text: #include <stdint.h>
  #include <stddef.h>
  #include <stdarg.h>
  #include <lib/libc.h>
  #include <lib/blib.h>
  #include <lib/print.h>
  #include <lib/trace.h>
  #include <lib/real.h>
  #include <fs/file.h>
  #include <mm/pmm.h>
  
  #if uefi == 1
  EFI_SYSTEM_TABLE *gST;
  EFI_BOOT_SERVICES *gBS;
  EFI_RUNTIME_SERVICES *gRT;
  EFI_HANDLE efi_image_handle;
  EFI_MEMORY_DESCRIPTOR *efi_mmap = NULL;
  UINTN efi_mmap_size = 0, efi_desc_size = 0;
  UINT32 efi_desc_ver = 0;
  #endif
  
  bool parse_resolution(size_t *width, size_t *height, size_t *bpp, const char *buf) {
      size_t res[3] = {0};
  
      const char *first = buf;
      for (size_t i = 0; i < 3; i++) {
          const char *last;
          size_t x = strtoui(first, &last, 10);
          if (first == last)
              break;
          res[i] = x;
          if (*last == 0)
              break;
          first = last + 1;
      }
  
      if (res[0] == 0 || res[1] == 0)
          return false;
  
      if (res[2] == 0)
          res[2] = 32;
  
      *width = res[0], *height = res[1];
      if (bpp != NULL)
          *bpp = res[2];
  
      return true;
  }
  
  // This integer sqrt implementation has been adapted from:
  // https://stackoverflow.com/questions/1100090/looking-for-an-efficient-integer-square-root-algorithm-for-arm-thumb2
  uint64_t sqrt(uint64_t a_nInput) {
      uint64_t op  = a_nInput;
      uint64_t res = 0;
      uint64_t one = (uint64_t)1 << 62;
  
      // "one" starts at the highest power of four <= than the argument.
      while (one > op) {
          one >>= 2;
      }
  
      while (one != 0) {
          if (op >= res + one) {
              op = op - (res + one);
              res = res +  2 * one;
          }
          res >>= 1;
          one >>= 2;
      }
  
      return res;
  }
  
  size_t get_trailing_zeros(uint64_t val) {
      for (size_t i = 0; i < 64; i++) {
          if ((val & 1) != 0) {
              return i;
          }
          val >>= 1;
      }
      return 64;
  }
  
  // This table from https://web.mit.edu/freebsd/head/sys/libkern/crc32.c
  static const uint32_t crc32_table[] = {
  	0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
  	0xe963a535, 0x9e6495a3,	0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
  	0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
  	0xf3b97148, 0x84be41de,	0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
  	0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec,	0x14015c4f, 0x63066cd9,
  	0xfa0f3d63, 0x8d080df5,	0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
  	0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,	0x35b5a8fa, 0x42b2986c,
  	0xdbbbc9d6, 0xacbcf940,	0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
  	0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
  	0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
  	0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,	0x76dc4190, 0x01db7106,
  	0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
  	0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
  	0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
  	0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
  	0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
  	0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
  	0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
  	0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
  	0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
  	0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
  	0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
  	0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
  	0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
  	0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
  	0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
  	0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
  	0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
  	0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
  	0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
  	0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
  	0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
  	0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
  	0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
  	0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
  	0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
  	0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
  	0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
  	0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
  	0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
  	0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
  	0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
  	0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
  };
  
  uint32_t get_crc32(void *_stream, size_t len) {
      uint8_t *stream = _stream;
      uint32_t ret = 0xffffffff;
  
      for (size_t i = 0; i < len; i++) {
          ret = (ret >> 8) ^ crc32_table[(ret ^ stream[i]) & 0xff];
      }
  
      ret ^= 0xffffffff;
      return ret;
  }
  
  uint32_t oct2bin(uint8_t *str, uint32_t max) {
      uint32_t value = 0;
      while (max-- > 0) {
          value <<= 3;
          value += *str++ - '0';
      }
      return value;
  }
  
  uint32_t hex2bin(uint8_t *str, uint32_t size) {
      uint32_t value = 0;
      while (size-- > 0) {
          value <<= 4;
          if (*str >= '0' && *str <= '9')
              value += (uint32_t)((*str) - '0');
          else if (*str >= 'A' && *str <= 'F')
              value += (uint32_t)((*str) - 'A' + 10);
          else if (*str >= 'a' && *str <= 'f')
              value += (uint32_t)((*str) - 'a' + 10);
          str++;
      }
      return value;
  }
  
  #if uefi == 1
  
  bool efi_boot_services_exited = false;
  
  #define EFI_COPY_MAX_ENTRIES 512
  
  bool efi_exit_boot_services(void) {
      EFI_STATUS status;
  
      EFI_MEMORY_DESCRIPTOR tmp_mmap[1];
      efi_mmap_size = sizeof(tmp_mmap);
      UINTN mmap_key = 0;
  
      gBS->GetMemoryMap(&efi_mmap_size, tmp_mmap, &mmap_key, &efi_desc_size, &efi_desc_ver);
  
      efi_mmap_size += 4096;
  
      status = gBS->FreePool(efi_mmap);
      if (status)
          goto fail;
  
      status = gBS->AllocatePool(EfiLoaderData, efi_mmap_size, (void **)&efi_mmap);
      if (status)
          goto fail;
  
      status = gBS->GetMemoryMap(&efi_mmap_size, efi_mmap, &mmap_key, &efi_desc_size, &efi_desc_ver);
      if (status)
          goto fail;
  
      // Be gone, UEFI!
      status = gBS->ExitBootServices(efi_image_handle, mmap_key);
  
      asm volatile ("cli" ::: "memory");
  
      if (status)
          goto fail;
  
      pmm_reclaim_uefi_mem();
  
      // Go through new EFI memmap and free up bootloader entries
      size_t entry_count = efi_mmap_size / efi_desc_size;
  
      EFI_MEMORY_DESCRIPTOR *efi_copy = ext_mem_alloc(EFI_COPY_MAX_ENTRIES * efi_desc_size);
      size_t efi_copy_i = 0;
  
      for (size_t i = 0; i < entry_count; i++) {
          EFI_MEMORY_DESCRIPTOR *orig_entry = (void *)efi_mmap + i * efi_desc_size;
          EFI_MEMORY_DESCRIPTOR *new_entry = (void *)efi_copy + efi_copy_i * efi_desc_size;
  
          memcpy(new_entry, orig_entry, efi_desc_size);
  
          uint64_t base = orig_entry->PhysicalStart;
          uint64_t length = orig_entry->NumberOfPages * 4096;
          uint64_t top = base + length;
  
          // Find for a match in the untouched memory map
          for (size_t j = 0; j < untouched_memmap_entries; j++) {
              if (untouched_memmap[j].type != MEMMAP_USABLE)
                  continue;
  
              if (untouched_memmap[j].base >= base && untouched_memmap[j].base < top) {
                  if (untouched_memmap[j].base > base) {
                      new_entry->NumberOfPages = (untouched_memmap[j].base - base) / 4096;
  
                      efi_copy_i++;
                      if (efi_copy_i == EFI_COPY_MAX_ENTRIES) {
                          panic("efi: New memory map exhausted");
                      }
                      new_entry = (void *)efi_copy + efi_copy_i * efi_desc_size;
                      memcpy(new_entry, orig_entry, efi_desc_size);
  
                      new_entry->NumberOfPages -= (untouched_memmap[j].base - base) / 4096;
                      new_entry->PhysicalStart = untouched_memmap[j].base;
                      new_entry->VirtualStart = new_entry->PhysicalStart;
  
                      base = new_entry->PhysicalStart;
                      length = new_entry->NumberOfPages * 4096;
                      top = base + length;
                  }
  
                  if (length < untouched_memmap[j].length) {
                      panic("efi: Memory map corruption");
                  }
  
                  new_entry->Type = EfiConventionalMemory;
  
                  if (length == untouched_memmap[j].length) {
                      // It's a perfect match!
                      break;
                  }
  
                  new_entry->NumberOfPages = untouched_memmap[j].length / 4096;
  
                  efi_copy_i++;
                  if (efi_copy_i == EFI_COPY_MAX_ENTRIES) {
                      panic("efi: New memory map exhausted");
                  }
                  new_entry = (void *)efi_copy + efi_copy_i * efi_desc_size;
                  memcpy(new_entry, orig_entry, efi_desc_size);
  
                  new_entry->NumberOfPages = (length - untouched_memmap[j].length) / 4096;
                  new_entry->PhysicalStart = base + untouched_memmap[j].length;
                  new_entry->VirtualStart = new_entry->PhysicalStart;
  
                  break;
              }
          }
  
          efi_copy_i++;
          if (efi_copy_i == EFI_COPY_MAX_ENTRIES) {
              panic("efi: New memory map exhausted");
          }
      }
  
      efi_mmap = efi_copy;
      efi_mmap_size = efi_copy_i * efi_desc_size;
  
      efi_boot_services_exited = true;
  
      printv("efi: Exited boot services.\n");
  
      return true;
  
  fail:
      panic("efi: Failed to exit boot services");
  }
  
  #endif
  