diff --git a/ChangeLog b/ChangeLog
index 313d8865f780c0cdb5a34fb5363d92a711100422..82a4fd092695a68c9d730cfdca65497db7f8658a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -3490,4 +3490,7 @@
the ARMv7-M family contributed by Mike Smith.
* lib/strings/lib_vikmemcpy.c: As an option, the larger but faster
implemementation of memcpy from Daniel Vik is now available (this is
- from http://www.danielvik.com/2010/02/fast-memcpy-in-c.html).
\ No newline at end of file
+ from http://www.danielvik.com/2010/02/fast-memcpy-in-c.html).
+ * lib/strings/lib_memset.c: CONFIG_MEMSET_OPTSPEED will select a
+ version of memset() optimized for speed. By default, memset() is
+ optimized for size.
diff --git a/Documentation/NuttShell.html b/Documentation/NuttShell.html
index ad204f5dc9772236d6525723db55f48da610a477..78a565107401e27482abb6950b34e0cb2260b16f 100644
--- a/Documentation/NuttShell.html
+++ b/Documentation/NuttShell.html
@@ -8,7 +8,7 @@
<tr align="center" bgcolor="#e4e4e4">
<td>
<h1><big><font color="#3c34ec"><i>NuttShell (NSH)</i></font></big></h1>
- <p>Last Updated: August 28, 2012</p>
+ <p>Last Updated: October 20, 2012</p>
</td>
</tr>
</table>
diff --git a/Documentation/NuttxPortingGuide.html b/Documentation/NuttxPortingGuide.html
index a16032db5757771e2052e2da10e1a7f8b97308dc..e43ca8a2fa0eade64af17a0c8a6b41635b1dcd3c 100644
--- a/Documentation/NuttxPortingGuide.html
+++ b/Documentation/NuttxPortingGuide.html
@@ -12,7 +12,7 @@
<h1><big><font color="#3c34ec">
<i>NuttX RTOS Porting Guide</i>
</font></big></h1>
- <p>Last Updated: August 28, 2012</p>
+ <p>Last Updated: October 20, 2012</p>
</td>
</tr>
</table>
@@ -4449,12 +4449,12 @@ build
If <code>CONFIG_ARCH_MEMCPY</code> is <b>not</b> selected, then you make also select Daniel
Vik's optimized implementation of <code>memcpy()</code>:
</p>
- <ul><li>
- <code>CONFIG_MEMCPY_VIK</code>:
- Select this option to use the optimized <code>memcpy()</code> function by Daniel Vik.
- See licensing information in the top-level <code>COPYING</code> file.
- Default: <code>n</code>.
- </li></ul>
+<ul><li>
+ <code>CONFIG_MEMCPY_VIK</code>:
+ Select this option to use the optimized <code>memcpy()</code> function by Daniel Vik.
+ See licensing information in the top-level <code>COPYING</code> file.
+ Default: <code>n</code>.
+</li></ul>
<p>
And if <code>CONFIG_MEMCPY_VIK</code>, the following tuning options are available:
@@ -4474,6 +4474,15 @@ build
Compiles memcpy for 64 bit architectures
</li></ul>
+<p><li>
+ If <code>CONFIG_ARCH_MEMSET</code> is <b>not</b> selected, then the following option is also available:
+</p>
+<ul><li>
+ <code>CONFIG_MEMSET_OPTSPEED</code>:
+ Select this option to use a version of <code>memset()</code> optimized for speed.
+ Default: <code>memset()</code> is optimized for size.
+</li></ul>
+
<li>
<p>
The architecture may provide custom versions of certain standard header files:
diff --git a/configs/README.txt b/configs/README.txt
index cc65540d7fe02b62722c67458b051e7385baf840..0bb531d67a4108a7c4d22bb03546e795655adf8b 100644
--- a/configs/README.txt
+++ b/configs/README.txt
@@ -638,6 +638,12 @@ defconfig -- This is a configuration file similar to the Linux
CONFIG_MEMCPY_64BIT - Compiles memcpy for 64 bit architectures
+ If CONFIG_ARCH_MEMSET is not selected, then the following option is
+ also available:
+
+ CONFIG_MEMSET_OPTSPEED - Select this option to use a version of memcpy()
+ optimized for speed. Default: memcpy() is optimized for size.
+
The architecture may provide custom versions of certain standard header
files:
diff --git a/lib/Kconfig b/lib/Kconfig
index b3f743db28b05396d7ca9ca56bf78b46951e54e1..0f25c89238f13dbe233247b13b63fbc599315a13 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -153,19 +153,20 @@ config ARCH_OPTIMIZED_FUNCTIONS
if ARCH_OPTIMIZED_FUNCTIONS
config ARCH_MEMCPY
- bool "memcpy"
+ bool "memcpy()"
default n
---help---
Select this option if the architecture provides an optimized version
of memcpy().
config MEMCPY_VIK
- bool "Vik memcpy"
+ bool "Vik memcpy()"
default n
depends on !ARCH_MEMCPY
---help---
- Select this option to use the optimized memcpy() function by Daniel Vik.
- See licensing information in the top-level COPYING file.
+ Select this option to use the optimized memcpy() function by Daniel Vik.
+ Select this option to option for speed at the expense of increased size.
+ See licensing information in the top-level COPYING file.
if MEMCPY_VIK
config MEMCPY_PRE_INC_PTRS
@@ -182,50 +183,58 @@ config MEMCPY_INDEXED_COPY
MEMCPY_PRE_INC_PTRS option.
config MEMCPY_64BIT
- bool "64-bit memcpy"
+ bool "64-bit memcpy()"
default n
---help---
- Compiles memcpy for 64 bit architectures
+ Compiles memcpy() for 64 bit architectures
endif
config ARCH_MEMCMP
- bool "memcmp"
+ bool "memcmp()"
default n
---help---
Select this option if the architecture provides an optimized version
of memcmp().
config ARCH_MEMMOVE
- bool "memmove"
+ bool "memmove()"
default n
---help---
Select this option if the architecture provides an optimized version
of memmove().
config ARCH_MEMSET
- bool "memset"
+ bool "memset()"
default n
---help---
Select this option if the architecture provides an optimized version
of memset().
+config MEMSET_OPTSPEED
+ bool "Optimize memset() for speed"
+ default n
+ depends on !ARCH_MEMSET
+ ---help---
+ Select this option to use a version of memcpy() optimized for speed.
+ Default: memcpy() is optimized for size.
+
config ARCH_STRCMP
- bool "strcmp"
+ bool "strcmp()"
default n
---help---
Select this option if the architecture provides an optimized version
of strcmp().
config ARCH_STRCPY
- bool "strcpy"
+ bool "strcpy()"
default n
---help---
Select this option if the architecture provides an optimized version
of strcpy().
config ARCH_STRNCPY
- bool "strncpy"
+ bool "strncpy()"
default n
---help---
Select this option if the architecture provides an optimized version
@@ -239,14 +248,14 @@ config ARCH_STRLEN
of strlen().
config ARCH_STRNLEN
- bool "strlen"
+ bool "strlen()"
default n
---help---
Select this option if the architecture provides an optimized version
of strnlen().
config ARCH_BZERO
- bool "bzero"
+ bool "bzero()"
default n
---help---
Select this option if the architecture provides an optimized version
diff --git a/lib/string/lib_memset.c b/lib/string/lib_memset.c
index 916351b974ab090ad1b9a94b646f2c228a7efb43..c910d2ce042f029a5f5a6b76ac85f48f8a331bd2 100644
--- a/lib/string/lib_memset.c
+++ b/lib/string/lib_memset.c
@@ -42,8 +42,12 @@
************************************************************/
#include <nuttx/config.h>
+
#include <sys/types.h>
+
+#include <stdint.h>
#include <string.h>
+#include <assert.h>
/************************************************************
* Global Functions
@@ -52,8 +56,88 @@
#ifndef CONFIG_ARCH_MEMSET
void *memset(void *s, int c, size_t n)
{
+#ifdef CONFIG_MEMSET_OPTSPEED
+ /* This version is optimized for speed (you could do better
+ * still by exploiting processor caching or memory burst
+ * knowledge. 64-bit support might improve performance as
+ * well.
+ */
+
+ uintptr_t addr = (uintptr_t)s;
+ uint16_t val16 = ((uint16_t)c << 8) | (uint16_t)c;
+ uint32_t val32 = ((uint32_t)val16 << 16) | (uint32_t)val16;
+
+ /* Make sure that there is something to be cleared */
+
+ if (n > 0)
+ {
+ /* Align to a 16-bit boundary */
+
+ if ((addr & 1) != 0)
+ {
+ *(uint8_t*)addr = (uint8_t)c;
+ addr += 1;
+ n -= 1;
+ }
+
+ /* Check if there are at least 16-bits left to be zeroed */
+
+ if (n >= 2)
+ {
+ /* Align to a 32-bit boundary (we know that the destination
+ * address is already aligned to at least a 16-bit boundary).
+ */
+
+ if ((addr & 3) != 0)
+ {
+ *(uint16_t*)addr = val16;
+ addr += 2;
+ n -= 2;
+ }
+
+ /* Loop while there are at least 32-bits left to be zeroed */
+
+ while (n >= 4)
+ {
+ *(uint32_t*)addr = val32;
+ addr += 4;
+ n -= 4;
+ }
+ }
+
+ /* We may get here under the following conditions:
+ *
+ * n = 0, addr may or may not be aligned
+ * n = 1, addr may or may not be aligned
+ * n = 2, addr is aligned to a 32-bit boundary
+ * n = 3, addr is aligned to a 32-bit boundary
+ */
+
+ switch (n)
+ {
+ default:
+ case 0:
+ DEBUGASSERT(n == 0);
+ break;
+
+ case 2:
+ *(uint16_t*)addr = val16;
+ break;
+
+ case 3:
+ *(uint16_t*)addr = val16;
+ addr += 2;
+ case 1:
+ *(uint8_t*)addr = (uint8_t)c;
+ break;
+ }
+ }
+#else
+ /* This version is optimized for size */
+
unsigned char *p = (unsigned char*)s;
while (n-- > 0) *p++ = c;
+#endif
return s;
}
#endif