1 #include <sys/types.h>
2 #include <sys/stat.h>
3 #include <sys/mman.h>
4 #include <stdbool.h>
5 #include <unistd.h>
6 #include <stdlib.h>
7 #include <string.h>
8 #include <fcntl.h>
9 #include <stdio.h>
10 #include <err.h>
11 
12 __attribute__((always_inline))
13 inline static void ebreak (void)
14 {
15 	__asm __volatile__ ("ebreak");
16 }
17 
18 __attribute__((always_inline))
19 inline static void *sys_brk (void *ptr)
20 {
21 	register void *a0 asm ("a0") = ptr;
22 	register int a7 asm ("a7") = 214;
23 	__asm __volatile__ ("ecall" : "=r"(a0) : "r"(a0), "r"(a7));
24 	return a0;
25 }
26 
27 unsigned mul(unsigned a, unsigned b)
28 {
29 	return a / b;
30 }
31 
32 int main (int argc, char *argv[]) {
33 	FILE *in, *out;
34 	int ch, *ptr;
35 
36 	ptr = malloc (4);
37 	*ptr = 1;
38 	free (ptr);
39 
40 	in = fopen ("/test.txt", "r");
41 	if (in == NULL)
42 		err (1, "open('test.txt')");
43 
44 	out = fopen ("/output.txt", "w");
45 	if (out == NULL)
46 		err (1, "open('output.txt')");
47 
48 	while ((ch = fgetc (in)) != EOF)
49 		fputc (ch, out);
50 
51 	fclose (out);
52 	fclose (in);
53 
54 	in = fopen ("/output.txt", "r");
55 	if (in == NULL)
56 		err (1, "reopen('output.txt')");
57 
58 	while ((ch = fgetc (in)) != EOF)
59 		putchar (ch);
60 
61 	fclose (in);
62 
63 	printf ("Result: %u\n", mul (3, 2));
64 
65 	execlp ("ksh", "ksh", NULL);
66 
67 	return 0;
68 }