The code is doing the following:
for (;;) // while(true)
*(int32 *) 0 = 0; // Treat 0 as an address, de-reference the 0 address and try and store 0 into it.
This should segfault, null pointer de-reference.
EDIT
Compiled and ran for further information:
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
int main(void){
*(int32_t *) 0 = 0;
printf("done\n");
return 0;
}
gcc -g null.c; ./a.out
Program received signal SIGSEGV, Segmentation fault.
0x00000000004004cd in main () at null.c:7
7 *(int32_t *) 0 = 0;