#include "../../../vm/vm.h"
#include <stdio.h>
#include <string.h>

#define CODE_SIZE 8192
#define MEMORY_SIZE 65536
u8 lmem[MEMORY_SIZE] = {0};
u32 lcode[CODE_SIZE] = {0};

bool init_vm() {
  mem = lmem;
  memset(mem, 0, MEMORY_SIZE*sizeof(u8));
  code = lcode;
  lc = 0;
  mp = 0;
  cp = 0;
  pc = 0;
  interrupt = 0;
  status = 0;
  return true;
}

u32 syscall(u32 id, u32 size, u32 mem_ptr) {
  USED(size);
  switch(id) {
  case SYSCALL_DBG_PRINT: {
    u32 val = READ_U32(mem_ptr);
    printf("%d\n", val);
    return 0;
  }
  }

  return 1; // generic error
}

void test_add_two_num() {
  i32 main_local_count = 4; 
  mp += (4 * main_local_count);
  code[cp++] = ENCODE_B(OP_LOAD_IMM, 0, 1);
  code[cp++] = ENCODE_B(OP_PUSH, 0, 0);
  code[cp++] = ENCODE_B(OP_LOAD_IMM, 1, 1);
  code[cp++] = ENCODE_B(OP_PUSH, 1, 0);
  i32 add = cp + 4;
  code[cp++] = ENCODE_B(OP_LOAD_IMM, 2, add);
  code[cp++] = ENCODE_A(OP_CALL, 2, 3, 3);
  code[cp++] = ENCODE_A(OP_SYSCALL, SYSCALL_DBG_PRINT, 1, 3);
  code[cp++] = ENCODE_A(OP_HALT, 0, 0, 0);

  /* add */
  code[cp++] = ENCODE_A(OP_ADD_INT, 2, 1, 0);
  code[cp++] = ENCODE_B(OP_RETURN, 2, 0);
}

void test_fibonacci() {
  i32 fib = 6;
  i32 base_case = 20;
  /* function main() */
  i32 main_local_count = 3; 
  mp += (4 * main_local_count);
  /* fib(35) */
  code[cp++] = ENCODE_B(OP_LOAD_IMM, 0, 35);
  code[cp++] = ENCODE_B(OP_PUSH, 0, 0);
  code[cp++] = ENCODE_B(OP_LOAD_IMM, 1, fib);
  code[cp++] = ENCODE_A(OP_CALL, 1, 9, 2);
  /* print */
  code[cp++] = ENCODE_A(OP_SYSCALL, SYSCALL_DBG_PRINT, 1, 2);
  code[cp++] = ENCODE_A(OP_HALT, 0, 0, 0);
  /* function fib (int n) int */
  //code[cp++] = ENCODE_A(OP_SYSCALL, SYSCALL_DBG_PRINT, 1, 0);
  code[cp++] = ENCODE_B(OP_LOAD_IMM, 8, fib);
  code[cp++] = ENCODE_B(OP_LOAD_IMM, 1, 2);
  code[cp++] = ENCODE_B(OP_LOAD_IMM, 2, base_case);
  code[cp++] = ENCODE_A(OP_JLT_INT, 2, 0, 1);
  code[cp++] = ENCODE_B(OP_LOAD_IMM, 3, 2);
  code[cp++] = ENCODE_A(OP_SUB_INT, 4, 0, 3);
  code[cp++] = ENCODE_B(OP_PUSH, 4, 0);
  code[cp++] = ENCODE_A(OP_CALL, 8, 9, 5);
  code[cp++] = ENCODE_B(OP_LOAD_IMM, 3, 1);
  code[cp++] = ENCODE_A(OP_SUB_INT, 4, 0, 3);
  code[cp++] = ENCODE_B(OP_PUSH, 4, 0);
  code[cp++] = ENCODE_A(OP_CALL, 8, 9, 6);
  code[cp++] = ENCODE_A(OP_ADD_INT, 7, 6, 5);
  code[cp++] = ENCODE_B(OP_RETURN, 7, 0);
  code[cp++] = ENCODE_B(OP_RETURN, 0, 0);
}

i32 main() {
  init_vm();

  /* test_add_two_num(); */
  test_fibonacci();

  while(step_vm()) {
    // do stuff
  }
  return 0;
}