#include "common.h"
#include "print.h"

#include "../include/limine.h"

// credit to dreamportdev's OSDev-Notes and the OSDev Wiki for table layouts

#include "acpi.h"
#define RSDT_SIGNATURE "RSDT"
#define XSDT_SIGNATURE "XSDT"

bool rsdp_validate(const u8* data) {
  if(memcmp(data, (const u8*)RSDP_SIGNATURE, 8) != 0) {
    /* to debug in memcmp is broken somehow */
    if(data[0] == 'R' && data[1] == 'S' && data[2] == 'D' && data[3] == 'T' && data[4] == ' ') {
      printn((const char*)data, 8);
    }
    return false;
  }

  struct acpi_rsdp_header* head = (struct acpi_rsdp_header*)data;
  size_t len = sizeof(struct acpi_rsdp_header);
  len -= (head->revision == 2) * sizeof(u32) + sizeof(u64) + sizeof(u8) + sizeof(u8[3]);
  u32 sum_to_zero = 0;
  for(size_t i = 0; i < len; i++) {
    sum_to_zero += data[i];
  }

  return (sum_to_zero & 0xFF) == 0;
}

static bool use_xsdt = false;

static struct acpi_rsdt* rsdt;
static struct acpi_xsdt* xsdt;

struct acpi_sdt_header* acpi_get_header(size_t n) {
  return (struct acpi_sdt_header*) (use_xsdt? xsdt->addrs[n] : (u64)rsdt->addrs[n]);
}

struct acpi_rsdp_header* rsdp;