redonkable
/
remarkable-linux
1
0
Fork 0
Code Releases Activity
remarkable-linux/include/asm-generic
History
Denys Vlasenko 133fd9f5cd vsprintf: further optimize decimal conversion 
Previous code was using optimizations which were developed to work well
even on narrow-word CPUs (by today's standards).  But Linux runs only on
32-bit and wider CPUs.  We can use that.

First: using 32x32->64 multiply and trivial 32-bit shift, we can correctly
divide by 10 much larger numbers, and thus we can print groups of 9 digits
instead of groups of 5 digits.

Next: there are two algorithms to print larger numbers.  One is generic:
divide by 1000000000 and repeatedly print groups of (up to) 9 digits.
It's conceptually simple, but requires an (unsigned long long) /
1000000000 division.

Second algorithm splits 64-bit unsigned long long into 16-bit chunks,
manipulates them cleverly and generates groups of 4 decimal digits.  It so
happens that it does NOT require long long division.

If long is > 32 bits, division of 64-bit values is relatively easy, and we
will use the first algorithm.  If long long is > 64 bits (strange
architecture with VERY large long long), second algorithm can't be used,
and we again use the first one.

Else (if long is 32 bits and long long is 64 bits) we use second one.

And third: there is a simple optimization which takes fast path not only
for zero as was done before, but for all one-digit numbers.

In all tested cases new code is faster than old one, in many cases by 30%,
in few cases by more than 50% (for example, on x86-32, conversion of
12345678).  Code growth is ~0 in 32-bit case and ~130 bytes in 64-bit
case.

This patch is based upon an original from Michal Nazarewicz.

[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Douglas W Jones <jones@cs.uiowa.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 		2012-05-31 17:49:27 -07:00
..
bitops Add #includes needed to permit the removal of asm/system.h 2012-03-28 18:30:03 +01:00
4level-fixup.h mm: Pass virtual address to [__]p{te,ud,md}_free_tlb() 2009-07-27 12:10:38 -07:00
Kbuild include: replace unifdef-y with header-y 2010-08-14 22:26:51 +02:00
Kbuild.asm include: replace unifdef-y with header-y 2010-08-14 22:26:51 +02:00
atomic-long.h asm-generic: merge branch 'master' of torvalds/linux-2.6 2009-06-12 11:32:58 +02:00
atomic.h Remove all #inclusions of asm/system.h 2012-03-28 18:30:03 +01:00
atomic64.h lib: Provide generic atomic64_t implementation 2009-06-15 13:27:38 +10:00
audit_change_attr.h audit: support the "standard" <asm-generic/unistd.h> 2011-05-04 14:41:28 -04:00
audit_dir_write.h audit: support the "standard" <asm-generic/unistd.h> 2011-05-04 14:41:28 -04:00
audit_read.h audit: support the "standard" <asm-generic/unistd.h> 2011-05-04 14:41:28 -04:00
audit_signal.h [PATCH] add SIGNAL syscall class (v3) 2007-05-11 05:38:25 -04:00
audit_write.h audit: support the "standard" <asm-generic/unistd.h> 2011-05-04 14:41:28 -04:00
auxvec.h asm-generic: add generic ABI headers 2009-06-11 21:02:15 +02:00
barrier.h Create asm-generic/barrier.h 2012-03-28 18:30:03 +01:00
bitops.h bitops: remove minix bitops from asm/bitops.h 2011-03-23 19:46:22 -07:00
bitsperlong.h vsprintf: further optimize decimal conversion 2012-05-31 17:49:27 -07:00
bug.h consolidate WARN_...ONCE() static variables 2012-03-23 16:58:31 -07:00
bugs.h asm-generic: add generic versions of common headers 2009-06-11 21:02:37 +02:00
cache.h asm-generic: add generic NOMMU versions of some headers 2009-06-11 21:02:50 +02:00
cacheflush.h asm-generic/cacheflush.h: flush icache when copying to user pages 2011-05-25 08:39:37 -07:00
checksum.h Add extra arch overrides to asm-generic/checksum.h 2011-11-01 07:34:21 -07:00
cmpxchg-local.h Fix IRQ flag handling naming 2010-10-07 14:08:55 +01:00
cmpxchg.h asm-generic: add linux/types.h to cmpxchg.h 2012-04-02 14:41:27 -07:00
cputime.h Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-01-06 08:44:54 -08:00
current.h asm-generic: add generic versions of common headers 2009-06-11 21:02:37 +02:00
delay.h asm-generic: delay.h fix udelay and ndelay for 8 bit args 2011-07-22 18:45:33 +02:00
device.h Driver Core: Add platform device arch data V3 2009-07-22 00:28:38 +02:00
div64.h rename div64_64 to div64_u64 2008-05-01 08:03:58 -07:00
dma-coherent.h common: add dma_mmap_from_coherent() function 2012-05-21 15:06:09 +02:00
dma-contiguous.h drivers: add Contiguous Memory Allocator 2012-05-21 15:09:37 +02:00
dma-mapping-broken.h dma-mapping: remove dma_is_consistent API 2010-08-11 08:59:21 -07:00
dma-mapping-common.h BUG: headers with BUG/BUG_ON etc. need linux/bug.h 2012-03-04 17:54:34 -05:00
dma.h asm-generic: add legacy I/O header files 2009-06-11 21:02:42 +02:00
emergency-restart.h
…
errno-base.h
…
errno.h mm: make __get_user_pages return -EHWPOISON for HWPOISON page optionally 2011-03-17 13:08:27 -03:00
exec.h Split arch_align_stack() out from asm-generic/system.h 2012-03-28 18:30:03 +01:00
fb.h asm-generic: add generic versions of common headers 2009-06-11 21:02:37 +02:00
fcntl.h locks: move F_INPROGRESS from fl_type to fl_flags field 2011-08-19 13:25:34 -04:00
ftrace.h asm-generic headers: add ftrace.h 2011-03-17 09:19:04 +08:00
futex.h futex: Sanitize futex ops argument types 2011-03-11 12:23:31 +01:00
getorder.h bitops: Add missing parentheses to new get_order macro 2012-02-24 10:39:27 -08:00
gpio.h gpiolib: Remove 'const' from data argument of gpiochip_find() 2012-05-18 23:01:05 -06:00
hardirq.h Fix IRQ flag handling naming 2010-10-07 14:08:55 +01:00
hw_irq.h asm-generic: add legacy I/O header files 2009-06-11 21:02:42 +02:00
ide_iops.h
…
int-l64.h asm-generic: introduce asm/bitsperlong.h 2009-06-11 21:02:14 +02:00
int-ll64.h asm-generic: introduce asm/bitsperlong.h 2009-06-11 21:02:14 +02:00
io-64-nonatomic-hi-lo.h asm-generic: architecture independent readq/writeq for 32bit environment 2012-02-21 16:47:28 -08:00
io-64-nonatomic-lo-hi.h asm-generic: architecture independent readq/writeq for 32bit environment 2012-02-21 16:47:28 -08:00
io.h lib: use generic pci_iomap on all architectures 2012-01-10 18:04:27 -08:00
ioctl.h Make ioctl.h compatible with userland 2008-08-12 16:07:31 -07:00
ioctls.h tty: add TIOCVHANGUP to allow clean tty shutdown of all ttys 2011-02-17 14:16:30 -08:00
iomap.h [PARISC] fix compile break caused by iomap: make IOPORT/PCI mapping functions conditional 2012-02-27 09:43:30 -06:00
ipcbuf.h asm-generic: add generic sysv ipc headers 2009-06-11 21:02:15 +02:00
irq.h asm-generic: add generic versions of common headers 2009-06-11 21:02:37 +02:00
irq_regs.h core: Replace __get_cpu_var with __this_cpu_read if not used for an address. 2010-12-17 15:07:19 +01:00
irqflags.h Fix IRQ flag handling naming 2010-10-07 14:08:55 +01:00
kdebug.h asm-generic: kdebug.h: Checkpatch cleanup 2010-10-09 21:51:44 +02:00
kmap_types.h include/asm-generic/kmap_types.h: add helpful reminder 2010-05-25 08:07:03 -07:00
kvm_para.h KVM: make asm-generic/kvm_para.h have an ifdef __KERNEL__ block 2012-05-21 17:47:52 +03:00
libata-portmap.h libata-portmap: Remove unused definitions 2007-10-12 14:55:37 -04:00
linkage.h asm-generic: add generic versions of common headers 2009-06-11 21:02:37 +02:00
local.h atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
local64.h atomic: use <linux/atomic.h> 2011-07-26 16:49:47 -07:00
memory_model.h mm: fix __page_to_pfn for a const struct page argument 2011-08-17 13:00:20 -07:00
mm_hooks.h
…
mman-common.h coredump: add VM_NODUMP, MADV_NODUMP, MADV_CLEAR_NODUMP 2012-03-23 16:58:42 -07:00
mman.h mm: add MAP_HUGETLB for mmaping pseudo-anonymous huge page regions 2009-09-22 07:17:41 -07:00
mmu.h asm-generic: add generic NOMMU versions of some headers 2009-06-11 21:02:50 +02:00
mmu_context.h asm-generic: add generic NOMMU versions of some headers 2009-06-11 21:02:50 +02:00
module.h asm-generic: add generic versions of common headers 2009-06-11 21:02:37 +02:00
msgbuf.h asm-generic: add generic sysv ipc headers 2009-06-11 21:02:15 +02:00
mutex-dec.h mutex: speed up generic mutex implementations 2008-10-23 09:18:20 -07:00
mutex-null.h
…
mutex-xchg.h mutex: speed up generic mutex implementations 2008-10-23 09:18:20 -07:00
mutex.h asm-generic: add generic versions of common headers 2009-06-11 21:02:37 +02:00
page.h The following changes since commit 3ee72ca992 2012-01-10 17:39:40 -08:00
param.h UAPI: Rearrange definition of HZ in asm-generic/param.h 2011-12-13 09:26:45 +00:00
parport.h asm-generic: add legacy I/O header files 2009-06-11 21:02:42 +02:00
pci-bridge.h PCI: work around Stratus ftServer broken PCIe hierarchy 2012-04-30 15:21:02 -06:00
pci-dma-compat.h dma-mapping: pci: move pci_set_dma_mask and pci_set_consistent_dma_mask to pci-dma-compat.h 2010-03-12 15:52:42 -08:00
pci.h PCI: collapse pcibios_resource_to_bus 2012-02-23 20:19:04 -07:00
pci_iomap.h [PARISC] fix compile break caused by iomap: make IOPORT/PCI mapping functions conditional 2012-02-27 09:43:30 -06:00
percpu.h percpu: Optimize __get_cpu_var() 2010-09-10 10:56:51 +02:00
pgalloc.h asm-generic: add generic NOMMU versions of some headers 2009-06-11 21:02:50 +02:00
pgtable-nopmd.h mm: Pass virtual address to [__]p{te,ud,md}_free_tlb() 2009-07-27 12:10:38 -07:00
pgtable-nopud.h mm: Pass virtual address to [__]p{te,ud,md}_free_tlb() 2009-07-27 12:10:38 -07:00
pgtable.h mm: pmd_read_atomic: fix 32bit PAE pmd walk vs pmd_populate SMP race condition 2012-05-29 16:22:24 -07:00
poll.h epoll: introduce POLLFREE to flush ->signalfd_wqh before kfree() 2012-02-24 11:42:50 -08:00
posix_types.h posix_types: Introduce __kernel_[u]long_t 2012-02-20 12:48:47 -08:00
ptrace.h asm-generic/ptrace.h: start a common low level ptrace helper 2011-05-26 17:12:36 -07:00
resource.h ulimit: raise default hard ulimit on number of files to 4096 2011-05-25 08:39:43 -07:00
rtc.h asm-generic: make get_rtc_time overridable 2009-06-11 21:02:18 +02:00
rwsem.h Hexagon: Add locking types and functions 2011-11-01 07:34:20 -07:00
scatterlist.h asm-generic: remove ARCH_HAS_SG_CHAIN in scatterlist.h 2010-05-27 09:12:54 -07:00
sections.h x86: Separate out entry text section 2011-03-08 17:22:11 +01:00
segment.h asm-generic: add generic NOMMU versions of some headers 2009-06-11 21:02:50 +02:00
sembuf.h asm-generic: add generic sysv ipc headers 2009-06-11 21:02:15 +02:00
serial.h asm-generic: add legacy I/O header files 2009-06-11 21:02:42 +02:00
setup.h asm-generic: add generic ABI headers 2009-06-11 21:02:15 +02:00
shmbuf.h asm-generic: add generic sysv ipc headers 2009-06-11 21:02:15 +02:00
shmparam.h asm-generic: add generic sysv ipc headers 2009-06-11 21:02:15 +02:00
siginfo.h Linux 3.4-rc5 2012-05-04 12:46:40 +10:00
signal-defs.h asm-generic: rename termios.h, signal.h and mman.h 2009-06-11 21:01:52 +02:00
signal.h asm-generic: add generic ABI headers 2009-06-11 21:02:15 +02:00
sizes.h asm-generic headers: add sizes.h 2011-03-17 09:19:04 +08:00
socket.h net: Add framework to allow sending packets with customized CRC. 2012-02-24 01:37:35 -08:00
sockios.h asm-generic: add generic ABI headers 2009-06-11 21:02:15 +02:00
spinlock.h asm-generic: add generic versions of common headers 2009-06-11 21:02:37 +02:00
stat.h asm-generic/stat.h: support 64-bit file time_t for stat() 2010-11-01 15:31:29 -04:00
statfs.h asm-generic: Use __BITS_PER_LONG in statfs.h 2012-04-30 12:55:15 -07:00
string.h asm-generic: add generic versions of common headers 2009-06-11 21:02:37 +02:00
swab.h asm-generic: add generic ABI headers 2009-06-11 21:02:15 +02:00
switch_to.h Split the switch_to() wrapper out of asm-generic/system.h 2012-03-28 18:30:03 +01:00
syscall.h asm/syscall.h: add syscall_get_arch 2012-04-14 11:13:19 +10:00
syscalls.h Fix the declaration of sys_execve() in asm-generic/syscalls.h 2010-08-18 12:12:38 -07:00
termbits.h tty: Add EXTPROC support for LINEMODE 2010-08-10 13:47:39 -07:00
termios-base.h asm-generic: rename termios.h, signal.h and mman.h 2009-06-11 21:01:52 +02:00
termios.h asm-generic: add generic ABI headers 2009-06-11 21:02:15 +02:00
timex.h asm-generic: add legacy I/O header files 2009-06-11 21:02:42 +02:00
tlb.h thp: add tlb_remove_pmd_tlb_entry 2012-01-12 20:13:08 -08:00
tlbflush.h BUG: headers with BUG/BUG_ON etc. need linux/bug.h 2012-03-04 17:54:34 -05:00
topology.h topology: alternate fix for ia64 tiger_defconfig build breakage 2010-08-09 20:44:57 -07:00
types.h consolidate umode_t declarations 2012-01-03 22:55:17 -05:00
uaccess-unaligned.h asm-generic: rename page.h and uaccess.h 2009-06-11 21:02:17 +02:00
uaccess.h fix default __strnlen_user macro 2011-10-06 19:47:12 -04:00
ucontext.h asm-generic: add generic ABI headers 2009-06-11 21:02:15 +02:00
unaligned.h asm-generic: add generic versions of common headers 2009-06-11 21:02:37 +02:00
unistd.h compat: use sys_sendfile64() implementation for sendfile syscall 2012-03-27 13:36:57 -04:00
user.h asm-generic/user.h: Fix spelling in comment 2011-03-01 15:49:39 +01:00
vga.h asm-generic: add legacy I/O header files 2009-06-11 21:02:42 +02:00
vmlinux.lds.h ftrace: Sort all function addresses, not just per page 2012-05-16 19:58:44 -04:00
word-at-a-time.h word-at-a-time: make the interfaces truly generic 2012-05-26 11:33:40 -07:00
xor.h sanitize <linux/prefetch.h> usage 2011-05-20 12:50:29 -07:00