Eric Lee / smarc-ti-linux-kernel

Download as
Browse Code ยป

Commit 3b9ed1a5d2d121f32d2cb4f2b05f1fc57c99c946

Authored by Akinobu Mita
Committed by Linus Torvalds
1 parent 09020adb61

[PATCH] bitops: generic hweight{64,32,16,8}() 

This patch introduces the C-language equivalents of the functions below:

unsigned int hweight32(unsigned int w);
unsigned int hweight16(unsigned int w);
unsigned int hweight8(unsigned int w);
unsigned long hweight64(__u64 w);

In include/asm-generic/bitops/hweight.h

This code largely copied from: include/linux/bitops.h

Signed-off-by: Akinobu Mita <mita@miraclelinux.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Showing 3 changed files with 64 additions and 0 deletions Inline Diff

include/asm-generic/bitops/hweight.h
Diff comments   View file @ 3b9ed1a
File was created 1 #ifndef _ASM_GENERIC_BITOPS_HWEIGHT_H_
2 #define _ASM_GENERIC_BITOPS_HWEIGHT_H_
3
4 extern unsigned int hweight32(unsigned int w);
5 extern unsigned int hweight16(unsigned int w);
6 extern unsigned int hweight8(unsigned int w);
7 extern unsigned long hweight64(__u64 w);
8
9 #endif /* _ASM_GENERIC_BITOPS_HWEIGHT_H_ */
10
1 # 1 #
2 # Makefile for some libs needed in the kernel. 2 # Makefile for some libs needed in the kernel.
3 # 3 #
4 4
5 lib-y := errno.o ctype.o string.o vsprintf.o cmdline.o \ 5 lib-y := errno.o ctype.o string.o vsprintf.o cmdline.o \
6 bust_spinlocks.o rbtree.o radix-tree.o dump_stack.o \ 6 bust_spinlocks.o rbtree.o radix-tree.o dump_stack.o \
7 idr.o div64.o int_sqrt.o bitmap.o extable.o prio_tree.o \ 7 idr.o div64.o int_sqrt.o bitmap.o extable.o prio_tree.o \
8 sha1.o 8 sha1.o
9 9
10 lib-$(CONFIG_SMP) += cpumask.o 10 lib-$(CONFIG_SMP) += cpumask.o
11 11
12 lib-y += kobject.o kref.o kobject_uevent.o klist.o 12 lib-y += kobject.o kref.o kobject_uevent.o klist.o
13 13
14 obj-y += sort.o parser.o halfmd4.o iomap_copy.o 14 obj-y += sort.o parser.o halfmd4.o iomap_copy.o
15 15
16 ifeq ($(CONFIG_DEBUG_KOBJECT),y) 16 ifeq ($(CONFIG_DEBUG_KOBJECT),y)
17 CFLAGS_kobject.o += -DDEBUG 17 CFLAGS_kobject.o += -DDEBUG
18 CFLAGS_kobject_uevent.o += -DDEBUG 18 CFLAGS_kobject_uevent.o += -DDEBUG
19 endif 19 endif
20 20
21 obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o 21 obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
22 lib-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o 22 lib-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
23 lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o 23 lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o
24 lib-$(CONFIG_SEMAPHORE_SLEEPERS) += semaphore-sleepers.o 24 lib-$(CONFIG_SEMAPHORE_SLEEPERS) += semaphore-sleepers.o
25 lib-$(CONFIG_GENERIC_FIND_NEXT_BIT) += find_next_bit.o 25 lib-$(CONFIG_GENERIC_FIND_NEXT_BIT) += find_next_bit.o
26 lib-$(CONFIG_GENERIC_HWEIGHT) += hweight.o
26 obj-$(CONFIG_LOCK_KERNEL) += kernel_lock.o 27 obj-$(CONFIG_LOCK_KERNEL) += kernel_lock.o
27 obj-$(CONFIG_DEBUG_PREEMPT) += smp_processor_id.o 28 obj-$(CONFIG_DEBUG_PREEMPT) += smp_processor_id.o
28 29
29 ifneq ($(CONFIG_HAVE_DEC_LOCK),y) 30 ifneq ($(CONFIG_HAVE_DEC_LOCK),y)
30 lib-y += dec_and_lock.o 31 lib-y += dec_and_lock.o
31 endif 32 endif
32 33
33 obj-$(CONFIG_CRC_CCITT) += crc-ccitt.o 34 obj-$(CONFIG_CRC_CCITT) += crc-ccitt.o
34 obj-$(CONFIG_CRC16) += crc16.o 35 obj-$(CONFIG_CRC16) += crc16.o
35 obj-$(CONFIG_CRC32) += crc32.o 36 obj-$(CONFIG_CRC32) += crc32.o
36 obj-$(CONFIG_LIBCRC32C) += libcrc32c.o 37 obj-$(CONFIG_LIBCRC32C) += libcrc32c.o
37 obj-$(CONFIG_GENERIC_IOMAP) += iomap.o 38 obj-$(CONFIG_GENERIC_IOMAP) += iomap.o
38 obj-$(CONFIG_GENERIC_ALLOCATOR) += genalloc.o 39 obj-$(CONFIG_GENERIC_ALLOCATOR) += genalloc.o
39 40
40 obj-$(CONFIG_ZLIB_INFLATE) += zlib_inflate/ 41 obj-$(CONFIG_ZLIB_INFLATE) += zlib_inflate/
41 obj-$(CONFIG_ZLIB_DEFLATE) += zlib_deflate/ 42 obj-$(CONFIG_ZLIB_DEFLATE) += zlib_deflate/
42 obj-$(CONFIG_REED_SOLOMON) += reed_solomon/ 43 obj-$(CONFIG_REED_SOLOMON) += reed_solomon/
43 44
44 obj-$(CONFIG_TEXTSEARCH) += textsearch.o 45 obj-$(CONFIG_TEXTSEARCH) += textsearch.o
45 obj-$(CONFIG_TEXTSEARCH_KMP) += ts_kmp.o 46 obj-$(CONFIG_TEXTSEARCH_KMP) += ts_kmp.o
46 obj-$(CONFIG_TEXTSEARCH_BM) += ts_bm.o 47 obj-$(CONFIG_TEXTSEARCH_BM) += ts_bm.o
47 obj-$(CONFIG_TEXTSEARCH_FSM) += ts_fsm.o 48 obj-$(CONFIG_TEXTSEARCH_FSM) += ts_fsm.o
48 49
49 obj-$(CONFIG_SWIOTLB) += swiotlb.o 50 obj-$(CONFIG_SWIOTLB) += swiotlb.o
50 51
51 hostprogs-y := gen_crc32table 52 hostprogs-y := gen_crc32table
52 clean-files := crc32table.h 53 clean-files := crc32table.h
53 54
54 $(obj)/crc32.o: $(obj)/crc32table.h 55 $(obj)/crc32.o: $(obj)/crc32table.h
55 56
56 quiet_cmd_crc32 = GEN $@ 57 quiet_cmd_crc32 = GEN $@
57 cmd_crc32 = $< > $@ 58 cmd_crc32 = $< > $@
58 59
59 $(obj)/crc32table.h: $(obj)/gen_crc32table 60 $(obj)/crc32table.h: $(obj)/gen_crc32table
60 $(call cmd,crc32) 61 $(call cmd,crc32)
61 62
File was created 1 #include <linux/module.h>
2 #include <asm/types.h>
3
4 /**
5 * hweightN - returns the hamming weight of a N-bit word
6 * @x: the word to weigh
7 *
8 * The Hamming Weight of a number is the total number of bits set in it.
9 */
10
11 unsigned int hweight32(unsigned int w)
12 {
13 unsigned int res = (w & 0x55555555) + ((w >> 1) & 0x55555555);
14 res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
15 res = (res & 0x0F0F0F0F) + ((res >> 4) & 0x0F0F0F0F);
16 res = (res & 0x00FF00FF) + ((res >> 8) & 0x00FF00FF);
17 return (res & 0x0000FFFF) + ((res >> 16) & 0x0000FFFF);
18 }
19 EXPORT_SYMBOL(hweight32);
20
21 unsigned int hweight16(unsigned int w)
22 {
23 unsigned int res = (w & 0x5555) + ((w >> 1) & 0x5555);
24 res = (res & 0x3333) + ((res >> 2) & 0x3333);
25 res = (res & 0x0F0F) + ((res >> 4) & 0x0F0F);
26 return (res & 0x00FF) + ((res >> 8) & 0x00FF);
27 }
28 EXPORT_SYMBOL(hweight16);
29
30 unsigned int hweight8(unsigned int w)
31 {
32 unsigned int res = (w & 0x55) + ((w >> 1) & 0x55);
33 res = (res & 0x33) + ((res >> 2) & 0x33);
34 return (res & 0x0F) + ((res >> 4) & 0x0F);
35 }
36 EXPORT_SYMBOL(hweight8);
37
38 unsigned long hweight64(__u64 w)
39 {
40 #if BITS_PER_LONG == 32
41 return hweight32((unsigned int)(w >> 32)) + hweight32((unsigned int)w);
42 #elif BITS_PER_LONG == 64
43 u64 res;
44 res = (w & 0x5555555555555555ul) + ((w >> 1) & 0x5555555555555555ul);
45 res = (res & 0x3333333333333333ul) + ((res >> 2) & 0x3333333333333333ul);
46 res = (res & 0x0F0F0F0F0F0F0F0Ful) + ((res >> 4) & 0x0F0F0F0F0F0F0F0Ful);
47 res = (res & 0x00FF00FF00FF00FFul) + ((res >> 8) & 0x00FF00FF00FF00FFul);
48 res = (res & 0x0000FFFF0000FFFFul) + ((res >> 16) & 0x0000FFFF0000FFFFul);
49 return (res & 0x00000000FFFFFFFFul) + ((res >> 32) & 0x00000000FFFFFFFFul);
50 #else
51 #error BITS_PER_LONG not defined
52 #endif
53 }
54 EXPORT_SYMBOL(hweight64);
55