1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
|
//
// formatted console output -- printf, panic.
//
// TODO Printf to not use mul/div/mod and all that and send stuff to hw-implemented UART
#include <stdarg.h>
#include "types.h"
#include "param.h"
#include "spinlock.h"
#include "sleeplock.h"
#include "fs.h"
#include "file.h"
#include "memlayout.h"
#include "riscv.h"
#include "defs.h"
#include "proc.h"
volatile int panicked = 0;
// lock to avoid interleaving concurrent printf's.
static struct {
struct spinlock lock;
int locking;
} pr;
static char digits[] = "0123456789abcdef";
int mul(int x, int y)
{
int ret = x;
for (int tmp = y-1; tmp > 0; tmp--) {
// Add higher and lower 16 bits seperately
// apparently gcc uses muldi3 builtin while adding long long ints
int rettmp = ret;
ret = (((uint16)(x>>16))+((uint16)(rettmp>>16)));
ret += (((uint16)(x&0xffff))+((uint16)(rettmp&0xffff)));
}
return ret;
}
int mod(int x, int y)
{
int idx = 0;
for (idx = 0; mul(idx, y) <= x; idx++);
idx = x-mul((idx-1), y);
return idx;
}
int div(int x, int y)
{
if (y >= x)
return 0;
int ret = 1;
for (; (x=x-y) >= y; ret++);
return ret;
}
static void
printint(int xx, int base, int sign)
{
char buf[16];
int i;
uint x;
if(sign && (sign = xx < 0))
x = -xx;
else
x = xx;
i = 0;
do {
buf[i++] = digits[mod(x, base)];
x = div(x, base);
} while(x != 0);
if(sign)
buf[i++] = '-';
while(--i >= 0)
consputc(buf[i]);
}
static void
printptr(uint64 x)
{
int i;
consputc('0');
consputc('x');
for (i = 0; i < (mul(sizeof(uint64), 2)); i++, x <<= 4)
consputc(digits[x >> (mul(sizeof(uint64), 8) - 4)]);
}
// Print to the console. only understands %d, %x, %p, %s.
void
printf(char *fmt, ...)
{
va_list ap;
int i, c, locking;
char *s;
locking = pr.locking;
if(locking)
acquire(&pr.lock);
if (fmt == 0)
panic("null fmt");
va_start(ap, fmt);
for(i = 0; (c = fmt[i] & 0xff) != 0; i++){
if(c != '%'){
consputc(c);
continue;
}
c = fmt[++i] & 0xff;
if(c == 0)
break;
switch(c){
case 'd':
printint(va_arg(ap, int), 10, 1);
break;
case 'x':
printint(va_arg(ap, int), 16, 1);
break;
case 'p':
printptr(va_arg(ap, uint64));
break;
case 's':
if((s = va_arg(ap, char*)) == 0)
s = "(null)";
for(; *s; s++)
consputc(*s);
break;
case '%':
consputc('%');
break;
default:
// Print unknown % sequence to draw attention.
consputc('%');
consputc(c);
break;
}
}
if(locking)
release(&pr.lock);
}
void
panic(char *s)
{
pr.locking = 0;
printf("panic: ");
printf(s);
printf("\n");
panicked = 1; // freeze uart output from other CPUs
for(;;)
;
}
void
printfinit(void)
{
initlock(&pr.lock, "pr");
pr.locking = 1;
}
|
