[U-Boot] [PATCH v5 1/5] lib: add rand() function

[Michael Walle]

Am Samstag 12 Mai 2012, 00:50:45 schrieb Michael Walle:
> It's a PRNG using the simple and fast xorshift method.
> 
> Signed-off-by: Michael Walle <michael at walle.cc>
> Cc: Wolfgang Denk <wd at denx.de>


Hi Wolfgang,

can you ack this patch? In that case i could add the acked-by line in the next 
version of this patch series to ease the picking by Prafulla. All your 
previous comments should be addressed :)


> ---
>  include/common.h |    6 ++++++
>  lib/Makefile     |    1 +
>  lib/rand.c       |   43 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 50 insertions(+), 0 deletions(-)
>  create mode 100644 lib/rand.c
> 
> diff --git a/include/common.h b/include/common.h
> index 4b5841e..a9cb62c 100644
> --- a/include/common.h
> +++ b/include/common.h
> @@ -733,6 +733,12 @@ char *	strmhz(char *buf, unsigned long hz);
>  /* lib/crc32.c */
>  #include <u-boot/crc.h>
> 
> +/* lib/rand.c */
> +#ifdef CONFIG_RANDOM_MACADDR
> +void srand(unsigned int seed);
> +unsigned int rand(void);
> +#endif
> +
>  /* common/console.c */
>  int	console_init_f(void);	/* Before relocation; uses the serial  stuff	
*/
>  int	console_init_r(void);	/* After  relocation; uses the console stuff	
*/
> diff --git a/lib/Makefile b/lib/Makefile
> index a0fec60..74579f9 100644
> --- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -65,6 +65,7 @@ COBJS-y += string.o
>  COBJS-y += time.o
>  COBJS-$(CONFIG_BOOTP_PXE) += uuid.o
>  COBJS-y += vsprintf.o
> +COBJS-$(CONFIG_RANDOM_MACADDR) += rand.o
> 
>  COBJS	:= $(COBJS-y)
>  SRCS	:= $(COBJS:.o=.c)
> diff --git a/lib/rand.c b/lib/rand.c
> new file mode 100644
> index 0000000..6cb76ac
> --- /dev/null
> +++ b/lib/rand.c
> @@ -0,0 +1,43 @@
> +/*
> + * Simple xorshift PRNG
> + *   see http://www.jstatsoft.org/v08/i14/paper
> + *
> + * Copyright (c) 2012 Michael Walle
> + * Michael Walle <michael at walle.cc>
> + *
> + * See file CREDITS for list of people who contributed to this
> + * project.
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
> + * MA 02111-1307 USA
> + */
> +
> +#include <common.h>
> +
> +static unsigned int y = 1U;
> +
> +void srand(unsigned int seed)
> +{
> +	y = seed;
> +}
> +
> +unsigned int rand(void)
> +{
> +	y ^= (y << 13);
> +	y ^= (y >> 17);
> +	y ^= (y << 5);
> +
> +	return y;
> +}


-- 
Michael