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
|
#include <stdio.h>
#include <stdlib.h>
typedef int int32_t;
struct cpu;
struct instr_call {
void (*f)(struct cpu *cpu, struct instr_call *ic);
/* int instr_len; */
void *arg[3];
};
struct cpu {
void *curpage;
int nloops;
struct instr_call *next_instr_call;
};
void r(struct cpu *cpu)
{
struct instr_call *ic;
for (;;) {
ic = cpu->next_instr_call++;
ic->f(cpu, ic);
ic = cpu->next_instr_call++;
ic->f(cpu, ic);
ic = cpu->next_instr_call++;
ic->f(cpu, ic);
ic = cpu->next_instr_call++;
ic->f(cpu, ic);
ic = cpu->next_instr_call++;
ic->f(cpu, ic);
ic = cpu->next_instr_call++;
ic->f(cpu, ic);
ic = cpu->next_instr_call++;
ic->f(cpu, ic);
ic = cpu->next_instr_call++;
ic->f(cpu, ic);
}
}
void f_add(struct cpu *cpu, struct instr_call *ic)
{
int32_t *a = (int32_t *) ic->arg[0];
int32_t *b = (int32_t *) ic->arg[1];
int32_t *c = (int32_t *) ic->arg[2];
*a = (*b) + (*c);
}
void f_end(struct cpu *cpu, struct instr_call *ic)
{
cpu->nloops--;
if (cpu->nloops > 0) {
cpu->next_instr_call = cpu->curpage;
return;
}
/* printf(" %i", cpu->nloops); fflush(stdout); */
printf("Exiting correctly\n");
exit(1);
}
int main(int argc, char *argv[])
{
int32_t tmp_a, tmp_b, tmp_c;
struct instr_call *call_array;
int i, ncalls;
struct cpu *cpu = malloc(sizeof(struct cpu));
if (argc <= 1) {
fprintf(stderr, "usage: %s n\n", argv[0]);
exit(1);
}
cpu->nloops = atoi(argv[1]);
ncalls = 1024 + 1;
/* Fill a range of nonsense calls: */
call_array = malloc(sizeof(struct instr_call) * ncalls);
cpu->curpage = call_array;
printf("ncalls = %i\n", ncalls);
for (i=0; i<ncalls; i++) {
if (i == ncalls-1) {
call_array[i].f = f_end;
} else {
call_array[i].f = f_add;
call_array[i].arg[0] = &tmp_a;
call_array[i].arg[1] = &tmp_b;
call_array[i].arg[2] = &tmp_c;
}
}
printf("running...\n");
cpu->next_instr_call = &call_array[0];
r(cpu);
printf("ERROR!\n");
return 0;
}
|
