Replace lb with lbu to avoid unnecessary sign extension.
Reviewed-by: Christian Herber <christian.herber@oss.nxp.com>
Signed-off-by: m fally <marlene.fally@gmail.com>
---
newlib/libc/machine/riscv/memmove.S | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
@@ -20,15 +20,15 @@ memmove:
li a3, 1
bgtu a1, a0, .Lcopy /* in case of source address > destination address, copy from start to end of the specified memory area */
- li a3, -1 /* otherwhise, we need to start copying from the end of the specified memory area, therefore after each copied byte, increment the addresses by -1 */
- add a4, a4, a2 /* add the number of bytes to be copied to both addresses. this gives an incorrect address, */
+ li a3, -1 /* otherwhise, start copying from the end of the specified memory area in order to prevent data loss in case of overlapping memory areas.*/
+ add a4, a4, a2 /* add the number of bytes to be copied to both addresses. this gives us the address one byte past the end of the memory area we want to copy, */
add a1, a1, a2 /* therefore we need to subtract 1 from both addresses in the next step before starting the copying process. */
.Lincrement:
add a4, a4, a3 /* in case of source address < destination address, increment both addresses by -1 before copying any data to obtain the correct start addresses */
add a1, a1, a3
.Lcopy:
- lb a5, 0(a1) /* copy bytes as long as a2 (= the number of bytes to be copied) > 0 */
+ lbu a5, 0(a1) /* copy bytes as long as a2 (= the number of bytes to be copied) > 0 */
sb a5, 0(a4)
add a2, a2, -1
bnez a2, .Lincrement