned char kbdfr[128] =
{
    0,  27, '&', 'e', '"', '\'', '(', '-', 'e', '_',
    'c', 'a', ')', '=', '\b',
    '\t',
    'a', 'z', 'e', 'r',
    't', 'y', 'u', 'i', 'o', 'p', '^', '$', '\n',
    CTRL,
    'q', 's', 'd', 'f', 'g', 'h', 'j', 'k', 'l', 'm',
    'u', '`', SHIFT,
    '*', 'w', 'x', 'c', 'v', 'b', 'n',
    ',', ';', ':', '!', SHIFT,
    '*',
    ALT,
    ' ',
    0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0,
    0,
    0,
    0, 0, 0,
    '-',
    0, 0, 0,
    '+',
    0, 0, 0,
    0, 0,
    0, 0, 0,
    0,
    0
};

unsigned char kbdfr_shifted[128] =
{
    0,  27, '1', '2', '3', '4', '5', '6', '7', '8',
    '9', '0', '^', '+', '\b',
    '\t',
    'A', 'Z', 'E', 'R',
    'T', 'Y', 'U', 'I', 'O', 'P', '^', 'L', '\n',
    CTRL,
    'Q', 'S', 'D', 'F', 'G', 'H', 'J', 'K', 'L', 'M',
    '%', '~', SHIFT,
    'u', 'W', 'X', 'C', 'V', 'B', 'N',
    '?', '.', '/', 'S', SHIFT,
    '*',
    ALT,
    ' ',
    0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0,
    0,
    0,
    0, 0, 0,
    '-',
    0, 0, 0,
    '+',
    0, 0, 0,
    0, 0,
    0, 0, 0,
    0,
    0
};

void keyboard_handler()
{
    unsigned char scancode = inb(0x60);

    // Key release (bit 7 set)
    if (scancode & 0x80)
    {
        unsigned char code = scancode & 0x7F;
        switch (code)
        {
            // Clear the corresponding bit if corresponding key is released
            case LEFT_SHIFT_PRESSED:
            case RIGHT_SHIFT_PRESSED:
                key_status &= ~SHIFT_PRESSED_BIT;
                break;
            case CTRL_PRESSED:
                key_status &= ~CTRL_PRESSED_BIT;
                break;
            case ALT_PRESSED:
                key_status &= ~ALT_PRESSED_BIT;
                break;
        }

        // Send EOI
        outb(0x20, 0x20);
        return;
    }
    else
    {
        // Key press
        switch (scancode)
        {
            // Set bits for corresponding special key press
            case LEFT_SHIFT_PRESSED:
            case RIGHT_SHIFT_PRESSED:
                key_status |= SHIFT_PRESSED_BIT;
                break;
            case CTRL_PRESSED:
                key_status |= CTRL_PRESSED_BIT;
                break;
            case ALT_PRESSED:
                key_status |= ALT_PRESSED_BIT;
                break;

            default:
            {
                // Should we get a SHIFTED char or a regular one?
                unsigned char c = (key_status & SHIFT_PRESSED_BIT) ? keymap_shifted[scancode] : keymap[scancode];

                if (c)
                {
                    putchar(c);
                }
            }
        }

        serial_kputs("key pressed!\n");
    }

    // End of Interrupt (to master PIC)
    outb(0x20, 0x20);
}

void keyboard_init(unsigned char layout)
{
    // Here we might go and select PS/2, USB, or other... (once we implement multiple keyboard protocols)

    // Keyboard layout selection
    switch (layout)
    {
        case US:
            keymap = kbdus;
            keymap_shifted = kbdus_shifted;
            break;
        case FR:
            keymap = kbdfr;
            keymap_shifted = kbdfr_shifted;
            break;
        
        default:
            serial_kputs("Unsupported layout.");
            break;
    }
}