tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Based on arch/x86/include/asm/arch_hweight.h
4 */
5
6#ifndef _ASM_RISCV_HWEIGHT_H
7#define _ASM_RISCV_HWEIGHT_H
8
9#include <asm/alternative-macros.h>
10#include <asm/hwcap.h>
11
12#if (BITS_PER_LONG == 64)
13#define CPOPW "cpopw "
14#elif (BITS_PER_LONG == 32)
15#define CPOPW "cpop "
16#else
17#error "Unexpected BITS_PER_LONG"
18#endif
19
20static __always_inline unsigned int __arch_hweight32(unsigned int w)
21{
22#if defined(CONFIG_RISCV_ISA_ZBB) && defined(CONFIG_TOOLCHAIN_HAS_ZBB)
23 asm goto(ALTERNATIVE("j %l[legacy]", "nop", 0,
24 RISCV_ISA_EXT_ZBB, 1)
25 : : : : legacy);
26
27 asm (".option push\n"
28 ".option arch,+zbb\n"
29 CPOPW "%0, %1\n"
30 ".option pop\n"
31 : "=r" (w) : "r" (w) :);
32
33 return w;
34
35legacy:
36#endif
37 return __sw_hweight32(w);
38}
39
40static inline unsigned int __arch_hweight16(unsigned int w)
41{
42 return __arch_hweight32(w & 0xffff);
43}
44
45static inline unsigned int __arch_hweight8(unsigned int w)
46{
47 return __arch_hweight32(w & 0xff);
48}
49
50#if BITS_PER_LONG == 64
51static __always_inline unsigned long __arch_hweight64(__u64 w)
52{
53#if defined(CONFIG_RISCV_ISA_ZBB) && defined(CONFIG_TOOLCHAIN_HAS_ZBB)
54 asm goto(ALTERNATIVE("j %l[legacy]", "nop", 0,
55 RISCV_ISA_EXT_ZBB, 1)
56 : : : : legacy);
57
58 asm (".option push\n"
59 ".option arch,+zbb\n"
60 "cpop %0, %1\n"
61 ".option pop\n"
62 : "=r" (w) : "r" (w) :);
63
64 return w;
65
66legacy:
67#endif
68 return __sw_hweight64(w);
69}
70#else /* BITS_PER_LONG == 64 */
71static inline unsigned long __arch_hweight64(__u64 w)
72{
73 return __arch_hweight32((u32)w) +
74 __arch_hweight32((u32)(w >> 32));
75}
76#endif /* !(BITS_PER_LONG == 64) */
77
78#endif /* _ASM_RISCV_HWEIGHT_H */