diff options
| author | Michael Sevakis <jethead71@rockbox.org> | 2014-08-06 04:26:52 -0400 |
|---|---|---|
| committer | Michael Sevakis <jethead71@rockbox.org> | 2014-08-29 22:06:57 -0400 |
| commit | 77b3625763ae4d5aa6aaa9d44fbc1bfec6b29335 (patch) | |
| tree | 74b12e2669da8653932f48f1ca3816eef4bf6324 /firmware/asm/sh/memcpy.S | |
| parent | 7d1a47cf13726c95ac46027156cc12dd9da5b855 (diff) | |
Add mempcpy implementation
A GNU extension that returns dst + size instead of dst. It's a nice
shortcut when copying strings with a known size or back-to-back blocks
and you have to do it often.
May of course be called directly or alternately through
__builtin_mempcpy in some compiler versions.
For ASM on native targets, it is implemented as an alternate entrypoint
to memcpy which adds minimal code and overhead.
Change-Id: I4cbb3483f6df3c1007247fe0a95fd7078737462b
Diffstat (limited to 'firmware/asm/sh/memcpy.S')
| -rw-r--r-- | firmware/asm/sh/memcpy.S | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/firmware/asm/sh/memcpy.S b/firmware/asm/sh/memcpy.S index 59c5801ac0..3d623c48cd 100644 --- a/firmware/asm/sh/memcpy.S +++ b/firmware/asm/sh/memcpy.S @@ -24,8 +24,10 @@ .align 2 .global _memcpy + .global _mempcpy .global ___memcpy_fwd_entry .type _memcpy,@function + .type _mempcpy,@function /* Copies <length> bytes of data in memory from <source> to <dest> * This version is optimized for speed @@ -51,6 +53,10 @@ * The instruction order is devised in a way to utilize the pipelining * of the SH1 to the max. The routine also tries to utilize fast page mode. */ +_mempcpy: + mov r4,r7 /* store dest + length for returning */ + bra ___memcpy_fwd_entry + add r6,r7 _memcpy: mov r4,r7 /* store dest for returning */ @@ -217,3 +223,5 @@ ___memcpy_fwd_entry: mov r7,r0 /* return dest start address */ .end: .size _memcpy,.end-_memcpy + .size _mempcpy,.end-_mempcpy + |