In my attempts to make a keyboard driver (modified from brans kern dev, wanted to add a buffer system), I've come up with this.
If I pull the while out of my getch() and do it in the interrupt itself, I can get the characters to print out.
However, set up this way, the while seems to block the keyboard? in my main.c I do
keyboard_buffer_clear();
getch();
puts("hello world"); <- never gets here.
Unsure what I am doing wrong at this point. Need a bump. Thanks!
Code: Select all
/*
* slightly modified bkerndev driver
* Desc: Keyboard driver
*
* */
#include <system.h>
unsigned char *kbdbuf[255]; // keyboard buffer
int bufcount = 0; // position in buffer
int i; // iterator var
int shift = 0;
int capslock = 0;
int control = 0;
/* KBDUS means US Keyboard Layout. This is a scancode table
* used to layout a standard US keyboard. I have left some
* comments in to give you an idea of what key is what, even
* though I set it's array index to 0. You can change that to
* whatever you want using a macro, if you wish! */
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 */
0, /* 29 - Control */
'a', 's', 'd', 'f', 'g', 'h', 'j', 'k', 'l', ';', /* 39 */
'\'', '`', 0, /* Left shift */
'\\', 'z', 'x', 'c', 'v', 'b', 'n', /* 49 */
'm', ',', '.', '/', 0, /* Right shift */
'*',
0, /* 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 kbdcapsus[128] =
{
0, 27, '!', '@', '#', '$', '%', '^', '&', '*', /* 9 */
'(', ')', '_', '+', '\b', /* Backspace */
'\t', /* Tab */
'Q', 'W', 'E', 'R', /* 19 */
'T', 'Y', 'U', 'I', 'O', 'P', '{', '}', '\n', /* Enter key */
0, /* 29 - Control */
'A', 'S', 'D', 'F', 'G', 'H', 'J', 'K', 'L', ':', /* 39 */
'\"', '~', 0, /* Left shift */
'|', 'Z', 'X', 'C', 'V', 'B', 'N', /* 49 */
'M', '<', '>', '?', 0, /* Right shift */
'*',
0, /* 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 */
};
// TODO: Third keyboard handler for capslock behavior?
/* Handles the keyboard interrupt */
void keyboard_handler(struct regs *r)
{
unsigned char scancode;
/* Read from the keyboard's data buffer */
scancode = inportb(0x60);
/* If the top bit of the byte we read from the keyboard is
* set, that means that a key has just been released */
if (scancode & 0x80)
{
/* You can use this one to see if the user released the
* shift, alt, or control keys... */
switch(scancode)
{
case 0xAA:
// 0xAA == 0x2A | 0x80 - the left shift key break code
shift = 0;
break;
case 0xB6:
// right shift key break code
shift = 0;
break;
}
}
else
{
// KEYPRESS: SHIFT
if(scancode == 0x2A || scancode == 0x36)
{
shift = 1;
}
bufcount += 1;
kbdbuf[bufcount - 1] = kbdus[scancode];
if(shift == 1) {
kbdbuf[bufcount - 1] = kbdcapsus[scancode];
}
if(bufcount == 255) {
keyboard_clear_buffer();
}
}
}
void keyboard_clear_buffer()
{
for(i=0;i<=255;i++)
{
kbdbuf[i - 1] = '00';
}
bufcount = 0;
}
unsigned char getch()
{
unsigned char retval = 0;
while(bufcount == 0);
retval = kbdbuf[bufcount - 1];
kbdbuf[bufcount - 1] = '00';
bufcount -= 1;
return retval;
}
/* Installs the keyboard handler into IRQ1 */
void keyboard_install()
{
irq_install_handler(1, keyboard_handler);
}
