void tty_setcursor(int x, int y) {
int offset = tty_getoffset(x, y);
port_byte_out(REG_SCREEN_CTRL, 14);
port_byte_out(REG_SCREEN_DATA, (uint8_t)(offset >> 8));
port_byte_out(REG_SCREEN_CTRL, 15);
port_byte_out(REG_SCREEN_DATA, (uint8_t)(offset & 0xFF));
}
int tty_getcursor() {
port_byte_out(REG_SCREEN_CTRL, 14);
int offset = port_byte_in(REG_SCREEN_DATA) << 8;
port_byte_out(REG_SCREEN_CTRL, 15);
offset += port_byte_in(REG_SCREEN_DATA);
return offset;
}
void set_cursor_offset(int offset) {
/* Similar to get_cursor_offset, but instead of reading we write data */
offset /= 2;
port_byte_out(REG_SCREEN_CTRL, 14);
port_byte_out(REG_SCREEN_DATA, (unsigned char)(offset >> 8));
port_byte_out(REG_SCREEN_CTRL, 15);
port_byte_out(REG_SCREEN_DATA, (unsigned char)(offset & 0xff));
}
static void set_cursor(struct cursor cur)
{
uint16_t offset = get_offset(cur);
port_byte_out(CTRL_PORT, 14);
port_byte_out(DATA_PORT, (uint8_t)(offset >> 8));
port_byte_out(CTRL_PORT, 15);
port_byte_out(DATA_PORT, (uint8_t)(offset));
}
int get_cursor_offset() {
/* Use the VGA ports to get the current cursor position
* 1. Ask for high byte of the cursor offset (data 14)
* 2. Ask for low byte (data 15)
*/
port_byte_out(REG_SCREEN_CTRL, 14);
int offset = port_byte_in(REG_SCREEN_DATA) << 8; /* High byte: << 8 */
port_byte_out(REG_SCREEN_CTRL, 15);
offset += port_byte_in(REG_SCREEN_DATA);
return offset * 2; /* Position * size of character cell */
}
void set_cursor(int nOffset)
{
nOffset /= 2;
// This is similar to get cursor, only now we write
// bytes to those interal device registers
port_byte_out(REG_SCREEN_CTRL, 14);
port_byte_out(REG_SCREEN_DATA, (unsigned char)((nOffset >> 8) & 0xff));
port_byte_out(REG_SCREEN_CTRL, 15);
port_byte_out(REG_SCREEN_DATA, (unsigned char)(nOffset & 0xff));
}
void irq_handler(registers_t *r) {
/* After every interrupt we need to send an EOI to the PICs
* or they will not send another interrupt again */
if (r->int_no >= 40) port_byte_out(0xA0, 0x20); /* slave */
port_byte_out(0x20, 0x20); /* master */
/* Handle the interrupt in a more modular way */
if (interrupt_handlers[r->int_no] != 0) {
isr_t handler = interrupt_handlers[r->int_no];
handler(r);
}
}
static struct cursor get_cursor(void)
{
port_byte_out(CTRL_PORT, 14);
uint8_t high_byte = port_byte_in(DATA_PORT);
port_byte_out(CTRL_PORT, 15);
uint8_t low_byte = port_byte_in(DATA_PORT);
uint16_t offset = high_byte;
offset <<= 8;
offset += low_byte;
struct cursor cur = {(uint16_t)(offset / MAX_COLS),
(uint16_t)(offset % MAX_COLS)};
return cur;
}
void init_timer(u32 freq) {
/* Install the function we just wrote */
register_interrupt_handler(IRQ0, timer_callback);
/* Get the PIT value: hardware clock at 1193180 Hz */
u32 divisor = 1193180 / freq;
u8 low = (u8)(divisor & 0xFF);
u8 high = (u8)( (divisor >> 8) & 0xFF);
/* Send the command */
port_byte_out(0x43, 0x36); /* Command port */
port_byte_out(0x40, low);
port_byte_out(0x40, high);
}
void irq_handler(registers_t regs) {
void (*handler)(struct registers *r) = irq_handlers[regs.int_no];
if(handler != 0) {
handler(®s);
}
//Did this come from the slave PIC?
if (regs.int_no >= 8) {
port_byte_out(SLAVE_COMMAND, PIC_EOI);
}
port_byte_out(MASTER_COMMAND, PIC_EOI);
}
void init_interrupts(void)
{
init_idt();
port_byte_out(0x20, 0x11);
port_byte_out(0xA0, 0x11);
port_byte_out(0x21, 0x20);
port_byte_out(0xA1, 0x28);
port_byte_out(0x21, 0x04);
port_byte_out(0xA1, 0x02);
port_byte_out(0x21, 0x01);
port_byte_out(0xA1, 0x01);
port_byte_out(0x21, 0x0);
port_byte_out(0xA1, 0x0);
__asm__ __volatile__("lidt (%0)"::"r" (&idt_register));
__asm__ __volatile__("sti");
}
int get_cursor()
{
// The device uses its control register as an index
// to select its interl registers, in which we are
// interested in
// reg 14: which is the high byte of cursor offset
// reg 15: which is the low byte of cursor offet
port_byte_out(REG_SCREEN_CTRL, 14);
int nOffset = port_byte_in(REG_SCREEN_DATA) << 8;
port_byte_out(REG_SCREEN_CTRL, 15);
nOffset += port_byte_in(REG_SCREEN_DATA);
// Since the cursor offset reported by the VGA hardware
// is the number of characters, we have to multiply it
// by two to convert it to a character cell offset
return nOffset * 2;
}
void remap_pic() {
//Send ICW1 to the CMD ports
port_byte_out(MASTER_COMMAND, PIC_ICW1);
port_byte_out(SLAVE_COMMAND, PIC_ICW1);
//Send ICW2 to the DATA ports
port_byte_out(MASTER_DATA, 0x20); //IRQ0 = IDT #32
port_byte_out(SLAVE_DATA, 0x28); //IRQ8 = IDT #40
//Send ICW3 to the DATA ports
port_byte_out(MASTER_DATA, PIC_ICW3m);
port_byte_out(SLAVE_DATA, PIC_ICW3s);
//Send ICW4 to the DATA ports
port_byte_out(MASTER_DATA, PIC_ICW4m);
port_byte_out(SLAVE_DATA, PIC_ICW4s);
//Unmask ALL the IRQs!
port_byte_out(MASTER_DATA, 0);
port_byte_out(SLAVE_DATA, 0);
}
/* Can't do this with a loop because we need the address
* of the function names */
void isr_install() {
set_idt_gate(0, (uint32_t)isr0);
set_idt_gate(1, (uint32_t)isr1);
set_idt_gate(2, (uint32_t)isr2);
set_idt_gate(3, (uint32_t)isr3);
set_idt_gate(4, (uint32_t)isr4);
set_idt_gate(5, (uint32_t)isr5);
set_idt_gate(6, (uint32_t)isr6);
set_idt_gate(7, (uint32_t)isr7);
set_idt_gate(8, (uint32_t)isr8);
set_idt_gate(9, (uint32_t)isr9);
set_idt_gate(10, (uint32_t)isr10);
set_idt_gate(11, (uint32_t)isr11);
set_idt_gate(12, (uint32_t)isr12);
set_idt_gate(13, (uint32_t)isr13);
set_idt_gate(14, (uint32_t)isr14);
set_idt_gate(15, (uint32_t)isr15);
set_idt_gate(16, (uint32_t)isr16);
set_idt_gate(17, (uint32_t)isr17);
set_idt_gate(18, (uint32_t)isr18);
set_idt_gate(19, (uint32_t)isr19);
set_idt_gate(20, (uint32_t)isr20);
set_idt_gate(21, (uint32_t)isr21);
set_idt_gate(22, (uint32_t)isr22);
set_idt_gate(23, (uint32_t)isr23);
set_idt_gate(24, (uint32_t)isr24);
set_idt_gate(25, (uint32_t)isr25);
set_idt_gate(26, (uint32_t)isr26);
set_idt_gate(27, (uint32_t)isr27);
set_idt_gate(28, (uint32_t)isr28);
set_idt_gate(29, (uint32_t)isr29);
set_idt_gate(30, (uint32_t)isr30);
set_idt_gate(31, (uint32_t)isr31);
// Remap the PIC
port_byte_out(0x20, 0x11);
port_byte_out(0xA0, 0x11);
port_byte_out(0x21, 0x20);
port_byte_out(0xA1, 0x28);
port_byte_out(0x21, 0x04);
port_byte_out(0xA1, 0x02);
port_byte_out(0x21, 0x01);
port_byte_out(0xA1, 0x01);
port_byte_out(0x21, 0x0);
port_byte_out(0xA1, 0x0);
// Install the IRQs
set_idt_gate(32, (uint32_t)irq0);
set_idt_gate(33, (uint32_t)irq1);
set_idt_gate(34, (uint32_t)irq2);
set_idt_gate(35, (uint32_t)irq3);
set_idt_gate(36, (uint32_t)irq4);
set_idt_gate(37, (uint32_t)irq5);
set_idt_gate(38, (uint32_t)irq6);
set_idt_gate(39, (uint32_t)irq7);
set_idt_gate(40, (uint32_t)irq8);
set_idt_gate(41, (uint32_t)irq9);
set_idt_gate(42, (uint32_t)irq10);
set_idt_gate(43, (uint32_t)irq11);
set_idt_gate(44, (uint32_t)irq12);
set_idt_gate(45, (uint32_t)irq13);
set_idt_gate(46, (uint32_t)irq14);
set_idt_gate(47, (uint32_t)irq15);
set_idt(); // Load with ASM
}
