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
|
#include "types.h"
#include "param.h"
#include "mmu.h"
#include "proc.h"
#include "defs.h"
#include "x86.h"
#include "traps.h"
#include "syscall.h"
extern char edata[], end[];
int
main()
{
struct proc *p;
int i;
// clear BSS
memset(edata, 0, end - edata);
// partially initizialize PIC
outb(0x20+1, 0xFF); // IO_PIC1
outb(0xA0+1, 0xFF); // IO_PIC2
outb(0x20, 0x11);
outb(0x20+1, 32);
cprintf("\nxV6\n\n");
kinit(); // physical memory allocator
tinit(); // traps and interrupts
// create fake process zero
p = &proc[0];
curproc = p;
p->state = WAITING;
p->sz = PAGE;
p->mem = kalloc(p->sz);
memset(p->mem, 0, p->sz);
p->kstack = kalloc(KSTACKSIZE);
p->tf = (struct Trapframe *) (p->kstack + KSTACKSIZE - sizeof(struct Trapframe));
memset(p->tf, 0, sizeof(struct Trapframe));
p->tf->tf_es = p->tf->tf_ds = p->tf->tf_ss = (SEG_UDATA << 3) | 3;
p->tf->tf_cs = (SEG_UCODE << 3) | 3;
p->tf->tf_eflags = FL_IF;
setupsegs(p);
p = newproc();
i = 0;
p->mem[i++] = 0x90; // nop
p->mem[i++] = 0xb8; // mov ..., %eax
p->mem[i++] = SYS_fork;
p->mem[i++] = 0;
p->mem[i++] = 0;
p->mem[i++] = 0;
p->mem[i++] = 0xcd; // int
p->mem[i++] = T_SYSCALL;
p->mem[i++] = 0xb8; // mov ..., %eax
p->mem[i++] = SYS_exit;
p->mem[i++] = 0;
p->mem[i++] = 0;
p->mem[i++] = 0;
p->mem[i++] = 0xcd; // int
p->mem[i++] = T_SYSCALL;
p->tf->tf_eip = 0;
p->tf->tf_esp = p->sz;
swtch();
return 0;
}
|
