coreboot-kgpe-d16/src/arch/x86/lib/memcpy.c

#include <string.h>

void *memcpy(void *dest, const void *src, size_t n)
{
	unsigned long d0, d1, d2;

	asm volatile(
		"rep movsb"
		: "=S"(d0), "=D"(d1), "=c"(d2)
		: "0"(src), "1"(dest), "2"(n)
		: "memory"
		);

	return dest;
}
Add faster, architecture dependent memcpy() Change-Id: I38d15f3f1ec65f0cb7974d2dd4ae6356433bddd8 Signed-off-by: Stefan Reinauer <reinauer@google.com> Reviewed-by: Duncan Laurie <dlaurie@google.com> Reviewed-on: http://review.coreboot.org/736 Reviewed-by: Ronald G. Minnich <rminnich@gmail.com> Tested-by: build bot (Jenkins) 2011-10-26 01:43:34 +02:00			`#include <string.h>`

Fix issues with x86 memcpy The x86 memcpy() implementation did not mention its implicit output registers ESI, EDI and ECX which might make this code miscompile when the compiler uses the value of EDI for the return value after the 'rep movsb' has completed. That would break the API of memcpy as this would return 'dst+len' instead of 'dst'. Fix this possible bug by removing the wrong comment and listing all output registers as such (using dummy stack variables that get optimized away). Also the leading 'cld' is superflous as the ABI mandates the direction flag to be cleared all the time when we're in C (see <http://gcc.gnu.org/gcc-4.3/changes.html>) and we have no ASM call sites that might require it to be cleared explicitly (SMM might come to mind, but it clears the DF itself before passing control to the C part of the SMI handler). Last but not least fix the prototype to match the one from <string.h>. Change-Id: I106422d41180c4ed876078cabb26b45e49f3fa93 Signed-off-by: Mathias Krause <minipli@googlemail.com> Reviewed-on: http://review.coreboot.org/836 Tested-by: build bot (Jenkins) Reviewed-by: Peter Stuge <peter@stuge.se> 2012-03-31 17:23:53 +02:00			`void memcpy(void dest, const void *src, size_t n)`
Add faster, architecture dependent memcpy() Change-Id: I38d15f3f1ec65f0cb7974d2dd4ae6356433bddd8 Signed-off-by: Stefan Reinauer <reinauer@google.com> Reviewed-by: Duncan Laurie <dlaurie@google.com> Reviewed-on: http://review.coreboot.org/736 Reviewed-by: Ronald G. Minnich <rminnich@gmail.com> Tested-by: build bot (Jenkins) 2011-10-26 01:43:34 +02:00			`{`
Fix issues with x86 memcpy The x86 memcpy() implementation did not mention its implicit output registers ESI, EDI and ECX which might make this code miscompile when the compiler uses the value of EDI for the return value after the 'rep movsb' has completed. That would break the API of memcpy as this would return 'dst+len' instead of 'dst'. Fix this possible bug by removing the wrong comment and listing all output registers as such (using dummy stack variables that get optimized away). Also the leading 'cld' is superflous as the ABI mandates the direction flag to be cleared all the time when we're in C (see <http://gcc.gnu.org/gcc-4.3/changes.html>) and we have no ASM call sites that might require it to be cleared explicitly (SMM might come to mind, but it clears the DF itself before passing control to the C part of the SMI handler). Last but not least fix the prototype to match the one from <string.h>. Change-Id: I106422d41180c4ed876078cabb26b45e49f3fa93 Signed-off-by: Mathias Krause <minipli@googlemail.com> Reviewed-on: http://review.coreboot.org/836 Tested-by: build bot (Jenkins) Reviewed-by: Peter Stuge <peter@stuge.se> 2012-03-31 17:23:53 +02:00			`unsigned long d0, d1, d2;`

			`asm volatile(`
			`"rep movsb"`
			`: "=S"(d0), "=D"(d1), "=c"(d2)`
			`: "0"(src), "1"(dest), "2"(n)`
			`: "memory"`
			`);`

			`return dest;`
Add faster, architecture dependent memcpy() Change-Id: I38d15f3f1ec65f0cb7974d2dd4ae6356433bddd8 Signed-off-by: Stefan Reinauer <reinauer@google.com> Reviewed-by: Duncan Laurie <dlaurie@google.com> Reviewed-on: http://review.coreboot.org/736 Reviewed-by: Ronald G. Minnich <rminnich@gmail.com> Tested-by: build bot (Jenkins) 2011-10-26 01:43:34 +02:00			`}`