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#include<stdbool.h>
#include<stddef.h>
#include<stdint.h>
#include"keyboard.h"
#define BUFFER_SIZE 200
char buffer[BUFFER_SIZE];
size_t buffer_index=0;
#define PIC1_COMMAND_PORT 0x20
#define PIC1_DATA_PORT 0x21
#define PIC2_COMMAND_PORT 0xA0
#define PIC2_DATA_PORT 0xA1
// IO Ports for Keyboard
#define KEYBOARD_DATA_PORT 0x60
#define KEYBOARD_STATUS_PORT 0x64
extern char ioport_in(uint8_t port);
extern void ioport_out(uint8_t port, char data);
void previous_field();
void terminal_putchar(char c);
void tty(char *buffer);
void prompt();
void init_keyboard()
{
// 0xFD = 1111 1101 in binary. enables only IRQ1
// Why IRQ1? Remember, IRQ0 exists, it's 0-based
ioport_out(PIC1_DATA_PORT, 0xFD);
}
void backspace()
{
if(buffer_index<=0) return;
previous_field();
terminal_putchar(' ');
previous_field();
buffer[--buffer_index]='\0';
return;
}
void enter()
{
terminal_putchar('\n');
if(buffer_index>0)
{
tty(buffer);
for(int i=0;i<BUFFER_SIZE;i++) buffer[i]='\0';
buffer_index=0;
}
prompt();
return;
}
void handle_keyboard_interrupt()
{
// Write end of interrupt (EOI)
ioport_out(PIC1_COMMAND_PORT, 0x20);
unsigned char status = ioport_in(KEYBOARD_STATUS_PORT);
// Lowest bit of status will be set if buffer not empty
if (status & 0x1)
{
int16_t keycode = ioport_in(KEYBOARD_DATA_PORT);
if (keycode < 0 || keycode >= 128) return;
if(keycode==14) backspace();
else if(keycode==28) enter();
else
{
buffer[buffer_index++]=keyboard[keycode];
terminal_putchar(keyboard[keycode]);
}
}
}
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