Normal without an exception

void foo() {
    printf("hello world\n");
}

---
Load/Store access fault (exception 5, 7):

    int *ptr = (int*)0xdeadbeef;
    int b = *ptr;
    *ptr = 1;

---
Illegal instruction (exception 2)

    int *exit_code = (int*) 0x820000c;
    *exit_code = 0xdeadbeef;

---
Illegal instruction II (exception 2)

    asm("jr %0"::"r"(foo+2));
    // [this is an incorrect explained example in class, 
    //  where "foo" is in type "void *(void)",
    //  and "+2" advances the address by 2*sizeof(void*)]

    Q: difference between "jr" and "call"?

    asm("jr %0"::"r"(foo));
    printf("will not get here");

---
Illegal instruction (exception 2)

    asm("csrw mstatus, %0" ::"r"(0xdeadbeef));

---
explore MISP

  (gdb) display/t $mip
  (gdb) b syscall.c:46

---
linux: malloc too much memory


#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#define M256 1024*1024*256

int main() {
    unsigned long long counter = 0;
    while(1) {
        void *tmp = malloc(M256);
        counter += 256;
        memset(tmp, 0, M256);
        printf("allocated %.2f GB memory\n", counter/1024.0);
    }
}