| //===----------------------------------------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| /// |
| /// \file |
| /// Linux implementation of major. |
| /// |
| //===----------------------------------------------------------------------===// |
| |
| #include "src/sys/sysmacros/major.h" |
| #include "hdr/types/dev_t.h" |
| #include "src/__support/common.h" |
| #include "src/__support/macros/config.h" |
| |
| namespace LIBC_NAMESPACE_DECL { |
| |
| static_assert(sizeof(dev_t) == 8, "dev_t must be 64-bit"); |
| |
| // dev_t is encoded as MMMM Mmmm mmmM MMmm, where each M represents 4 bytes |
| // of the major number and m represents 4 bytes of the minor number. We don't |
| // support older systems with smaller dev_t types. |
| |
| LLVM_LIBC_FUNCTION(unsigned int, major, (dev_t dev)) { |
| return static_cast<unsigned int>(((dev >> 8) & 0x00000fff) | |
| ((dev >> 32) & 0xfffff000)); |
| } |
| |
| } // namespace LIBC_NAMESPACE_DECL |
