David Howells f0d1b0b30d [PATCH] LOG2: Implement a general integer log2 facility in the kernel ... This facility provides three entry points: ilog2() Log base 2 of unsigned long ilog2_u32() Log base 2 of u32 ilog2_u64() Log base 2 of u64 These facilities can either be used inside functions on dynamic data: int do_something(long q) { ...; y = ilog2(x) ...; } Or can be used to statically initialise global variables with constant values: unsigned n = ilog2(27); When performing static initialisation, the compiler will report "error: initializer element is not constant" if asked to take a log of zero or of something not reducible to a constant. They treat negative numbers as unsigned. When not dealing with a constant, they fall back to using fls() which permits them to use arch-specific log calculation instructions - such as BSR on x86/x86_64 or SCAN on FRV - if available. [akpm@osdl.org: MMC fix] Signed-off-by: David Howells <dhowells@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: David Howells <dhowells@redhat.com> Cc: Wojtek Kaniewski <wojtekka@toxygen.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>		2006-12-08 08:28:51 -08:00
..
a.out.h
atomic.h	[PATCH] frv: NULL noise removal in frv xchg()	2006-06-23 07:42:55 -07:00
auxvec.h
ax88796.h
bitops.h	[PATCH] LOG2: Implement a general integer log2 facility in the kernel	2006-12-08 08:28:51 -08:00
bug.h	Don't include linux/config.h from anywhere else in include/	2006-04-26 12:56:16 +01:00
bugs.h
busctl-regs.h
byteorder.h
cache.h	Don't include linux/config.h from anywhere else in include/	2006-04-26 12:56:16 +01:00
cacheflush.h	[PATCH] FRV: Miscellaneous fixes	2006-02-14 16:09:35 -08:00
checksum.h	[NET]: FRV checksum annotations.	2006-12-02 21:23:03 -08:00
cpu-irqs.h	[PATCH] FRV: Use the generic IRQ stuff	2006-09-26 08:48:53 -07:00
cpumask.h
cputime.h
current.h
delay.h
device.h	Driver core: add dev_archdata to struct device	2006-12-01 14:52:01 -08:00
div64.h
dm9000.h
dma-mapping.h	[PATCH] Pass struct dev pointer to dma_cache_sync()	2006-12-07 08:39:41 -08:00
dma.h	IRQ: Maintain regs pointer globally rather than passing to IRQ handlers	2006-10-05 15:10:12 +01:00
elf.h	[PATCH] FDPIC: Add coredump capability for the ELF-FDPIC binfmt	2006-07-10 13:24:22 -07:00
emergency-restart.h
errno.h
fcntl.h
fpu.h	Don't include linux/config.h from anywhere else in include/	2006-04-26 12:56:16 +01:00
futex.h	[PATCH] lightweight robust futexes updates	2006-03-27 08:44:49 -08:00
gdb-stub.h	[PATCH] FRV: Introduce asm-offsets for FRV arch	2006-07-10 13:24:22 -07:00
gpio-regs.h
hardirq.h	[PATCH] FRV: Use the generic IRQ stuff	2006-09-26 08:48:53 -07:00
highmem.h	[PATCH] mm: pagefault_{disable,enable}()	2006-12-07 08:39:21 -08:00
hw_irq.h
ide.h	Don't include linux/config.h from anywhere else in include/	2006-04-26 12:56:16 +01:00
init.h
io.h	[PATCH] Consolidate check_signature	2006-10-11 11:14:23 -07:00
ioctl.h
ioctls.h
ipc.h
ipcbuf.h
irc-regs.h
irq_regs.h	IRQ: Maintain regs pointer globally rather than passing to IRQ handlers	2006-10-05 15:10:12 +01:00
irq.h	[PATCH] FRV: Use the generic IRQ stuff	2006-09-26 08:48:53 -07:00
Kbuild	Add empty Kbuild files for 'make headers_install' in remaining arches.	2006-06-18 12:58:53 +01:00
kmap_types.h
linkage.h
local.h
math-emu.h
mb86943a.h
mb93091-fpga-irqs.h	[PATCH] FRV: Use the generic IRQ stuff	2006-09-26 08:48:53 -07:00
mb93093-fpga-irqs.h	[PATCH] FRV: Use the generic IRQ stuff	2006-09-26 08:48:53 -07:00
mb93493-irqs.h	[PATCH] FRV: Use the generic IRQ stuff	2006-09-26 08:48:53 -07:00
mb93493-regs.h	[PATCH] FRV: Use the generic IRQ stuff	2006-09-26 08:48:53 -07:00
mb-regs.h	[PATCH] frv: basic __iomem annotations	2006-06-23 07:42:54 -07:00
mc146818rtc.h
mem-layout.h
mman.h	[PATCH] add asm-generic/mman.h	2006-02-15 15:32:22 -08:00
mmu_context.h	Don't include linux/config.h from anywhere else in include/	2006-04-26 12:56:16 +01:00
mmu.h
module.h
msgbuf.h
mutex.h
namei.h	fix file specification in comments	2006-10-03 23:01:26 +02:00
page.h	Don't include linux/config.h from anywhere else in include/	2006-04-26 12:56:16 +01:00
param.h	[PATCH] cleanup asm/setup.h userspace visibility	2006-12-07 08:39:46 -08:00
pci.h	Don't include linux/config.h from anywhere else in include/	2006-04-26 12:56:16 +01:00
percpu.h
pgalloc.h	Don't include linux/config.h from anywhere else in include/	2006-04-26 12:56:16 +01:00
pgtable.h	[PATCH] paravirt: remove set pte atomic	2006-10-01 00:39:34 -07:00
poll.h	[PATCH] POLLRDHUP/EPOLLRDHUP handling for half-closed devices notifications	2006-03-25 08:22:56 -08:00
posix_types.h
processor.h	[PATCH] Make cpu_relax() imply barrier() on all arches	2006-07-12 12:56:45 -07:00
ptrace.h	IRQ: Maintain regs pointer globally rather than passing to IRQ handlers	2006-10-05 15:10:12 +01:00
registers.h	[PATCH] FRV: Introduce asm-offsets for FRV arch	2006-07-10 13:24:22 -07:00
resource.h
scatterlist.h
sections.h
segment.h	Don't include linux/config.h from anywhere else in include/	2006-04-26 12:56:16 +01:00
semaphore.h
sembuf.h
serial-regs.h
serial.h	Don't include linux/config.h from anywhere else in include/	2006-04-26 12:56:16 +01:00
setup.h	[PATCH] cleanup asm/setup.h userspace visibility	2006-12-07 08:39:46 -08:00
shmbuf.h
shmparam.h
sigcontext.h
siginfo.h
signal.h	[PATCH] irq-flags: FRV: Use the new IRQF_ constants	2006-07-02 13:58:46 -07:00
smp.h	Don't include linux/config.h from anywhere else in include/	2006-04-26 12:56:16 +01:00
socket.h	[AF_UNIX]: Datagram getpeersec	2006-06-29 16:58:06 -07:00
sockios.h
spinlock.h
spr-regs.h	[PATCH] FRV: Use virtual interrupt disablement	2006-02-14 16:09:35 -08:00
stat.h
statfs.h
string.h
suspend.h
system.h	[PATCH] remove set_wmb - arch removal	2006-07-14 21:56:14 -07:00
termbits.h
termios.h
thread_info.h	[PATCH] FRV: Introduce asm-offsets for FRV arch	2006-07-10 13:24:22 -07:00
timer-regs.h
timex.h	[PATCH] ntp: cleanup defines and comments	2006-10-01 00:39:27 -07:00
tlb.h
tlbflush.h	Don't include linux/config.h from anywhere else in include/	2006-04-26 12:56:16 +01:00
topology.h
types.h	Don't include linux/config.h from anywhere else in include/	2006-04-26 12:56:16 +01:00
uaccess.h	[PATCH] frv: __user infrastructure	2006-06-23 07:42:54 -07:00
ucontext.h
unaligned.h	Don't include linux/config.h from anywhere else in include/	2006-04-26 12:56:16 +01:00
unistd.h	[PATCH] remove kernel syscalls	2006-12-07 08:39:37 -08:00
user.h
vga.h
virtconvert.h	Don't include linux/config.h from anywhere else in include/	2006-04-26 12:56:16 +01:00
xor.h