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#include <stdlib.h>
#include <stdio.h>
//printf needs following syscalls: sbrk write close fstat isatty lseek read
//
#include <sys/stat.h>
int close(int file)
{
return -1;
}
int fstat(int file, struct stat *st)
{
st->st_mode = S_IFCHR;
return 0;
}
int isatty(int file) {
return 1;
}
int lseek(int file, int ptr, int dir) {
return 0;
}
int read(int file, char *ptr, int len) {
return 0;
}
int write(int file, char *ptr, int len)
{
int todo;
for (todo = 0; todo < len; todo++)
{
char byte=(*ptr++);
int byt=byte;
int ebx; // will hold return value;
// system call
asm("pusha");
asm("mov $61,%eax"); // select syscall)
asm("mov %0,%%edx"::"m"(byt));
//asm("mov $88,%edx");
asm("int $0x80"); // actual syscall ! interrupt
asm("mov %%ebx, %0": "=b" (ebx));
asm("popa");
//
}
return len;
}
caddr_t sbrk(int incr)
{
// extern char _end; /* Defined by the linker */
char _end;
static char *heap_end;
char *prev_heap_end;
if (heap_end == 0) {
heap_end = &_end;
}
prev_heap_end = heap_end;
/*
if (heap_end + incr > stack_ptr) {
write (1, "Heap and stack collision\n", 25);
abort ();
}
*/
heap_end += incr;
return (caddr_t) prev_heap_end;
}
//
int main()
{
int x=atoi("33");
int *mem=0x80000;
int *mem2=0x80010;
int y=0;
*mem=x;
while(1)
{
printf("test printf");
// write(1,"dupa",4);
// y=example_call();
y++;
*mem2=y;
}
}
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