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1 #include "types.h"
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2 #include "stat.h"
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3 #include "user.h"
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4
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5 static void
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6 putc(int fd, char c)
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7 {
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8 write(fd, &c, 1);
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9 }
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10
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11 static void
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12 printint(int fd, int xx, int base, int sgn)
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13 {
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14 static char digits[] = "0123456789ABCDEF";
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15 char buf[16];
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16 int i, neg;
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17 uint x;
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18
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19 neg = 0;
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20 if(sgn && xx < 0){
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21 neg = 1;
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22 x = -xx;
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23 } else {
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24 x = xx;
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25 }
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26
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27 i = 0;
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28 do{
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29 buf[i++] = digits[x % base];
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30 }while((x /= base) != 0);
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31 if(neg)
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32 buf[i++] = '-';
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33
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34 while(--i >= 0)
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35 putc(fd, buf[i]);
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36 }
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37
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38 // Print to the given fd. Only understands %d, %x, %p, %s.
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39 void
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40 printf(int fd, char *fmt, ...)
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41 {
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42 char *s;
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43 int c, i, state;
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44 uint *ap;
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45
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46 state = 0;
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47 ap = (uint*)(void*)&fmt + 1;
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48 for(i = 0; fmt[i]; i++){
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49 c = fmt[i] & 0xff;
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50 if(state == 0){
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51 if(c == '%'){
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52 state = '%';
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53 } else {
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54 putc(fd, c);
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55 }
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56 } else if(state == '%'){
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57 if(c == 'd'){
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58 printint(fd, *ap, 10, 1);
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59 ap++;
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60 } else if(c == 'x' || c == 'p'){
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61 printint(fd, *ap, 16, 0);
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62 ap++;
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63 } else if(c == 's'){
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64 s = (char*)*ap;
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65 ap++;
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66 if(s == 0)
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67 s = "(null)";
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68 while(*s != 0){
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69 putc(fd, *s);
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70 s++;
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71 }
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72 } else if(c == 'c'){
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73 putc(fd, *ap);
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74 ap++;
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75 } else if(c == '%'){
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76 putc(fd, c);
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77 } else {
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78 // Unknown % sequence. Print it to draw attention.
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79 putc(fd, '%');
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80 putc(fd, c);
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81 }
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82 state = 0;
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83 }
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84 }
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85 }
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