include/linux/bitrev.h

File Facts

System

Linux kernel

Corpus path

include/linux/bitrev.h

Extension

.h

Size

2439 bytes

Lines

94

Domain

Core OS

Bucket

Core Kernel Interface

Inferred role

Core OS: implementation source

Status

source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

• Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

• linux/types.h
• asm/bitrev.h
• asm-generic/bitops/__bitrev.h

Detected Declarations

• No top-level syscall, struct, function, initcall, or export declaration detected by the generator.

Annotated Snippet

#ifndef _LINUX_BITREV_H
#define _LINUX_BITREV_H

#include <linux/types.h>

#ifdef CONFIG_HAVE_ARCH_BITREVERSE
#include <asm/bitrev.h>

#define __bitrev32 __arch_bitrev32
#define __bitrev16 __arch_bitrev16
#define __bitrev8 __arch_bitrev8

#else
#include <asm-generic/bitops/__bitrev.h>
#define __bitrev32 generic___bitrev32
#define __bitrev16 generic___bitrev16
#define __bitrev8 generic___bitrev8
#endif /* CONFIG_HAVE_ARCH_BITREVERSE */

#define __bitrev8x4(x)	(__bitrev32(swab32(x)))

#define __constant_bitrev32(x)	\
({					\
	u32 ___x = x;			\
	___x = (___x >> 16) | (___x << 16);	\
	___x = ((___x & (u32)0xFF00FF00UL) >> 8) | ((___x & (u32)0x00FF00FFUL) << 8);	\
	___x = ((___x & (u32)0xF0F0F0F0UL) >> 4) | ((___x & (u32)0x0F0F0F0FUL) << 4);	\
	___x = ((___x & (u32)0xCCCCCCCCUL) >> 2) | ((___x & (u32)0x33333333UL) << 2);	\
	___x = ((___x & (u32)0xAAAAAAAAUL) >> 1) | ((___x & (u32)0x55555555UL) << 1);	\
	___x;								\
})

#define __constant_bitrev16(x)	\
({					\
	u16 ___x = x;			\
	___x = (___x >> 8) | (___x << 8);	\
	___x = ((___x & (u16)0xF0F0U) >> 4) | ((___x & (u16)0x0F0FU) << 4);	\
	___x = ((___x & (u16)0xCCCCU) >> 2) | ((___x & (u16)0x3333U) << 2);	\
	___x = ((___x & (u16)0xAAAAU) >> 1) | ((___x & (u16)0x5555U) << 1);	\
	___x;								\
})

#define __constant_bitrev8x4(x) \
({			\
	u32 ___x = x;	\
	___x = ((___x & (u32)0xF0F0F0F0UL) >> 4) | ((___x & (u32)0x0F0F0F0FUL) << 4);	\
	___x = ((___x & (u32)0xCCCCCCCCUL) >> 2) | ((___x & (u32)0x33333333UL) << 2);	\
	___x = ((___x & (u32)0xAAAAAAAAUL) >> 1) | ((___x & (u32)0x55555555UL) << 1);	\
	___x;								\
})

#define __constant_bitrev8(x)	\
({					\
	u8 ___x = x;			\
	___x = (___x >> 4) | (___x << 4);	\
	___x = ((___x & (u8)0xCCU) >> 2) | ((___x & (u8)0x33U) << 2);	\
	___x = ((___x & (u8)0xAAU) >> 1) | ((___x & (u8)0x55U) << 1);	\
	___x;								\
})

#define bitrev32(x) \
({			\
	u32 __x = x;	\
	__builtin_constant_p(__x) ?	\
	__constant_bitrev32(__x) :			\
	__bitrev32(__x);				\
})

#define bitrev16(x) \
({			\
	u16 __x = x;	\
	__builtin_constant_p(__x) ?	\
	__constant_bitrev16(__x) :			\
	__bitrev16(__x);				\
 })

#define bitrev8x4(x) \
({			\
	u32 __x = x;	\
	__builtin_constant_p(__x) ?	\
	__constant_bitrev8x4(__x) :			\
	__bitrev8x4(__x);				\
 })

#define bitrev8(x) \
({			\
	u8 __x = x;	\
	__builtin_constant_p(__x) ?	\
	__constant_bitrev8(__x) :			\
	__bitrev8(__x)	;			\

Annotation

• Immediate include surface: `linux/types.h`, `asm/bitrev.h`, `asm-generic/bitops/__bitrev.h`.
• Atlas domain: Core OS / Core Kernel Interface.
• Implementation status: source implementation candidate.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.