arch/powerpc/lib/hweight_64.S

Source file repositories/reference/linux-study-clean/arch/powerpc/lib/hweight_64.S

File Facts

System: Linux kernel
Corpus path: arch/powerpc/lib/hweight_64.S
Extension: .S
Size: 1896 bytes
Lines: 105
Domain: Architecture Layer
Bucket: arch/powerpc
Inferred role: Architecture Layer: exported/initcall integration point
Status: integration implementation candidate

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.
Exports symbols or registers init work; inspect boot/module ordering and who consumes the exported contract.

Dependency Surface

linux/export.h
asm/processor.h
asm/ppc_asm.h
asm/feature-fixups.h

Detected Declarations

export __arch_hweight8
export __arch_hweight16
export __arch_hweight32
export __arch_hweight64

Annotated Snippet

#include <linux/export.h>
#include <asm/processor.h>
#include <asm/ppc_asm.h>
#include <asm/feature-fixups.h>

/* Note: This code relies on -mminimal-toc */

_GLOBAL(__arch_hweight8)
BEGIN_FTR_SECTION
	b CFUNC(__sw_hweight8)
	nop
	nop
FTR_SECTION_ELSE
	PPC_POPCNTB(R3,R3)
	clrldi	r3,r3,64-8
	blr
ALT_FTR_SECTION_END_IFCLR(CPU_FTR_POPCNTB)
EXPORT_SYMBOL(__arch_hweight8)

_GLOBAL(__arch_hweight16)
BEGIN_FTR_SECTION
	b CFUNC(__sw_hweight16)
	nop
	nop
	nop
	nop
FTR_SECTION_ELSE
  BEGIN_FTR_SECTION_NESTED(50)
	PPC_POPCNTB(R3,R3)
	srdi	r4,r3,8
	add	r3,r4,r3
	clrldi	r3,r3,64-8
	blr
  FTR_SECTION_ELSE_NESTED(50)
	clrlwi  r3,r3,16
	PPC_POPCNTW(R3,R3)
	clrldi	r3,r3,64-8
	blr
  ALT_FTR_SECTION_END_NESTED_IFCLR(CPU_FTR_POPCNTD, 50)
ALT_FTR_SECTION_END_IFCLR(CPU_FTR_POPCNTB)
EXPORT_SYMBOL(__arch_hweight16)

_GLOBAL(__arch_hweight32)
BEGIN_FTR_SECTION
	b CFUNC(__sw_hweight32)
	nop
	nop
	nop
	nop
	nop
	nop
FTR_SECTION_ELSE
  BEGIN_FTR_SECTION_NESTED(51)
	PPC_POPCNTB(R3,R3)
	srdi	r4,r3,16
	add	r3,r4,r3
	srdi	r4,r3,8
	add	r3,r4,r3
	clrldi	r3,r3,64-8
	blr
  FTR_SECTION_ELSE_NESTED(51)
	PPC_POPCNTW(R3,R3)
	clrldi	r3,r3,64-8
	blr
  ALT_FTR_SECTION_END_NESTED_IFCLR(CPU_FTR_POPCNTD, 51)
ALT_FTR_SECTION_END_IFCLR(CPU_FTR_POPCNTB)
EXPORT_SYMBOL(__arch_hweight32)

_GLOBAL(__arch_hweight64)
BEGIN_FTR_SECTION

Annotation

Immediate include surface: `linux/export.h`, `asm/processor.h`, `asm/ppc_asm.h`, `asm/feature-fixups.h`.
Detected declarations: `export __arch_hweight8`, `export __arch_hweight16`, `export __arch_hweight32`, `export __arch_hweight64`.
Atlas domain: Architecture Layer / arch/powerpc.
Implementation status: integration 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.