arch/arm/lib/ucmpdi2.S

File Facts

System

Linux kernel

Corpus path

arch/arm/lib/ucmpdi2.S

Extension

.S

Size

648 bytes

Lines

51

Domain

Architecture Layer

Bucket

arch/arm

Inferred role

Architecture Layer: arch/arm

Status

atlas-only

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

• CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

• linux/linkage.h
• asm/assembler.h

Detected Declarations

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

Annotated Snippet

#include <linux/linkage.h>
#include <asm/assembler.h>

#ifdef __ARMEB__
#define xh r0
#define xl r1
#define yh r2
#define yl r3
#else
#define xl r0
#define xh r1
#define yl r2
#define yh r3
#endif

ENTRY(__ucmpdi2)

	cmp	xh, yh
	cmpeq	xl, yl
	movlo	r0, #0
	moveq	r0, #1
	movhi	r0, #2
	ret	lr

ENDPROC(__ucmpdi2)

#ifdef CONFIG_AEABI

ENTRY(__aeabi_ulcmp)

	cmp	xh, yh
	cmpeq	xl, yl
	movlo	r0, #-1
	moveq	r0, #0
	movhi	r0, #1
	ret	lr

ENDPROC(__aeabi_ulcmp)

#endif

Annotation

• Immediate include surface: `linux/linkage.h`, `asm/assembler.h`.
• Atlas domain: Architecture Layer / arch/arm.
• Implementation status: atlas-only.

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.