/* See COPYRIGHT for copyright information. */
#include <inc/x86.h>
#include <inc/memlayout.h>
#include <inc/kbdreg.h>
#include <inc/string.h>
#include <inc/assert.h>
#include <kern/console.h>
static void cons_intr(int (*proc)(void));
static void cons_putc(int c);
// 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
static bool serial_exists;
static int
serial_proc_data(void)
{
if (!(inb(COM1+COM_LSR) & COM_LSR_DATA))
return -1;
return inb(COM1+COM_RX);
}
void
serial_intr(void)
{
if (serial_exists)
cons_intr(serial_proc_data);
}
static void
serial_putc(int c)
{
int i;
for (i = 0;
!(inb(COM1 + COM_LSR) & COM_LSR_TXRDY) && i < 12800;
i++)
delay();
outb(COM1 + COM_TX, c);
}
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);
}
/***** Parallel port output code *****/
// For information on PC parallel port programming, see the class References
// page.
static void
lpt_putc(int c)
{
int i;
for (i = 0; !(inb(0x378+1) & 0x80) && i < 12800; i++)
delay();
outb(0x378+0, c);
outb(0x378+2, 0x08|0x04|0x01);
outb(0x378+2, 0x08);
}
/***** Text-mode CGA/VGA display output *****/
static unsigned addr_6845;
static uint16_t *crt_buf;
static uint16_t crt_pos;
static void
cga_init(void)
{
volatile uint16_t *cp;
uint16_t was;
unsigned pos;
cp = (uint16_t*) (KERNBASE + CGA_BUF);
was = *cp;
*cp = (uint16_t) 0xA55A;
if (*cp != 0xA55A) {
cp = (uint16_t*) (KERNBASE + MONO_BUF);
addr_6845 = MONO_BASE;
} else {
*cp = was;
addr_6845 = CGA_BASE;
}
/* Extract cursor location */
/* 提取光标位置 */
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 void
cga_putc(int c)
{
//c为int类型占四个字节
// if no attribute given, then use black on white
// 0xFF二进制11111111 两个数做与操作，将0xFF补充到32位 所以0xFF = 00...000011111111(共32位）
// ~是按位取反运算符 所以~0xFF = 11...111100000000(共32位）
//c与11...111100000000作&运算目的是高8位保存，低24位变成0
if (!(c & ~0xFF)) //如果c高8位为0
c |= 0x0700; //则将c的高8位置为0x0700，根据英文注释可知，c的高8位控制了字符颜色
switch (c & 0xff) { //取c的低8位 根据选项内容可知c的低8位控制转义符
case '\b': //后退一格（Backspace）
if (crt_pos > 0) {
crt_pos--;
crt_buf[crt_pos] = (c & ~0xff) | ' ';
}
break;
case '\n': //换行
crt_pos += CRT_COLS;
/* fallthru */
case '\r': // 回车 光标回到本行的开头，如果继续输入的话会把先前的覆盖掉
crt_pos -= (crt_pos % CRT_COLS);
break;
case '\t': //tab键
cons_putc(' ');
cons_putc(' ');
cons_putc(' ');
cons_putc(' ');
cons_putc(' ');
break;
default:
crt_buf[crt_pos++] = c; /* write the character */
break;
}
// What is the purpose of this?
//crt_pos类型是16位无符号整型 根据case '反斜杠b' 推断 crt_pos 是光标位置
//猜测：如果输出语句后要显示的内容超出屏幕范围，则将滚动屏幕并将光标放在最后
//怎么猜的：已知这整段代码都在处理输出字符的颜色和转义符，所以这最后
//一段代码应该做的是“善后”工作，结合最后四个outb移动光标，做出此推测
if (crt_pos >= CRT_SIZE) {
int i;
//memmove用于拷贝字节
//将crt_buf + CRT_COLS所指内存区域复制(CRT_SIZE - CRT_COLS) * sizeof(uint16_t)个字节
//到crt_buf所指内存区域。
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 */
/* 把那个眨眼的小东西挪开 */
outb(addr_6845, 14);
outb(addr_6845 + 1, crt_pos >> 8);
outb(addr_6845, 15);
outb(addr_6845 + 1, crt_pos);
}
/***** 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
};
/*
* Get data from the keyboard. If we finish a character, return it. Else 0.
* Return -1 if no data.
*/
static int
kbd_proc_data(void)
{
int c;
uint8_t stat, data;
static uint32_t shift;
stat = inb(KBSTATP);
if ((stat & KBS_DIB) == 0)
return -1;
// Ignore data from mouse.
if (stat & KBS_TERR)
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;
}
void
kbd_intr(void)
{
cons_intr(kbd_proc_data);
}
static void
kbd_init(void)
{
}
/***** General device-independent console code *****/
// 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;
// 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)
continue;
cons.buf[cons.wpos++] = c;
if (cons.wpos == CONSBUFSIZE)
cons.wpos = 0;
}
}
// return the next input character from the console, or 0 if none waiting
int
cons_getc(void)
{
int c;
// 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;
return c;
}
return 0;
}
// output a character to the console
static void
cons_putc(int c)
{
serial_putc(c);
lpt_putc(c);
cga_putc(c);
}
// initialize the console devices
void
cons_init(void)
{
cga_init();
kbd_init();
serial_init();
if (!serial_exists)
cprintf("Serial port does not exist!\n");
}
// `High'-level console I/O. Used by readline and cprintf.
void
cputchar(int c)
{
cons_putc(c);
}
int
getchar(void)
{
int c;
while ((c = cons_getc()) == 0)
/* do nothing */;
return c;
}
int
iscons(int fdnum)
{
// used by readline
return 1;
}
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