哈工大操作系统实验 6 字符显示的控制

这次试验相当简单，没啥好说的

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1.按下F12后，调用了keyboard.c中call show_stat，show_stat在sched.c中它又调用了show_task()函数，打印了当前进程的一些信息。
2.不影响到文件的输出，console.c中con_write函数实现的，这个文件是实现控制台输入输出模块的，所以不会影响对于文件的读写。想要影响到文件需要修改file_write函数。

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linux-0.11/kernel/chr_drv/keyboard.S

注释掉214行的

call show_stat

linux-0.11/kernel/chr_drv/tty_io.c

修改了copy_to_cooked函数

/* *  linux/kernel/tty_io.c * *  (C) 1991  Linus Torvalds *//* * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles * or rs-channels. It also implements echoing, cooked mode etc. * * Kill-line thanks to John T Kohl. */#include <ctype.h>#include <errno.h>#include <signal.h>#define ALRMMASK (1<<(SIGALRM-1))#define KILLMASK (1<<(SIGKILL-1))#define INTMASK (1<<(SIGINT-1))#define QUITMASK (1<<(SIGQUIT-1))#define TSTPMASK (1<<(SIGTSTP-1))#include <linux/sched.h>#include <linux/tty.h>#include <asm/segment.h>#include <asm/system.h>#define _L_FLAG(tty,f)((tty)->termios.c_lflag & f)#define _I_FLAG(tty,f)((tty)->termios.c_iflag & f)#define _O_FLAG(tty,f)((tty)->termios.c_oflag & f)#define L_CANON(tty)_L_FLAG((tty),ICANON)#define L_ISIG(tty)_L_FLAG((tty),ISIG)#define L_ECHO(tty)_L_FLAG((tty),ECHO)#define L_ECHOE(tty)_L_FLAG((tty),ECHOE)#define L_ECHOK(tty)_L_FLAG((tty),ECHOK)#define L_ECHOCTL(tty)_L_FLAG((tty),ECHOCTL)#define L_ECHOKE(tty)_L_FLAG((tty),ECHOKE)#define I_UCLC(tty)_I_FLAG((tty),IUCLC)#define I_NLCR(tty)_I_FLAG((tty),INLCR)#define I_CRNL(tty)_I_FLAG((tty),ICRNL)#define I_NOCR(tty)_I_FLAG((tty),IGNCR)#define O_POST(tty)_O_FLAG((tty),OPOST)#define O_NLCR(tty)_O_FLAG((tty),ONLCR)#define O_CRNL(tty)_O_FLAG((tty),OCRNL)#define O_NLRET(tty)_O_FLAG((tty),ONLRET)#define O_LCUC(tty)_O_FLAG((tty),OLCUC)struct tty_struct tty_table[] = {{{ICRNL,/* change incoming CR to NL */OPOST|ONLCR,/* change outgoing NL to CRNL */0,ISIG | ICANON | ECHO | ECHOCTL | ECHOKE,0,/* console termio */INIT_C_CC},0,/* initial pgrp */0,/* initial stopped */con_write,{0,0,0,0,""},/* console read-queue */{0,0,0,0,""},/* console write-queue */{0,0,0,0,""}/* console secondary queue */},{{0, /* no translation */0,  /* no translation */B2400 | CS8,0,0,INIT_C_CC},0,0,rs_write,{0x3f8,0,0,0,""},/* rs 1 */{0x3f8,0,0,0,""},{0,0,0,0,""}},{{0, /* no translation */0,  /* no translation */B2400 | CS8,0,0,INIT_C_CC},0,0,rs_write,{0x2f8,0,0,0,""},/* rs 2 */{0x2f8,0,0,0,""},{0,0,0,0,""}}};/* * these are the tables used by the machine code handlers. * you can implement pseudo-tty's or something by changing * them. Currently not done. */struct tty_queue * table_list[]={&tty_table[0].read_q, &tty_table[0].write_q,&tty_table[1].read_q, &tty_table[1].write_q,&tty_table[2].read_q, &tty_table[2].write_q};void tty_init(void){rs_init();con_init();}void tty_intr(struct tty_struct * tty, int mask){int i;if (tty->pgrp <= 0)return;for (i=0;i<NR_TASKS;i++)if (task[i] && task[i]->pgrp==tty->pgrp)task[i]->signal |= mask;}static void sleep_if_empty(struct tty_queue * queue){cli();while (!current->signal && EMPTY(*queue))interruptible_sleep_on(&queue->proc_list);sti();}static void sleep_if_full(struct tty_queue * queue){if (!FULL(*queue))return;cli();while (!current->signal && LEFT(*queue)<128)interruptible_sleep_on(&queue->proc_list);sti();}void wait_for_keypress(void){sleep_if_empty(&tty_table[0].secondary);}void copy_to_cooked(struct tty_struct * tty){        signed char c;        while (!EMPTY(tty->read_q) && !FULL(tty->secondary)) {                GETCH(tty->read_q,c);                if (c=='L'){                        if (judge) judge=0;                        else judge=1;                        break;                }if (c==13)if (I_CRNL(tty))c=10;else if (I_NOCR(tty))continue;else ;else if (c==10 && I_NLCR(tty))c=13;if (I_UCLC(tty))c=tolower(c);if (L_CANON(tty)) {if (c==KILL_CHAR(tty)) {/* deal with killing the input line */while(!(EMPTY(tty->secondary) ||        (c=LAST(tty->secondary))==10 ||        c==EOF_CHAR(tty))) {if (L_ECHO(tty)) {if (c<32)PUTCH(127,tty->write_q);PUTCH(127,tty->write_q);tty->write(tty);}DEC(tty->secondary.head);}continue;}if (c==ERASE_CHAR(tty)) {if (EMPTY(tty->secondary) ||   (c=LAST(tty->secondary))==10 ||   c==EOF_CHAR(tty))continue;if (L_ECHO(tty)) {if (c<32)PUTCH(127,tty->write_q);PUTCH(127,tty->write_q);tty->write(tty);}DEC(tty->secondary.head);continue;}if (c==STOP_CHAR(tty)) {tty->stopped=1;continue;}if (c==START_CHAR(tty)) {tty->stopped=0;continue;}}if (L_ISIG(tty)) {if (c==INTR_CHAR(tty)) {tty_intr(tty,INTMASK);continue;}if (c==QUIT_CHAR(tty)) {tty_intr(tty,QUITMASK);continue;}}if (c==10 || c==EOF_CHAR(tty))tty->secondary.data++;if (L_ECHO(tty)) {if (c==10) {PUTCH(10,tty->write_q);PUTCH(13,tty->write_q);} else if (c<32) {if (L_ECHOCTL(tty)) {PUTCH('^',tty->write_q);PUTCH(c+64,tty->write_q);}} elsePUTCH(c,tty->write_q);tty->write(tty);}PUTCH(c,tty->secondary);}wake_up(&tty->secondary.proc_list);}int tty_read(unsigned channel, char * buf, int nr){struct tty_struct * tty;char c, * b=buf;int minimum,time,flag=0;long oldalarm;if (channel>2 || nr<0) return -1;tty = &tty_table[channel];oldalarm = current->alarm;time = 10L*tty->termios.c_cc[VTIME];minimum = tty->termios.c_cc[VMIN];if (time && !minimum) {minimum=1;if ((flag=(!oldalarm || time+jiffies<oldalarm)))current->alarm = time+jiffies;}if (minimum>nr)minimum=nr;while (nr>0) {if (flag && (current->signal & ALRMMASK)) {current->signal &= ~ALRMMASK;break;}if (current->signal)break;if (EMPTY(tty->secondary) || (L_CANON(tty) &&!tty->secondary.data && LEFT(tty->secondary)>20)) {sleep_if_empty(&tty->secondary);continue;}do {GETCH(tty->secondary,c);if (c==EOF_CHAR(tty) || c==10)tty->secondary.data--;if (c==EOF_CHAR(tty) && L_CANON(tty))return (b-buf);else {put_fs_byte(c,b++);if (!--nr)break;}} while (nr>0 && !EMPTY(tty->secondary));if (time && !L_CANON(tty)) {if ((flag=(!oldalarm || time+jiffies<oldalarm)))current->alarm = time+jiffies;elsecurrent->alarm = oldalarm;}if (L_CANON(tty)) {if (b-buf)break;} else if (b-buf >= minimum)break;}current->alarm = oldalarm;if (current->signal && !(b-buf))return -EINTR;return (b-buf);}int tty_write(unsigned channel, char * buf, int nr){static int cr_flag=0;struct tty_struct * tty;char c, *b=buf;if (channel>2 || nr<0) return -1;tty = channel + tty_table;while (nr>0) {sleep_if_full(&tty->write_q);if (current->signal)break;while (nr>0 && !FULL(tty->write_q)) {c=get_fs_byte(b);if (O_POST(tty)) {if (c=='\r' && O_CRNL(tty))c='\n';else if (c=='\n' && O_NLRET(tty))c='\r';if (c=='\n' && !cr_flag && O_NLCR(tty)) {cr_flag = 1;PUTCH(13,tty->write_q);continue;}if (O_LCUC(tty))c=toupper(c);}b++; nr--;cr_flag = 0;PUTCH(c,tty->write_q);}tty->write(tty);if (nr>0)schedule();}return (b-buf);}/* * Jeh, sometimes I really like the 386. * This routine is called from an interrupt, * and there should be absolutely no problem * with sleeping even in an interrupt (I hope). * Of course, if somebody proves me wrong, I'll * hate intel for all time :-). We'll have to * be careful and see to reinstating the interrupt * chips before calling this, though. * * I don't think we sleep here under normal circumstances * anyway, which is good, as the task sleeping might be * totally innocent. */void do_tty_interrupt(int tty){copy_to_cooked(tty_table+tty);}void chr_dev_init(void){}

linux-0.11/kernel/chr_drv/tty_io.c

修改了con_write函数

/* *  linux/kernel/console.c * *  (C) 1991  Linus Torvalds *//* *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. * * Beeping thanks to John T Kohl. *//* *  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. *//* * Code to check for different video-cards mostly by Galen Hunt, * <[e-mail]> */#include <linux/sched.h>#include <linux/tty.h>#include <asm/io.h>#include <asm/system.h>/* * These are set up by the setup-routine at boot-time: */#define ORIG_X(*(unsigned char *)0x90000)#define ORIG_Y(*(unsigned char *)0x90001)#define ORIG_VIDEO_PAGE(*(unsigned short *)0x90004)#define ORIG_VIDEO_MODE((*(unsigned short *)0x90006) & 0xff)#define ORIG_VIDEO_COLS (((*(unsigned short *)0x90006) & 0xff00) >> 8)#define ORIG_VIDEO_LINES(25)#define ORIG_VIDEO_EGA_AX(*(unsigned short *)0x90008)#define ORIG_VIDEO_EGA_BX(*(unsigned short *)0x9000a)#define ORIG_VIDEO_EGA_CX(*(unsigned short *)0x9000c)#define VIDEO_TYPE_MDA0x10/* Monochrome Text Display*/#define VIDEO_TYPE_CGA0x11/* CGA Display */#define VIDEO_TYPE_EGAM0x20/* EGA/VGA in Monochrome Mode*/#define VIDEO_TYPE_EGAC0x21/* EGA/VGA in Color Mode*/#define NPAR 16extern void keyboard_interrupt(void);static unsigned charvideo_type;/* Type of display being used*/static unsigned longvideo_num_columns;/* Number of text columns*/static unsigned longvideo_size_row;/* Bytes per row*/static unsigned longvideo_num_lines;/* Number of test lines*/static unsigned charvideo_page;/* Initial video page*/static unsigned longvideo_mem_start;/* Start of video RAM*/static unsigned longvideo_mem_end;/* End of video RAM (sort of)*/static unsigned shortvideo_port_reg;/* Video register select port*/static unsigned shortvideo_port_val;/* Video register value port*/static unsigned shortvideo_erase_char;/* Char+Attrib to erase with*/static unsigned longorigin;/* Used for EGA/VGA fast scroll*/static unsigned longscr_end;/* Used for EGA/VGA fast scroll*/static unsigned longpos;static unsigned longx,y;static unsigned longtop,bottom;static unsigned longstate=0;static unsigned longnpar,par[NPAR];static unsigned longques=0;static unsigned charattr=0x07;static void sysbeep(void);/* * this is what the terminal answers to a ESC-Z or csi0c * query (= vt100 response). */#define RESPONSE "\033[?1;2c"/* NOTE! gotoxy thinks x==video_num_columns is ok */static inline void gotoxy(unsigned int new_x,unsigned int new_y){if (new_x > video_num_columns || new_y >= video_num_lines)return;x=new_x;y=new_y;pos=origin + y*video_size_row + (x<<1);}static inline void set_origin(void){cli();outb_p(12, video_port_reg);outb_p(0xff&((origin-video_mem_start)>>9), video_port_val);outb_p(13, video_port_reg);outb_p(0xff&((origin-video_mem_start)>>1), video_port_val);sti();}static void scrup(void){if (video_type == VIDEO_TYPE_EGAC || video_type == VIDEO_TYPE_EGAM){if (!top && bottom == video_num_lines) {origin += video_size_row;pos += video_size_row;scr_end += video_size_row;if (scr_end > video_mem_end) {__asm__("cld\n\t""rep\n\t""movsl\n\t""movl video_num_columns,%1\n\t""rep\n\t""stosw"::"a" (video_erase_char),"c" ((video_num_lines-1)*video_num_columns>>1),"D" (video_mem_start),"S" (origin));scr_end -= origin-video_mem_start;pos -= origin-video_mem_start;origin = video_mem_start;} else {__asm__("cld\n\t""rep\n\t""stosw"::"a" (video_erase_char),"c" (video_num_columns),"D" (scr_end-video_size_row));}set_origin();} else {__asm__("cld\n\t""rep\n\t""movsl\n\t""movl video_num_columns,%%ecx\n\t""rep\n\t""stosw"::"a" (video_erase_char),"c" ((bottom-top-1)*video_num_columns>>1),"D" (origin+video_size_row*top),"S" (origin+video_size_row*(top+1)));}}else/* Not EGA/VGA */{__asm__("cld\n\t""rep\n\t""movsl\n\t""movl video_num_columns,%%ecx\n\t""rep\n\t""stosw"::"a" (video_erase_char),"c" ((bottom-top-1)*video_num_columns>>1),"D" (origin+video_size_row*top),"S" (origin+video_size_row*(top+1)));}}static void scrdown(void){if (video_type == VIDEO_TYPE_EGAC || video_type == VIDEO_TYPE_EGAM){__asm__("std\n\t""rep\n\t""movsl\n\t""addl $2,%%edi\n\t"/* %edi has been decremented by 4 */"movl video_num_columns,%%ecx\n\t""rep\n\t""stosw"::"a" (video_erase_char),"c" ((bottom-top-1)*video_num_columns>>1),"D" (origin+video_size_row*bottom-4),"S" (origin+video_size_row*(bottom-1)-4));}else/* Not EGA/VGA */{__asm__("std\n\t""rep\n\t""movsl\n\t""addl $2,%%edi\n\t"/* %edi has been decremented by 4 */"movl video_num_columns,%%ecx\n\t""rep\n\t""stosw"::"a" (video_erase_char),"c" ((bottom-top-1)*video_num_columns>>1),"D" (origin+video_size_row*bottom-4),"S" (origin+video_size_row*(bottom-1)-4));}}static void lf(void){if (y+1<bottom) {y++;pos += video_size_row;return;}scrup();}static void ri(void){if (y>top) {y--;pos -= video_size_row;return;}scrdown();}static void cr(void){pos -= x<<1;x=0;}static void del(void){if (x) {pos -= 2;x--;*(unsigned short *)pos = video_erase_char;}}static void csi_J(int par){long count;long start;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 = video_num_columns * video_num_lines;start = origin;break;default:return;}__asm__("cld\n\t""rep\n\t""stosw\n\t"::"c" (count),"D" (start),"a" (video_erase_char));}static void csi_K(int par){long count;long start;switch (par) {case 0:/* erase from cursor to end of line */if (x>=video_num_columns)return;count = video_num_columns-x;start = pos;break;case 1:/* erase from start of line to cursor */start = pos - (x<<1);count = (x<video_num_columns)?x:video_num_columns;break;case 2: /* erase whole line */start = pos - (x<<1);count = video_num_columns;break;default:return;}__asm__("cld\n\t""rep\n\t""stosw\n\t"::"c" (count),"D" (start),"a" (video_erase_char));}void csi_m(void){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();outb_p(14, video_port_reg);outb_p(0xff&((pos-video_mem_start)>>9), video_port_val);outb_p(15, video_port_reg);outb_p(0xff&((pos-video_mem_start)>>1), video_port_val);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);}static void insert_char(void){int i=x;unsigned short tmp, old = video_erase_char;unsigned short * p = (unsigned short *) pos;while (i++<video_num_columns) {tmp=*p;*p=old;old=tmp;p++;}}static void insert_line(void){int oldtop,oldbottom;oldtop=top;oldbottom=bottom;top=y;bottom = video_num_lines;scrdown();top=oldtop;bottom=oldbottom;}static void delete_char(void){int i;unsigned short * p = (unsigned short *) pos;if (x>=video_num_columns)return;i = x;while (++i < video_num_columns) {*p = *(p+1);p++;}*p = video_erase_char;}static void delete_line(void){int oldtop,oldbottom;oldtop=top;oldbottom=bottom;top=y;bottom = video_num_lines;scrup();top=oldtop;bottom=oldbottom;}static void csi_at(unsigned int nr){if (nr > video_num_columns)nr = video_num_columns;else if (!nr)nr = 1;while (nr--)insert_char();}static void csi_L(unsigned int nr){if (nr > video_num_lines)nr = video_num_lines;else if (!nr)nr = 1;while (nr--)insert_line();}static void csi_P(unsigned int nr){if (nr > video_num_columns)nr = video_num_columns;else if (!nr)nr = 1;while (nr--)delete_char();}static void csi_M(unsigned int nr){if (nr > video_num_lines)nr = video_num_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){gotoxy(saved_x, saved_y);}void con_write(struct tty_struct * tty){        int nr;        char c;        nr = CHARS(tty->write_q);        while (nr--) {                GETCH(tty->write_q,c);                if(judge){                        if((c>='a'&&c<='z')||(c>='A'&&c<='Z')||(c>='0'&&c<='9'))                        c=42;                }switch(state) {case 0:if (c>31 && c<127) {if (x>=video_num_columns) {x -= video_num_columns;pos -= video_size_row;lf();}__asm__("movb attr,%%ah\n\t""movw %%ax,%1\n\t"::"a" (c),"m" (*(short *)pos));pos += 2;x++;} else if (c==27)state=1;else if (c==10 || c==11 || c==12)lf();else if (c==13)cr();else if (c==ERASE_CHAR(tty))del();else if (c==8) {if (x) {x--;pos -= 2;}} else if (c==9) {c=8-(x&7);x += c;pos += c<<1;if (x>video_num_columns) {x -= video_num_columns;pos -= video_size_row;lf();}c=9;} else if (c==7)sysbeep();break;case 1:state=0;if (c=='[')state=2;else if (c=='E')gotoxy(0,y+1);else if (c=='M')ri();else if (c=='D')lf();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: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] = video_num_lines;if (par[0] < par[1] &&    par[1] <= video_num_lines) {top=par[0];bottom=par[1];}break;case 's':save_cur();break;case 'u':restore_cur();break;}}}set_cursor();}/* *  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. * * Reads the information preserved by setup.s to determine the current display * type and sets everything accordingly. */void con_init(void){register unsigned char a;char *display_desc = "????";char *display_ptr;video_num_columns = ORIG_VIDEO_COLS;video_size_row = video_num_columns * 2;video_num_lines = ORIG_VIDEO_LINES;video_page = ORIG_VIDEO_PAGE;video_erase_char = 0x0720;if (ORIG_VIDEO_MODE == 7)/* Is this a monochrome display? */{video_mem_start = 0xb0000;video_port_reg = 0x3b4;video_port_val = 0x3b5;if ((ORIG_VIDEO_EGA_BX & 0xff) != 0x10){video_type = VIDEO_TYPE_EGAM;video_mem_end = 0xb8000;display_desc = "EGAm";}else{video_type = VIDEO_TYPE_MDA;video_mem_end= 0xb2000;display_desc = "*MDA";}}else/* If not, it is color. */{video_mem_start = 0xb8000;video_port_reg= 0x3d4;video_port_val= 0x3d5;if ((ORIG_VIDEO_EGA_BX & 0xff) != 0x10){video_type = VIDEO_TYPE_EGAC;video_mem_end = 0xbc000;display_desc = "EGAc";}else{video_type = VIDEO_TYPE_CGA;video_mem_end = 0xba000;display_desc = "*CGA";}}/* Let the user known what kind of display driver we are using */display_ptr = ((char *)video_mem_start) + video_size_row - 8;while (*display_desc){*display_ptr++ = *display_desc++;display_ptr++;}/* Initialize the variables used for scrolling (mostly EGA/VGA)*/origin= video_mem_start;scr_end= video_mem_start + video_num_lines * video_size_row;top= 0;bottom= video_num_lines;gotoxy(ORIG_X,ORIG_Y);set_trap_gate(0x21,&keyboard_interrupt);outb_p(inb_p(0x21)&0xfd,0x21);a=inb_p(0x61);outb_p(a|0x80,0x61);outb(a,0x61);}/* from bsd-net-2: */void sysbeepstop(void){/* disable counter 2 */outb(inb_p(0x61)&0xFC, 0x61);}int beepcount = 0;static void sysbeep(void){/* enable counter 2 */outb_p(inb_p(0x61)|3, 0x61);/* set command for counter 2, 2 byte write */outb_p(0xB6, 0x43);/* send 0x637 for 750 HZ */outb_p(0x37, 0x42);outb(0x06, 0x42);/* 1/8 second */beepcount = HZ/8;}

linux-0.11/include/asm/system.h

声明一个变量 int  judge 

int judge;#define move_to_user_mode() \...