console.c
#include <defs.h>
#include <x86.h>
#include <stdio.h>
#include <string.h>
#include <kbdreg.h>
#include <picirq.h>
#include <trap.h>
#include <memlayout.h>
#include <sync.h>
/* stupid I/O delay routine necessitated by historical PC design flaws */
static void
delay(void) {
inb(0x84);
inb(0x84);
inb(0x84);
inb(0x84);
}
/***** Serial I/O code *****/
#define COM1 0x3F8
#define COM_RX 0 // In: Receive buffer (DLAB=0)
#define COM_TX 0 // Out: Transmit buffer (DLAB=0)
#define COM_DLL 0 // Out: Divisor Latch Low (DLAB=1)
#define COM_DLM 1 // Out: Divisor Latch High (DLAB=1)
#define COM_IER 1 // Out: Interrupt Enable Register
#define COM_IER_RDI 0x01 // Enable receiver data interrupt
#define COM_IIR 2 // In: Interrupt ID Register
#define COM_FCR 2 // Out: FIFO Control Register
#define COM_LCR 3 // Out: Line Control Register
#define COM_LCR_DLAB 0x80 // Divisor latch access bit
#define COM_LCR_WLEN8 0x03 // Wordlength: 8 bits
#define COM_MCR 4 // Out: Modem Control Register
#define COM_MCR_RTS 0x02 // RTS complement
#define COM_MCR_DTR 0x01 // DTR complement
#define COM_MCR_OUT2 0x08 // Out2 complement
#define COM_LSR 5 // In: Line Status Register
#define COM_LSR_DATA 0x01 // Data available
#define COM_LSR_TXRDY 0x20 // Transmit buffer avail
#define COM_LSR_TSRE 0x40 // Transmitter off
#define MONO_BASE 0x3B4
#define MONO_BUF 0xB0000
#define CGA_BASE 0x3D4
#define CGA_BUF 0xB8000
#define CRT_ROWS 25
#define CRT_COLS 80
#define CRT_SIZE (CRT_ROWS * CRT_COLS)
#define LPTPORT 0x378
static uint16_t *crt_buf;
static uint16_t crt_pos;
static uint16_t addr_6845;
/* TEXT-mode CGA/VGA display output */
static void
cga_init(void) {
volatile uint16_t *cp = (uint16_t *)(CGA_BUF + KERNBASE);
uint16_t was = *cp;
*cp = (uint16_t) 0xA55A;
if (*cp != 0xA55A) {
cp = (uint16_t*)(MONO_BUF + KERNBASE);
addr_6845 = MONO_BASE;
} else {
*cp = was;
addr_6845 = CGA_BASE;
}
// Extract cursor location
uint32_t pos;
outb(addr_6845, 14);
pos = inb(addr_6845 + 1) << 8;
outb(addr_6845, 15);
pos |= inb(addr_6845 + 1);
crt_buf = (uint16_t*) cp;
crt_pos = pos;
}
static bool serial_exists = 0;
static void
serial_init(void) {
// Turn off the FIFO
outb(COM1 + COM_FCR, 0);
// Set speed; requires DLAB latch
outb(COM1 + COM_LCR, COM_LCR_DLAB);
outb(COM1 + COM_DLL, (uint8_t) (115200 / 9600));
outb(COM1 + COM_DLM, 0);
// 8 data bits, 1 stop bit, parity off; turn off DLAB latch
outb(COM1 + COM_LCR, COM_LCR_WLEN8 & ~COM_LCR_DLAB);
// No modem controls
outb(COM1 + COM_MCR, 0);
// Enable rcv interrupts
outb(COM1 + COM_IER, COM_IER_RDI);
// Clear any preexisting overrun indications and interrupts
// Serial port doesn't exist if COM_LSR returns 0xFF
serial_exists = (inb(COM1 + COM_LSR) != 0xFF);
(void) inb(COM1+COM_IIR);
(void) inb(COM1+COM_RX);
if (serial_exists) {
pic_enable(IRQ_COM1);
}
}
static void
lpt_putc_sub(int c) {
int i;
for (i = 0; !(inb(LPTPORT + 1) & 0x80) && i < 12800; i ++) {
delay();
}
outb(LPTPORT + 0, c);
outb(LPTPORT + 2, 0x08 | 0x04 | 0x01);
outb(LPTPORT + 2, 0x08);
}
/* lpt_putc - copy console output to parallel port */
static void
lpt_putc(int c) {
if (c != '\b') {
lpt_putc_sub(c);
}
else {
lpt_putc_sub('\b');
lpt_putc_sub(' ');
lpt_putc_sub('\b');
}
}
/* cga_putc - print character to console */
static void
cga_putc(int c) {
// set black on white
if (!(c & ~0xFF)) {
c |= 0x0700;
}
switch (c & 0xff) {
case '\b':
if (crt_pos > 0) {
crt_pos --;
crt_buf[crt_pos] = (c & ~0xff) | ' ';
}
break;
case '\n':
crt_pos += CRT_COLS;
case '\r':
crt_pos -= (crt_pos % CRT_COLS);
break;
default:
crt_buf[crt_pos ++] = c; // write the character
break;
}
// What is the purpose of this?
if (crt_pos >= CRT_SIZE) {
int i;
memmove(crt_buf, crt_buf + CRT_COLS, (CRT_SIZE - CRT_COLS) * sizeof(uint16_t));
for (i = CRT_SIZE - CRT_COLS; i < CRT_SIZE; i ++) {
crt_buf[i] = 0x0700 | ' ';
}
crt_pos -= CRT_COLS;
}
// move that little blinky thing
outb(addr_6845, 14);
outb(addr_6845 + 1, crt_pos >> 8);
outb(addr_6845, 15);
outb(addr_6845 + 1, crt_pos);
}
static void
serial_putc_sub(int c) {
int i;
for (i = 0; !(inb(COM1 + COM_LSR) & COM_LSR_TXRDY) && i < 12800; i ++) {
delay();
}
outb(COM1 + COM_TX, c);
}
/* serial_putc - print character to serial port */
static void
serial_putc(int c) {
if (c != '\b') {
serial_putc_sub(c);
}
else {
serial_putc_sub('\b');
serial_putc_sub(' ');
serial_putc_sub('\b');
}
}
/* *
* Here we manage the console input buffer, where we stash characters
* received from the keyboard or serial port whenever the corresponding
* interrupt occurs.
* */
#define CONSBUFSIZE 512
static struct {
uint8_t buf[CONSBUFSIZE];
uint32_t rpos;
uint32_t wpos;
} cons;
/* *
* cons_intr - called by device interrupt routines to feed input
* characters into the circular console input buffer.
* */
static void
cons_intr(int (*proc)(void)) {
int c;
while ((c = (*proc)()) != -1) {
if (c != 0) {
cons.buf[cons.wpos ++] = c;
if (cons.wpos == CONSBUFSIZE) {
cons.wpos = 0;
}
}
}
}
/* serial_proc_data - get data from serial port */
static int
serial_proc_data(void) {
if (!(inb(COM1 + COM_LSR) & COM_LSR_DATA)) {
return -1;
}
int c = inb(COM1 + COM_RX);
if (c == 127) {
c = '\b';
}
return c;
}
/* serial_intr - try to feed input characters from serial port */
void
serial_intr(void) {
if (serial_exists) {
cons_intr(serial_proc_data);
}
}
/***** Keyboard input code *****/
#define NO 0
#define SHIFT (1<<0)
#define CTL (1<<1)
#define ALT (1<<2)
#define CAPSLOCK (1<<3)
#define NUMLOCK (1<<4)
#define SCROLLLOCK (1<<5)
#define E0ESC (1<<6)
static uint8_t shiftcode[256] = {
[0x1D] CTL,
[0x2A] SHIFT,
[0x36] SHIFT,
[0x38] ALT,
[0x9D] CTL,
[0xB8] ALT
};
static uint8_t togglecode[256] = {
[0x3A] CAPSLOCK,
[0x45] NUMLOCK,
[0x46] SCROLLLOCK
};
static uint8_t normalmap[256] = {
NO, 0x1B, '1', '2', '3', '4', '5', '6', // 0x00
'7', '8', '9', '0', '-', '=', '\b', '\t',
'q', 'w', 'e', 'r', 't', 'y', 'u', 'i', // 0x10
'o', 'p', '[', ']', '\n', NO, 'a', 's',
'd', 'f', 'g', 'h', 'j', 'k', 'l', ';', // 0x20
'\'', '`', NO, '\\', 'z', 'x', 'c', 'v',
'b', 'n', 'm', ',', '.', '/', NO, '*', // 0x30
NO, ' ', NO, NO, NO, NO, NO, NO,
NO, NO, NO, NO, NO, NO, NO, '7', // 0x40
'8', '9', '-', '4', '5', '6', '+', '1',
'2', '3', '0', '.', NO, NO, NO, NO, // 0x50
[0xC7] KEY_HOME, [0x9C] '\n' /*KP_Enter*/,
[0xB5] '/' /*KP_Div*/, [0xC8] KEY_UP,
[0xC9] KEY_PGUP, [0xCB] KEY_LF,
[0xCD] KEY_RT, [0xCF] KEY_END,
[0xD0] KEY_DN, [0xD1] KEY_PGDN,
[0xD2] KEY_INS, [0xD3] KEY_DEL
};
static uint8_t shiftmap[256] = {
NO, 033, '!', '@', '#', '$', '%', '^', // 0x00
'&', '*', '(', ')', '_', '+', '\b', '\t',
'Q', 'W', 'E', 'R', 'T', 'Y', 'U', 'I', // 0x10
'O', 'P', '{', '}', '\n', NO, 'A', 'S',
'D', 'F', 'G', 'H', 'J', 'K', 'L', ':', // 0x20
'"', '~', NO, '|', 'Z', 'X', 'C', 'V',
'B', 'N', 'M', '<', '>', '?', NO, '*', // 0x30
NO, ' ', NO, NO, NO, NO, NO, NO,
NO, NO, NO, NO, NO, NO, NO, '7', // 0x40
'8', '9', '-', '4', '5', '6', '+', '1',
'2', '3', '0', '.', NO, NO, NO, NO, // 0x50
[0xC7] KEY_HOME, [0x9C] '\n' /*KP_Enter*/,
[0xB5] '/' /*KP_Div*/, [0xC8] KEY_UP,
[0xC9] KEY_PGUP, [0xCB] KEY_LF,
[0xCD] KEY_RT, [0xCF] KEY_END,
[0xD0] KEY_DN, [0xD1] KEY_PGDN,
[0xD2] KEY_INS, [0xD3] KEY_DEL
};
#define C(x) (x - '@')
static uint8_t ctlmap[256] = {
NO, NO, NO, NO, NO, NO, NO, NO,
NO, NO, NO, NO, NO, NO, NO, NO,
C('Q'), C('W'), C('E'), C('R'), C('T'), C('Y'), C('U'), C('I'),
C('O'), C('P'), NO, NO, '\r', NO, C('A'), C('S'),
C('D'), C('F'), C('G'), C('H'), C('J'), C('K'), C('L'), NO,
NO, NO, NO, C('\\'), C('Z'), C('X'), C('C'), C('V'),
C('B'), C('N'), C('M'), NO, NO, C('/'), NO, NO,
[0x97] KEY_HOME,
[0xB5] C('/'), [0xC8] KEY_UP,
[0xC9] KEY_PGUP, [0xCB] KEY_LF,
[0xCD] KEY_RT, [0xCF] KEY_END,
[0xD0] KEY_DN, [0xD1] KEY_PGDN,
[0xD2] KEY_INS, [0xD3] KEY_DEL
};
static uint8_t *charcode[4] = {
normalmap,
shiftmap,
ctlmap,
ctlmap
};
/* *
* kbd_proc_data - get data from keyboard
*
* The kbd_proc_data() function gets data from the keyboard.
* If we finish a character, return it, else 0. And return -1 if no data.
* */
static int
kbd_proc_data(void) {
int c;
uint8_t data;
static uint32_t shift;
if ((inb(KBSTATP) & KBS_DIB) == 0) {
return -1;
}
data = inb(KBDATAP);
if (data == 0xE0) {
// E0 escape character
shift |= E0ESC;
return 0;
} else if (data & 0x80) {
// Key released
data = (shift & E0ESC ? data : data & 0x7F);
shift &= ~(shiftcode[data] | E0ESC);
return 0;
} else if (shift & E0ESC) {
// Last character was an E0 escape; or with 0x80
data |= 0x80;
shift &= ~E0ESC;
}
shift |= shiftcode[data];
shift ^= togglecode[data];
c = charcode[shift & (CTL | SHIFT)][data];
if (shift & CAPSLOCK) {
if ('a' <= c && c <= 'z')
c += 'A' - 'a';
else if ('A' <= c && c <= 'Z')
c += 'a' - 'A';
}
// Process special keys
// Ctrl-Alt-Del: reboot
if (!(~shift & (CTL | ALT)) && c == KEY_DEL) {
cprintf("Rebooting!\n");
outb(0x92, 0x3); // courtesy of Chris Frost
}
return c;
}
/* kbd_intr - try to feed input characters from keyboard */
static void
kbd_intr(void) {
cons_intr(kbd_proc_data);
}
static void
kbd_init(void) {
// drain the kbd buffer
kbd_intr();
pic_enable(IRQ_KBD);
}
/* cons_init - initializes the console devices */
void
cons_init(void) {
cga_init();
serial_init();
kbd_init();
if (!serial_exists) {
cprintf("serial port does not exist!!\n");
}
}
/* cons_putc - print a single character @c to console devices */
void
cons_putc(int c) {
bool intr_flag;
local_intr_save(intr_flag);
{
lpt_putc(c);
cga_putc(c);
serial_putc(c);
}
local_intr_restore(intr_flag);
}
/* *
* cons_getc - return the next input character from console,
* or 0 if none waiting.
* */
int
cons_getc(void) {
int c = 0;
bool intr_flag;
local_intr_save(intr_flag);
{
// poll for any pending input characters,
// so that this function works even when interrupts are disabled
// (e.g., when called from the kernel monitor).
serial_intr();
kbd_intr();
// grab the next character from the input buffer.
if (cons.rpos != cons.wpos) {
c = cons.buf[cons.rpos ++];
if (cons.rpos == CONSBUFSIZE) {
cons.rpos = 0;
}
}
}
local_intr_restore(intr_flag);
return c;
}Last updated