[U-Boot] [PATCH V3 2/3] lib_generic memset: fill one word at a time if possible

[U-Boot] [PATCH V3 2/3] lib_generic memset: fill one word at a time if possible

[Alessandro Rubini]

From: Alessandro Rubini <rubini@unipv.it>

If the destination is aligned, fill ulong values until possible.
Then fill remaining part by bytes.

Signed-off-by: Alessandro Rubini <rubini@unipv.it>
Acked-by: Andrea Gallo <andrea.gallo@stericsson.com>
---
 lib_generic/string.c |   22 +++++++++++++++++++---
 1 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/lib_generic/string.c b/lib_generic/string.c
index 9bee79b..1575c63 100644
--- a/lib_generic/string.c
+++ b/lib_generic/string.c
@@ -403,10 +403,26 @@ char *strswab(const char *s)
  */
 void * memset(void * s,int c,size_t count)
 {
-	char *xs = (char *) s;
-
+	unsigned long *sl = (unsigned long *) s;
+	unsigned long cl = 0;
+	char *s8;
+	int i;
+
+	/* do it one word at a time (32 bits or 64 bits) while possible */
+	if ( ((count | (ulong)s) & (sizeof(*sl) - 1)) == 0) {
+		for (i=0; i<sizeof(*sl); ++i) {
+			cl <<= 8;
+			cl |= c & 0xff;
+		}
+		while (count >= sizeof(*sl)) {
+			*sl++ = cl;
+			count -= sizeof(*sl);
+		}
+	}
+	/* fill 8 bits at a time */
+	s8 = (char *)sl;
 	while (count--)
-		*xs++ = c;
+		*s8++ = c;
 
 	return s;
 }
-- 
1.5.6.5

[U-Boot] [PATCH V3 2/3] lib_generic memset: fill one word at a time if possible

[Chris Moore]

Similar remarks to those for memcpy :

Alessandro Rubini a ?crit :
> From: Alessandro Rubini <rubini@unipv.it>
>
> If the destination is aligned, fill ulong values until possible.
> Then fill remaining part by bytes.
>
> Signed-off-by: Alessandro Rubini <rubini@unipv.it>
> Acked-by: Andrea Gallo <andrea.gallo@stericsson.com>
> ---
>  lib_generic/string.c |   22 +++++++++++++++++++---
>  1 files changed, 19 insertions(+), 3 deletions(-)
>
> diff --git a/lib_generic/string.c b/lib_generic/string.c
> index 9bee79b..1575c63 100644
> --- a/lib_generic/string.c
> +++ b/lib_generic/string.c
> @@ -403,10 +403,26 @@ char *strswab(const char *s)
>   */
>  void * memset(void * s,int c,size_t count)
>  {
> -	char *xs = (char *) s;
> -
> +	unsigned long *sl = (unsigned long *) s;
>   

Nitpick: Cast ?

+	unsigned long *sl = s;


> +	unsigned long cl = 0;
> +	char *s8;
> +	int i;
> +
> +	/* do it one word at a time (32 bits or 64 bits) while possible */
> +	if ( ((count | (ulong)s) & (sizeof(*sl) - 1)) == 0) {
>   

Remove count from or.

+	if (((ulong)s & (sizeof(*sl) - 1)) == 0) {


> +		for (i=0; i<sizeof(*sl); ++i) {
>   

Nitpick: for LK spaces around operators are preferred but I am not sure 
for U-Boot.

+		for (i = 0; i < sizeof(*sl); ++i) {


> +			cl <<= 8;
> +			cl |= c & 0xff;
> +		}
> +		while (count >= sizeof(*sl)) {
> +			*sl++ = cl;
> +			count -= sizeof(*sl);
> +		}
> +	}
> +	/* fill 8 bits at a time */
> +	s8 = (char *)sl;
>  	while (count--)
> -		*xs++ = c;
> +		*s8++ = c;
>  
>  	return s;
>  }
>   

Cheers,
Chris