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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 u32 div(u32 n, u32 d) // long division
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12 {
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13 u32 q=0, r=0;
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14 int i;
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15
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16 for(i=31;i>=0;i--){
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17 r = r << 1;
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18 r = r | ((n >> i) & 1);
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19 if(r >= d) {
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20 r = r - d;
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21 q = q | (1 << i);
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22 }
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23 }
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24 return q;
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25 }
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26
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27 static void
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28 printint(int fd, int xx, int base, int sgn)
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29 {
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30 static char digits[] = "0123456789ABCDEF";
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31 char buf[16];
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32 int i, neg;
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33 uint x, y, b;
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34
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35 neg = 0;
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36 if(sgn && xx < 0){
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37 neg = 1;
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38 x = -xx;
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39 } else {
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40 x = xx;
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41 }
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42
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43 b = base;
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44 i = 0;
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45 do{
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46 y = div(x, b);
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47 buf[i++] = digits[x - y * b];
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48 }while((x = y) != 0);
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49 if(neg)
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50 buf[i++] = '-';
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51
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52 while(--i >= 0)
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53 putc(fd, buf[i]);
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54 }
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55
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56 // Print to the given fd. Only understands %d, %x, %p, %s.
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57 void
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58 printf(int fd, char *fmt, ...)
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59 {
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60 char *s;
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61 int c, i, state;
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62 uint *ap;
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63
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64 state = 0;
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65 ap = (uint*)(void*)&fmt + 1;
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66 for(i = 0; fmt[i]; i++){
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67 c = fmt[i] & 0xff;
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68 if(state == 0){
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69 if(c == '%'){
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70 state = '%';
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71 } else {
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72 putc(fd, c);
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73 }
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74 } else if(state == '%'){
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75 if(c == 'd'){
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76 printint(fd, *ap, 10, 1);
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77 ap++;
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78 } else if(c == 'x' || c == 'p'){
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79 printint(fd, *ap, 16, 0);
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80 ap++;
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81 } else if(c == 's'){
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82 s = (char*)*ap;
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83 ap++;
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84 if(s == 0)
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85 s = "(null)";
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86 while(*s != 0){
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87 putc(fd, *s);
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88 s++;
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89 }
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90 } else if(c == 'c'){
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91 putc(fd, *ap);
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92 ap++;
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93 } else if(c == '%'){
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94 putc(fd, c);
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95 } else {
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96 // Unknown % sequence. Print it to draw attention.
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97 putc(fd, '%');
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98 putc(fd, c);
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99 }
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100 state = 0;
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101 }
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102 }
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103 }
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