arch/s390/include/asm/arch_hweight.h

Source file repositories/reference/linux-study-clean/arch/s390/include/asm/arch_hweight.h

File Facts

System
Linux kernel
Corpus path
arch/s390/include/asm/arch_hweight.h
Extension
.h
Size
1695 bytes
Lines
78
Domain
Architecture Layer
Bucket
arch/s390
Inferred role
Architecture Layer: implementation source
Status
source 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.

Dependency Surface

Detected Declarations

Annotated Snippet

#ifndef _ASM_S390_ARCH_HWEIGHT_H
#define _ASM_S390_ARCH_HWEIGHT_H

#include <linux/types.h>
#include <asm/march.h>

static __always_inline unsigned long popcnt_z196(unsigned long w)
{
	unsigned long cnt;

	asm volatile(".insn	rrf,0xb9e10000,%[cnt],%[w],0,0"
		     : [cnt] "=d" (cnt)
		     : [w] "d" (w)
		     : "cc");
	return cnt;
}

static __always_inline unsigned long popcnt_z15(unsigned long w)
{
	unsigned long cnt;

	asm volatile(".insn	rrf,0xb9e10000,%[cnt],%[w],8,0"
		     : [cnt] "=d" (cnt)
		     : [w] "d" (w)
		     : "cc");
	return cnt;
}

static __always_inline unsigned long __arch_hweight64(__u64 w)
{
	if (__is_defined(MARCH_HAS_Z15_FEATURES))
		return popcnt_z15(w);
	if (__is_defined(MARCH_HAS_Z196_FEATURES)) {
		w = popcnt_z196(w);
		w += w >> 32;
		w += w >> 16;
		w += w >> 8;
		return w & 0xff;
	}
	return __sw_hweight64(w);
}

static __always_inline unsigned int __arch_hweight32(unsigned int w)
{
	if (__is_defined(MARCH_HAS_Z15_FEATURES))
		return popcnt_z15(w);
	if (__is_defined(MARCH_HAS_Z196_FEATURES)) {
		w = popcnt_z196(w);
		w += w >> 16;
		w += w >> 8;
		return w & 0xff;
	}
	return __sw_hweight32(w);
}

static __always_inline unsigned int __arch_hweight16(unsigned int w)
{
	if (__is_defined(MARCH_HAS_Z15_FEATURES))
		return popcnt_z15((unsigned short)w);
	if (__is_defined(MARCH_HAS_Z196_FEATURES)) {
		w = popcnt_z196(w);
		w += w >> 8;
		return w & 0xff;
	}
	return __sw_hweight16(w);
}

static __always_inline unsigned int __arch_hweight8(unsigned int w)
{
	if (__is_defined(MARCH_HAS_Z196_FEATURES))
		return popcnt_z196((unsigned char)w);
	return __sw_hweight8(w);
}

#endif /* _ASM_S390_ARCH_HWEIGHT_H */

Annotation

Implementation Notes