[PATCH] cmd/mem.c: use memmove in do_mem_cp()
There's no 'mv' shell command for handling overlapping src and dst regions, and there's no point introducing one, when we can just make the existing 'cp' command DTRT in all cases. memmove() should at most be a few instructions more then memcpy() (to detect the appropriate direction to do the copy), which is of course completely in the noise with all the string processing that a shell command does.
Signed-off-by: Rasmus Villemoes rasmus.villemoes@prevas.dk --- cmd/mem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/cmd/mem.c b/cmd/mem.c index 66c2d36a148..c696b92a274 100644 --- a/cmd/mem.c +++ b/cmd/mem.c @@ -361,7 +361,7 @@ static int do_mem_cp(struct cmd_tbl *cmdtp, int flag, int argc, } #endif
- memcpy(dst, src, count * size); + memmove(dst, src, count * size);
unmap_sysmem(src); unmap_sysmem(dst);
Hi Rasmus,
On Tue, Dec 19, 2023 at 11:57 AM Rasmus Villemoes rasmus.villemoes@prevas.dk wrote:
There's no 'mv' shell command for handling overlapping src and dst regions, and there's no point introducing one, when we can just make the existing 'cp' command DTRT in all cases. memmove() should at most be a few instructions more then memcpy() (to detect the appropriate direction to do the copy), which is of course completely in the noise with all the string processing that a shell command does.
Signed-off-by: Rasmus Villemoes rasmus.villemoes@prevas.dk
cmd/mem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
Reviewed-by: Simon Glass sjg@chromium.org
Is there any size growth? I assume not.
diff --git a/cmd/mem.c b/cmd/mem.c index 66c2d36a148..c696b92a274 100644 --- a/cmd/mem.c +++ b/cmd/mem.c @@ -361,7 +361,7 @@ static int do_mem_cp(struct cmd_tbl *cmdtp, int flag, int argc, } #endif
memcpy(dst, src, count * size);
memmove(dst, src, count * size); unmap_sysmem(src); unmap_sysmem(dst);-- 2.40.1.1.g1c60b9335d
Would you like to add to doc/usage/cmd/ and test/cmd as well?
Regards, Simon
participants (2)
-
Rasmus Villemoes -
Simon Glass