#include <stdint.h>
#include <stdlib.h>

#include "fat12.h"

#define kPolmonAddress ((void*)0x0600)
#define kFatAddress ((void*)0x1000)
#define kRootDirAddress ((void*)0x1200)

static int putchar(int c) {
    register uint8_t khar asm("al") = c;
    register uint8_t func asm("ah") = 0x0e;
    register uint8_t page asm("bh") = 0;

    asm volatile("int $0x10" ::"r"(khar), "r"(func), "r"(page) : "bp");

    return c;
}

static int puts(const char* msg) {
    while (*msg) {
        putchar(*msg++);
    }
    return 0;
}

__attribute__((noreturn)) static void die(const char* msg) {
    puts(msg);
    while (1) {
    }
    __builtin_unreachable();
}

__attribute__((noreturn)) static void jump(void* addr) {
    asm volatile("ljmp $0,%0" ::"i"(addr));
    __builtin_unreachable();
}

__attribute__((noreturn)) static void loadpolmon() {
    if (fat12_init(kFatAddress, kRootDirAddress)) {
        die("fi");
    }

    while (fat12_readfile("POLIO   COM", kPolmonAddress)) {
        asm volatile("mov $00, %%ah      \n\t"
                     "int $0x16          \n\t" ::
                             : "ax");
    }

    jump(kPolmonAddress);
}

int main() { loadpolmon(); }