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ee146c1c10
linux/arch/m32r/Kconfig
Zhaoxiu Zeng fff7fb0b2d lib/GCD.c: use binary GCD algorithm instead of Euclidean 
The binary GCD algorithm is based on the following facts:
	1. If a and b are all evens, then gcd(a,b) = 2 * gcd(a/2, b/2)
	2. If a is even and b is odd, then gcd(a,b) = gcd(a/2, b)
	3. If a and b are all odds, then gcd(a,b) = gcd((a-b)/2, b) = gcd((a+b)/2, b)

Even on x86 machines with reasonable division hardware, the binary
algorithm runs about 25% faster (80% the execution time) than the
division-based Euclidian algorithm.

On platforms like Alpha and ARMv6 where division is a function call to
emulation code, it's even more significant.

There are two variants of the code here, depending on whether a fast
__ffs (find least significant set bit) instruction is available.  This
allows the unpredictable branches in the bit-at-a-time shifting loop to
be eliminated.

If fast __ffs is not available, the "even/odd" GCD variant is used.

I use the following code to benchmark:

	#include <stdio.h>
	#include <stdlib.h>
	#include <stdint.h>
	#include <string.h>
	#include <time.h>
	#include <unistd.h>

	#define swap(a, b) \
		do { \
			a ^= b; \
			b ^= a; \
			a ^= b; \
		} while (0)

	unsigned long gcd0(unsigned long a, unsigned long b)
	{
		unsigned long r;

		if (a < b) {
			swap(a, b);
		}

		if (b == 0)
			return a;

		while ((r = a % b) != 0) {
			a = b;
			b = r;
		}

		return b;
	}

	unsigned long gcd1(unsigned long a, unsigned long b)
	{
		unsigned long r = a | b;

		if (!a || !b)
			return r;

		b >>= __builtin_ctzl(b);

		for (;;) {
			a >>= __builtin_ctzl(a);
			if (a == b)
				return a << __builtin_ctzl(r);

			if (a < b)
				swap(a, b);
			a -= b;
		}
	}

	unsigned long gcd2(unsigned long a, unsigned long b)
	{
		unsigned long r = a | b;

		if (!a || !b)
			return r;

		r &= -r;

		while (!(b & r))
			b >>= 1;

		for (;;) {
			while (!(a & r))
				a >>= 1;
			if (a == b)
				return a;

			if (a < b)
				swap(a, b);
			a -= b;
			a >>= 1;
			if (a & r)
				a += b;
			a >>= 1;
		}
	}

	unsigned long gcd3(unsigned long a, unsigned long b)
	{
		unsigned long r = a | b;

		if (!a || !b)
			return r;

		b >>= __builtin_ctzl(b);
		if (b == 1)
			return r & -r;

		for (;;) {
			a >>= __builtin_ctzl(a);
			if (a == 1)
				return r & -r;
			if (a == b)
				return a << __builtin_ctzl(r);

			if (a < b)
				swap(a, b);
			a -= b;
		}
	}

	unsigned long gcd4(unsigned long a, unsigned long b)
	{
		unsigned long r = a | b;

		if (!a || !b)
			return r;

		r &= -r;

		while (!(b & r))
			b >>= 1;
		if (b == r)
			return r;

		for (;;) {
			while (!(a & r))
				a >>= 1;
			if (a == r)
				return r;
			if (a == b)
				return a;

			if (a < b)
				swap(a, b);
			a -= b;
			a >>= 1;
			if (a & r)
				a += b;
			a >>= 1;
		}
	}

	static unsigned long (*gcd_func[])(unsigned long a, unsigned long b) = {
		gcd0, gcd1, gcd2, gcd3, gcd4,
	};

	#define TEST_ENTRIES (sizeof(gcd_func) / sizeof(gcd_func[0]))

	#if defined(__x86_64__)

	#define rdtscll(val) do { \
		unsigned long __a,__d; \
		__asm__ __volatile__("rdtsc" : "=a" (__a), "=d" (__d)); \
		(val) = ((unsigned long long)__a) | (((unsigned long long)__d)<<32); \
	} while(0)

	static unsigned long long benchmark_gcd_func(unsigned long (*gcd)(unsigned long, unsigned long),
								unsigned long a, unsigned long b, unsigned long *res)
	{
		unsigned long long start, end;
		unsigned long long ret;
		unsigned long gcd_res;

		rdtscll(start);
		gcd_res = gcd(a, b);
		rdtscll(end);

		if (end >= start)
			ret = end - start;
		else
			ret = ~0ULL - start + 1 + end;

		*res = gcd_res;
		return ret;
	}

	#else

	static inline struct timespec read_time(void)
	{
		struct timespec time;
		clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &time);
		return time;
	}

	static inline unsigned long long diff_time(struct timespec start, struct timespec end)
	{
		struct timespec temp;

		if ((end.tv_nsec - start.tv_nsec) < 0) {
			temp.tv_sec = end.tv_sec - start.tv_sec - 1;
			temp.tv_nsec = 1000000000ULL + end.tv_nsec - start.tv_nsec;
		} else {
			temp.tv_sec = end.tv_sec - start.tv_sec;
			temp.tv_nsec = end.tv_nsec - start.tv_nsec;
		}

		return temp.tv_sec * 1000000000ULL + temp.tv_nsec;
	}

	static unsigned long long benchmark_gcd_func(unsigned long (*gcd)(unsigned long, unsigned long),
								unsigned long a, unsigned long b, unsigned long *res)
	{
		struct timespec start, end;
		unsigned long gcd_res;

		start = read_time();
		gcd_res = gcd(a, b);
		end = read_time();

		*res = gcd_res;
		return diff_time(start, end);
	}

	#endif

	static inline unsigned long get_rand()
	{
		if (sizeof(long) == 8)
			return (unsigned long)rand() << 32 | rand();
		else
			return rand();
	}

	int main(int argc, char **argv)
	{
		unsigned int seed = time(0);
		int loops = 100;
		int repeats = 1000;
		unsigned long (*res)[TEST_ENTRIES];
		unsigned long long elapsed[TEST_ENTRIES];
		int i, j, k;

		for (;;) {
			int opt = getopt(argc, argv, "n:r:s:");
			/* End condition always first */
			if (opt == -1)
				break;

			switch (opt) {
			case 'n':
				loops = atoi(optarg);
				break;
			case 'r':
				repeats = atoi(optarg);
				break;
			case 's':
				seed = strtoul(optarg, NULL, 10);
				break;
			default:
				/* You won't actually get here. */
				break;
			}
		}

		res = malloc(sizeof(unsigned long) * TEST_ENTRIES * loops);
		memset(elapsed, 0, sizeof(elapsed));

		srand(seed);
		for (j = 0; j < loops; j++) {
			unsigned long a = get_rand();
			/* Do we have args? */
			unsigned long b = argc > optind ? strtoul(argv[optind], NULL, 10) : get_rand();
			unsigned long long min_elapsed[TEST_ENTRIES];
			for (k = 0; k < repeats; k++) {
				for (i = 0; i < TEST_ENTRIES; i++) {
					unsigned long long tmp = benchmark_gcd_func(gcd_func[i], a, b, &res[j][i]);
					if (k == 0 || min_elapsed[i] > tmp)
						min_elapsed[i] = tmp;
				}
			}
			for (i = 0; i < TEST_ENTRIES; i++)
				elapsed[i] += min_elapsed[i];
		}

		for (i = 0; i < TEST_ENTRIES; i++)
			printf("gcd%d: elapsed %llu\n", i, elapsed[i]);

		k = 0;
		srand(seed);
		for (j = 0; j < loops; j++) {
			unsigned long a = get_rand();
			unsigned long b = argc > optind ? strtoul(argv[optind], NULL, 10) : get_rand();
			for (i = 1; i < TEST_ENTRIES; i++) {
				if (res[j][i] != res[j][0])
					break;
			}
			if (i < TEST_ENTRIES) {
				if (k == 0) {
					k = 1;
					fprintf(stderr, "Error:\n");
				}
				fprintf(stderr, "gcd(%lu, %lu): ", a, b);
				for (i = 0; i < TEST_ENTRIES; i++)
					fprintf(stderr, "%ld%s", res[j][i], i < TEST_ENTRIES - 1 ? ", " : "\n");
			}
		}

		if (k == 0)
			fprintf(stderr, "PASS\n");

		free(res);

		return 0;
	}

Compiled with "-O2", on "VirtualBox 4.4.0-22-generic #38-Ubuntu x86_64" got:

  zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10
  gcd0: elapsed 10174
  gcd1: elapsed 2120
  gcd2: elapsed 2902
  gcd3: elapsed 2039
  gcd4: elapsed 2812
  PASS
  zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10
  gcd0: elapsed 9309
  gcd1: elapsed 2280
  gcd2: elapsed 2822
  gcd3: elapsed 2217
  gcd4: elapsed 2710
  PASS
  zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10
  gcd0: elapsed 9589
  gcd1: elapsed 2098
  gcd2: elapsed 2815
  gcd3: elapsed 2030
  gcd4: elapsed 2718
  PASS
  zhaoxiuzeng@zhaoxiuzeng-VirtualBox:~/develop$ ./gcd -r 500000 -n 10
  gcd0: elapsed 9914
  gcd1: elapsed 2309
  gcd2: elapsed 2779
  gcd3: elapsed 2228
  gcd4: elapsed 2709
  PASS

[akpm@linux-foundation.org: avoid #defining a CONFIG_ variable]
Signed-off-by: Zhaoxiu Zeng <zhaoxiu.zeng@gmail.com>
Signed-off-by: George Spelvin <linux@horizon.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-20 17:58:30 -07:00

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config M32R
bool
default y
select HAVE_IDE
select HAVE_OPROFILE
select INIT_ALL_POSSIBLE
select HAVE_KERNEL_GZIP
select HAVE_KERNEL_BZIP2
select HAVE_KERNEL_LZMA
select ARCH_WANT_IPC_PARSE_VERSION
select HAVE_DEBUG_BUGVERBOSE
select VIRT_TO_BUS
select GENERIC_IRQ_PROBE
select GENERIC_IRQ_SHOW
select GENERIC_ATOMIC64
select ARCH_HAS_DEVMEM_IS_ALLOWED
select ARCH_USES_GETTIMEOFFSET
select MODULES_USE_ELF_RELA
select HAVE_DEBUG_STACKOVERFLOW
select CPU_NO_EFFICIENT_FFS
config SBUS
bool
config GENERIC_ISA_DMA
bool
default y
config ZONE_DMA
bool
default y
config NO_IOPORT_MAP
def_bool y
config NO_DMA
def_bool y
config HZ
int
default 100
source "init/Kconfig"
source "kernel/Kconfig.freezer"
menu "Processor type and features"
choice
prompt "Platform Type"
default PLAT_MAPPI
config PLAT_MAPPI
bool "Mappi-I"
help
The Mappi-I is an FPGA board for SOC (System-On-a-Chip) prototyping.
You can operate a Linux system on this board by using an M32R
softmacro core, which is a fully-synthesizable functional model
described in Verilog-HDL.
The Mappi-I board was the first platform, which had been used
to port and develop a Linux system for the M32R processor.
Currently, the Mappi-II, an heir to the Mappi-I, is available.
config PLAT_USRV
bool "uServer"
select PLAT_HAS_INT1ICU
config PLAT_M32700UT
bool "M32700UT"
select PLAT_HAS_INT0ICU
select PLAT_HAS_INT1ICU
select PLAT_HAS_INT2ICU
help
The M3T-M32700UT is an evaluation board based on uT-Engine
specification. This board has an M32700 (Chaos) evaluation chip.
You can say Y for SMP, because the M32700 is a single chip
multiprocessor.
config PLAT_OPSPUT
bool "OPSPUT"
select PLAT_HAS_INT0ICU
select PLAT_HAS_INT1ICU
select PLAT_HAS_INT2ICU
help
The OPSPUT is an evaluation board based on uT-Engine
specification. This board has a OPSP-REP chip.
config PLAT_OAKS32R
bool "OAKS32R"
help
The OAKS32R is a tiny, inexpensive evaluation board.
Please note that if you say Y here and choose chip "M32102",
say N for MMU and select a no-MMU version kernel, otherwise
a kernel with MMU support will not work, because the M32102
is a microcontroller for embedded systems and it has no MMU.
config PLAT_MAPPI2
bool "Mappi-II(M3A-ZA36/M3A-ZA52)"
config PLAT_MAPPI3
bool "Mappi-III(M3A-2170)"
config PLAT_M32104UT
bool "M32104UT"
select PLAT_HAS_INT1ICU
help
The M3T-M32104UT is an reference board based on uT-Engine
specification. This board has a M32104 chip.
endchoice
choice
prompt "Processor family"
default CHIP_M32700
config CHIP_M32700
bool "M32700 (Chaos)"
config CHIP_M32102
bool "M32102"
config CHIP_M32104
bool "M32104"
depends on PLAT_M32104UT
config CHIP_VDEC2
bool "VDEC2"
config CHIP_OPSP
bool "OPSP"
endchoice
config MMU
bool "Support for memory management hardware"
depends on CHIP_M32700 || CHIP_VDEC2 || CHIP_OPSP
default y
config TLB_ENTRIES
int "TLB Entries"
depends on CHIP_M32700 || CHIP_VDEC2 || CHIP_OPSP
default 32 if CHIP_M32700 || CHIP_OPSP
default 16 if CHIP_VDEC2
config ISA_M32R
bool
depends on CHIP_M32102 || CHIP_M32104
default y
config ISA_M32R2
bool
depends on CHIP_M32700 || CHIP_VDEC2 || CHIP_OPSP
default y
config ISA_DSP_LEVEL2
bool
depends on CHIP_M32700 || CHIP_OPSP
default y
config ISA_DUAL_ISSUE
bool
depends on CHIP_M32700 || CHIP_OPSP
default y
config PLAT_HAS_INT0ICU
bool
default n
config PLAT_HAS_INT1ICU
bool
default n
config PLAT_HAS_INT2ICU
bool
default n
config BUS_CLOCK
int "Bus Clock [Hz] (integer)"
default "70000000" if PLAT_MAPPI
default "25000000" if PLAT_USRV
default "50000000" if PLAT_MAPPI3
default "50000000" if PLAT_M32700UT
default "50000000" if PLAT_OPSPUT
default "54000000" if PLAT_M32104UT
default "33333333" if PLAT_OAKS32R
default "20000000" if PLAT_MAPPI2
config TIMER_DIVIDE
int "Timer divider (integer)"
default "128"
config CPU_LITTLE_ENDIAN
bool "Generate little endian code"
default n
config MEMORY_START
hex "Physical memory start address (hex)"
default "08000000" if PLAT_MAPPI || PLAT_MAPPI2 || PLAT_MAPPI3
default "08000000" if PLAT_USRV
default "08000000" if PLAT_M32700UT
default "08000000" if PLAT_OPSPUT
default "04000000" if PLAT_M32104UT
default "01000000" if PLAT_OAKS32R
config MEMORY_SIZE
hex "Physical memory size (hex)"
default "08000000" if PLAT_MAPPI3
default "04000000" if PLAT_MAPPI || PLAT_MAPPI2
default "02000000" if PLAT_USRV
default "01000000" if PLAT_M32700UT
default "01000000" if PLAT_OPSPUT
default "01000000" if PLAT_M32104UT
default "00800000" if PLAT_OAKS32R
config ARCH_DISCONTIGMEM_ENABLE
bool "Internal RAM Support"
depends on CHIP_M32700 || CHIP_M32102 || CHIP_VDEC2 || CHIP_OPSP || CHIP_M32104
default y
source "mm/Kconfig"
config IRAM_START
hex "Internal memory start address (hex)"
default "00f00000" if !CHIP_M32104
default "00700000" if CHIP_M32104
depends on (CHIP_M32700 || CHIP_M32102 || CHIP_VDEC2 || CHIP_OPSP || CHIP_M32104) && DISCONTIGMEM
config IRAM_SIZE
hex "Internal memory size (hex)"
depends on (CHIP_M32700 || CHIP_M32102 || CHIP_VDEC2 || CHIP_OPSP || CHIP_M32104) && DISCONTIGMEM
default "00080000" if CHIP_M32700
default "00010000" if CHIP_M32102 || CHIP_OPSP || CHIP_M32104
default "00008000" if CHIP_VDEC2
#
# Define implied options from the CPU selection here
#
config GENERIC_LOCKBREAK
bool
default y
depends on SMP && PREEMPT
config RWSEM_GENERIC_SPINLOCK
bool
depends on M32R
default y
config RWSEM_XCHGADD_ALGORITHM
bool
default n
config ARCH_HAS_ILOG2_U32
bool
default n
config ARCH_HAS_ILOG2_U64
bool
default n
config GENERIC_HWEIGHT
bool
default y
config GENERIC_CALIBRATE_DELAY
bool
default y
config SCHED_OMIT_FRAME_POINTER
bool
default y
source "kernel/Kconfig.preempt"
config SMP
bool "Symmetric multi-processing support"
depends on MMU
---help---
This enables support for systems with more than one CPU. If you have
a system with only one CPU, say N. If you have a system with more
than one CPU, say Y.
If you say N here, the kernel will run on uni- and multiprocessor
machines, but will use only one CPU of a multiprocessor machine. If
you say Y here, the kernel will run on many, but not all,
uniprocessor machines. On a uniprocessor machine, the kernel
will run faster if you say N here.
People using multiprocessor machines who say Y here should also say
Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
Management" code will be disabled if you say Y here.
See also the SMP-HOWTO available at
<http://tldp.org/HOWTO/SMP-HOWTO.html>.
If you don't know what to do here, say N.
config CHIP_M32700_TS1
bool "Workaround code for the M32700 TS1 chip's bug"
depends on (CHIP_M32700 && SMP)
default n
config NR_CPUS
int "Maximum number of CPUs (2-32)"
range 2 32
depends on SMP
default "2"
help
This allows you to specify the maximum number of CPUs which this
kernel will support. The maximum supported value is 32 and the
minimum value which makes sense is 2.
This is purely to save memory - each supported CPU adds
approximately eight kilobytes to the kernel image.
# Common NUMA Features
config NUMA
bool "Numa Memory Allocation Support"
depends on SMP && BROKEN
default n
config NODES_SHIFT
int
default "1"
depends on NEED_MULTIPLE_NODES
endmenu
menu "Bus options (PCI, PCMCIA, EISA, MCA, ISA)"
config PCI
bool "PCI support"
depends on BROKEN
default n
help
Find out whether you have a PCI motherboard. PCI is the name of a
bus system, i.e. the way the CPU talks to the other stuff inside
your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
VESA. If you have PCI, say Y, otherwise N.
choice
prompt "PCI access mode"
depends on PCI
default PCI_GOANY
config PCI_GOBIOS
bool "BIOS"
---help---
On PCI systems, the BIOS can be used to detect the PCI devices and
determine their configuration. However, some old PCI motherboards
have BIOS bugs and may crash if this is done. Also, some embedded
PCI-based systems don't have any BIOS at all. Linux can also try to
detect the PCI hardware directly without using the BIOS.
With this option, you can specify how Linux should detect the PCI
devices. If you choose "BIOS", the BIOS will be used, if you choose
"Direct", the BIOS won't be used, and if you choose "Any", the
kernel will try the direct access method and falls back to the BIOS
if that doesn't work. If unsure, go with the default, which is
"Any".
config PCI_GODIRECT
bool "Direct"
config PCI_GOANY
bool "Any"
endchoice
config PCI_BIOS
bool
depends on PCI && (PCI_GOBIOS || PCI_GOANY)
default y
config PCI_DIRECT
bool
depends on PCI && (PCI_GODIRECT || PCI_GOANY)
default y
source "drivers/pci/Kconfig"
config ISA
bool
source "drivers/pcmcia/Kconfig"
endmenu
menu "Executable file formats"
source "fs/Kconfig.binfmt"
endmenu
source "net/Kconfig"
source "drivers/Kconfig"
source "fs/Kconfig"
source "arch/m32r/Kconfig.debug"
source "security/Kconfig"
source "crypto/Kconfig"
source "lib/Kconfig"
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