?? console.c
字號:
/*
* console.c
*
* This module implements the console io functions
* 'void con_init(void)'
* 'void con_write(struct tty_queue * queue)'
* Hopefully this will be a rather complete VT102 implementation.
*
*/
/*
* NOTE!!! We sometimes disable and enable interrupts for a short while
* (to put a word in video IO), but this will work even for keyboard
* interrupts. We know interrupts aren't enabled when getting a keyboard
* interrupt, as we use trap-gates. Hopefully all is well.
*/
#include <linux/sched.h>
#include <linux/tty.h>
#include <asm/io.h>
#include <asm/system.h>
#define SCREEN_START 0xb8000 //0Xb8000---0XbFFFF是顯存的地址
#define SCREEN_END 0xc0000
#define LINES 25
#define COLUMNS 80
#define NPAR 16
extern void keyboard_interrupt(void);
static unsigned long origin=SCREEN_START;
static unsigned long scr_end=SCREEN_START+LINES*COLUMNS*2;
static unsigned long pos;
static unsigned long x,y;
static unsigned long top=0,bottom=LINES;
static unsigned long lines=LINES,columns=COLUMNS;
static unsigned long state=0;
static unsigned long npar,par[NPAR];
static unsigned long ques=0;
static unsigned char attr=0x07;
/*
* this is what the terminal answers to a ESC-Z or csi0c
* query (= vt100 response).
*/
#define RESPONSE "\033[?1;2c" //\033=0X1B=ESC鍵
static inline void gotoxy(unsigned int new_x,unsigned int new_y)
{
if (new_x>=columns || new_y>=lines)
return;
x=new_x;
y=new_y;
pos=origin+((y*columns+x)<<1); //乘2是因為描述位置是字
}
static inline void set_origin(void)
{
cli();
//下面二個寄存器處理屏幕滾動，寄存器12是開始地址的高字，13是低字
//0x3d4是6845索引寄存器，它可以選擇18個寄存器，但必須在讀/寫0x3d5之前，18個寄存器中前10個是處理垂直和水平顯示參數(shù)的，不要動
outb_p(12,0x3d4);
outb_p(0xff&((origin-SCREEN_START)>>9),0x3d5);
outb_p(13,0x3d4);
outb_p(0xff&((origin-SCREEN_START)>>1),0x3d5);
sti();
}
static void scrup(void)
{
if (!top && bottom==lines) {
origin += columns<<1;
pos += columns<<1;
scr_end += columns<<1;
if (scr_end>SCREEN_END) {
//以下的內(nèi)嵌匯編意思是：
// movl 0X0720 %eax //其中0X0720中的07表示屬性為灰，20代表空白鍵
// movl (line-1)*columns>>1 %ecx
// movl SCREEN_START %edi
// movl origin %esi
// cld //地址增量
// rep movsl //ds:si --->es:di
// movl _columns %ecx
// rep stosw //將eax中的內(nèi)容傳入ES：DI中
__asm__("cld\n\t"
"rep\n\t"
"movsl\n\t"
"movl _columns,%1\n\t"
"rep\n\t"
"stosw"
::"a" (0x0720),
"c" ((lines-1)*columns>>1),
"D" (SCREEN_START),
"S" (origin)
:"cx","di","si");
scr_end -= origin-SCREEN_START;
pos -= origin-SCREEN_START;
origin = SCREEN_START;
} else {
//以下的內(nèi)嵌匯編意思是：
// movl 0X07200720 %eax
// movl columns>>1 %ecx //因為傳送的是雙字，所以要除2
// movl scr_end-(columns<<1) %edi
// cld
// rep stosl //雙字傳送
__asm__("cld\n\t"
"rep\n\t"
"stosl"
::"a" (0x07200720),
"c" (columns>>1),
"D" (scr_end-(columns<<1))
:"cx","di");
}
set_origin();
} else {
//以下的內(nèi)嵌匯編意思是：
// movl 0X0720 %eax
// movl (bottom-top-1)*columns>>1 %ecx
// movl origin+(columns<<1)*top %edi
// movl origin+(columns<<1)*(top+1) %esi
// cld
// rep movsl
// movl _columns %ecx
// rep stosw
__asm__("cld\n\t"
"rep\n\t"
"movsl\n\t"
"movl _columns,%%ecx\n\t"
"rep\n\t"
"stosw"
::"a" (0x0720),
"c" ((bottom-top-1)*columns>>1),
"D" (origin+(columns<<1)*top),
"S" (origin+(columns<<1)*(top+1))
:"cx","di","si");
}
}
static void scrdown(void)
{
//以下的內(nèi)嵌匯編意思是：
// movl 0X0720 %eax
// movl (bottom-top-1)*columns %ecx
// movl (origin+(columns<<1)*(bottom-1)-4) %esi
// std //地址減量
// rep movsl
// addl $2 %%edi
// movl _columns %ecx
// stosw
__asm__("std\n\t"
"rep\n\t"
"movsl\n\t"
"addl $2,%%edi\n\t" /* %edi has been decremented by 4 */
"movl _columns,%%ecx\n\t"
"rep\n\t"
"stosw"
::"a" (0x0720),
"c" ((bottom-top-1)*columns>>1),
"D" (origin+(columns<<1)*bottom-4),
"S" (origin+(columns<<1)*(bottom-1)-4)
:"ax","cx","di","si");
}
static void lf(void)
{
if (y+1<bottom) {
y++;
pos += columns<<1;
return;
}
scrup(); //如果超過了底部，屏向上走一行
}
static void ri(void)
{
if (y>top) {
y--;
pos -= columns<<1;
return;
}
scrdown(); //如果y<top，就是超過了屏的頂部，就向下走一行
}
static void cr(void)
{
pos -= x<<1;
x=0;
}
static void del(void)
{
if (x) {
pos -= 2;
x--;
*(unsigned short *)pos = 0x0720; //將刪除的這個字填為空白，屬性為灰
}
}
static void csi_J(int par) //這是處理整個顯示區(qū)的擦除函數(shù)
{
long count __asm__("cx");
long start __asm__("di");
switch (par) {
case 0: /* erase from cursor to end of display */
count = (scr_end-pos)>>1;
start = pos;
break;
case 1: /* erase from start to cursor */
count = (pos-origin)>>1;
start = origin;
break;
case 2: /* erase whole display */
count = columns*lines;
start = origin;
break;
default:
return;
}
//以下的內(nèi)嵌匯編意思是：
// movl count %ecx
// movl start %edi
// movl 0X0720 %eax
// cld
// rep stosw
__asm__("cld\n\t"
"rep\n\t"
"stosw\n\t"
::"c" (count),
"D" (start),"a" (0x0720)
:"cx","di");
}
static void csi_K(int par)
{
long count __asm__("cx");
long start __asm__("di");
switch (par) {
case 0: /* erase from cursor to end of line */
if (x>=columns)
return;
count = columns-x;
start = pos;
break;
case 1: /* erase from start of line to cursor */
start = pos - (x<<1);
count = (x<columns)?x:columns;
break;
case 2: /* erase whole line */
start = pos - (x<<1);
count = columns;
break;
default:
return;
}
__asm__("cld\n\t" //同上
"rep\n\t"
"stosw\n\t"
::"c" (count),
"D" (start),"a" (0x0720)
:"cx","di");
}
void csi_m(void) //修改部分區(qū)域的字符屬性
{
int i;
for (i=0;i<=npar;i++)
switch (par[i]) {
case 0:attr=0x07;break;
case 1:attr=0x0f;break;
case 4:attr=0x0f;break;
case 7:attr=0x70;break;
case 27:attr=0x07;break;
}
}
static inline void set_cursor(void)
{
cli();
//寄存器14控制光標(biāo)位置（高位字），寄存器15控制低位字
outb_p(14,0x3d4);
outb_p(0xff&((pos-SCREEN_START)>>9),0x3d5);
outb_p(15,0x3d4);
outb_p(0xff&((pos-SCREEN_START)>>1),0x3d5);
sti();
}
static void respond(struct tty_struct * tty)
{
char * p = RESPONSE;
cli();
while (*p) {
PUTCH(*p,tty->read_q);
p++;
}
sti();
copy_to_cooked(tty); //此函數(shù)在tty_io.c中定義
}
static void insert_char(void)
{
int i=x;
unsigned short tmp,old=0x0720;
unsigned short * p = (unsigned short *) pos;
while (i++<columns) { //將光標(biāo)的當(dāng)前位置填空為0X0720，然后循環(huán)，把當(dāng)前位置的老的字符向后移，然后將后面的所有字符向后移一位置
tmp=*p;
*p=old;
old=tmp;
p++;
}
}
static void insert_line(void)
{
int oldtop,oldbottom;
oldtop=top;
oldbottom=bottom;
top=y; //top是當(dāng)前光標(biāo)位置的Y軸，即為當(dāng)前屏幕的第Y行
bottom=lines;
scrdown();
top=oldtop;
bottom=oldbottom;
}
static void delete_char(void)
{
int i;
unsigned short * p = (unsigned short *) pos;
if (x>=columns)
return;
i = x; //X為當(dāng)前光標(biāo)的X軸，即為當(dāng)前屏幕的X列
while (++i < columns) {
*p = *(p+1);
p++;
}
*p=0x0720; //將最后一個字符填為0X0720
}
static void delete_line(void)
{
int oldtop,oldbottom;
oldtop=top;
oldbottom=bottom;
top=y;
bottom=lines;
scrup();
top=oldtop;
bottom=oldbottom;
}
static void csi_at(int nr)
{
if (nr>columns)
nr=columns;
else if (!nr) //如果nr為0，那么nr=1，這樣是保證插入一個字符
nr=1;
while (nr--)
insert_char();
}
static void csi_L(int nr)
{
if (nr>lines)
nr=lines;
else if (!nr)
nr=1;
while (nr--)
insert_line();
}
static void csi_P(int nr)
{
if (nr>columns)
nr=columns;
else if (!nr)
nr=1;
while (nr--)
delete_char();
}
static void csi_M(int nr)
{
if (nr>lines)
nr=lines;
else if (!nr)
nr=1;
while (nr--)
delete_line();
}
static int saved_x=0;
static int saved_y=0;
static void save_cur(void)
{
saved_x=x;
saved_y=y;
}
static void restore_cur(void)
{
x=saved_x;
y=saved_y;
pos=origin+((y*columns+x)<<1); //還原光標(biāo)位置
}
void con_write(struct tty_struct * tty)
{
int nr;
char c;
nr = CHARS(tty->write_q); //tty->write_q中有多少沒有被處理的字符
while (nr--) {
GETCH(tty->write_q,c);
switch(state) { //state默認為0
case 0:
if (c>31 && c<127) { //是有效可寫字符？
if (x>=columns) { //需要換行嗎？
x -= columns; //將光標(biāo)X軸指向本行的行首
pos -= columns<<1;
lf(); //將光標(biāo)指向下一行
}
//下面內(nèi)嵌匯編的意思是：
// movl c %eax
// movb 0X70 %ah
// movw %ax *pos
__asm__("movb _attr,%%ah\n\t"
"movw %%ax,%1\n\t"
::"a" (c),"m" (*(short *)pos) //其中m表示操作數(shù)是內(nèi)存變量
:"ax");
pos += 2; //指向下一個位置
x++;
} else if (c==27) //27=0X1B，是否為ESC鍵
state=1;
else if (c==10 || c==11 || c==12)
lf();
else if (c==13) //13=0X0D，是否為ENTER鍵
cr();
else if (c==ERASE_CHAR(tty))
del();
else if (c==8) { //8是空白鍵（BACKSPACE）
if (x) {
x--;
pos -= 2;
}
} else if (c==9) { //TAB鍵
c=8-(x&7); //只能跳過最大8個字符
x += c;
pos += c<<1;
if (x>columns) {
x -= columns;
pos -= columns<<1;
lf();
}
c=9;
}
break;
case 1:
state=0;
if (c=='[')
state=2;
else if (c=='E')
gotoxy(0,y+1); //到下行的開頭位置
else if (c=='M')
ri(); //光標(biāo)到上行的當(dāng)前位置
else if (c=='D')
lf(); //光標(biāo)到下行的當(dāng)前位置
else if (c=='Z')
respond(tty);
else if (x=='7')
save_cur();
else if (x=='8')
restore_cur();
break;
case 2:
for(npar=0;npar<NPAR;npar++)
par[npar]=0;
npar=0;
state=3;
if (ques=(c=='?'))
break;
case 3:
if (c==';' && npar<NPAR-1) {
npar++;
break;
} else if (c>='0' && c<='9') {
par[npar]=10*par[npar]+c-'0';
break;
} else state=4;
case 4: //光標(biāo)控制
state=0;
switch(c) {
case 'G': case '`':
if (par[0]) par[0]--;
gotoxy(par[0],y);
break;
case 'A':
if (!par[0]) par[0]++;
gotoxy(x,y-par[0]);
break;
case 'B': case 'e':
if (!par[0]) par[0]++;
gotoxy(x,y+par[0]);
break;
case 'C': case 'a':
if (!par[0]) par[0]++;
gotoxy(x+par[0],y);
break;
case 'D':
if (!par[0]) par[0]++;
gotoxy(x-par[0],y);
break;
case 'E':
if (!par[0]) par[0]++;
gotoxy(0,y+par[0]);
break;
case 'F':
if (!par[0]) par[0]++;
gotoxy(0,y-par[0]);
break;
case 'd':
if (par[0]) par[0]--;
gotoxy(x,par[0]);
break;
case 'H': case 'f':
if (par[0]) par[0]--;
if (par[1]) par[1]--;
gotoxy(par[1],par[0]);
break;
case 'J':
csi_J(par[0]);
break;
case 'K':
csi_K(par[0]);
break;
case 'L':
csi_L(par[0]);
break;
case 'M':
csi_M(par[0]);
break;
case 'P':
csi_P(par[0]);
break;
case '@':
csi_at(par[0]);
break;
case 'm':
csi_m();
break;
case 'r':
if (par[0]) par[0]--;
if (!par[1]) par[1]=lines;
if (par[0] < par[1] &&
par[1] <= lines) {
top=par[0];
bottom=par[1];
}
break;
case 's':
save_cur();
break;
case 'u':
restore_cur();
break;
}
}
}
set_cursor(); //實際硬件處理光標(biāo)
}
/*
* void con_init(void);
*
* This routine initalizes console interrupts, and does nothing
* else. If you want the screen to clear, call tty_write with
* the appropriate escape-sequece.
*/
void con_init(void)
{
register unsigned char a;
gotoxy(*(unsigned char *)(0x90000+510),*(unsigned char *)(0x90000+511)); //其中0X90000+510是在boot.s中已將光標(biāo)X、Y保存在0X90000+510處
set_trap_gate(0x21,&keyboard_interrupt); //定義IDT[21]中斷號是鍵盤中斷處理程序，鍵盤中斷處理程序在keyboard.s中
outb_p(inb_p(0x21)&0xfd,0x21); //屏蔽IRQ1
a=inb_p(0x61);
outb_p(a|0x80,0x61); //禁止端口60H開關(guān)，開放鍵盤數(shù)據(jù)，允許鍵盤IRQ
outb(a,0x61); //恢復(fù)
}
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