From: Scott Wood
Sent: 26 May 2015 20:43
...
I was thinking of all 64bit targets, not 32bit ones.
Oh, you mean move it out of arch/powerpc? Sounds reasonable, but
someone should probably check what the resulting code looks like on
other common arches. OTOH, if we're going to modify
From: Scott Wood ...
I'd also have thought that the 64bit C version above would be generally
'good'.
It doesn't generate the addc/addze sequence. At least with GCC 4.8.2,
it does something like:
mr tmp0, csum
li tmp1, 0
li tmp2, 0
addc
On Tue, 2015-05-26 at 13:57 +, David Laight wrote:
From: Scott Wood ...
I'd also have thought that the 64bit C version above would be
generally 'good'.
It doesn't generate the addc/addze sequence. At least with GCC
4.8.2,
it does something like:
mr tmp0, csum
On Fri, 2015-05-22 at 16:39 -0500, Segher Boessenkool wrote:
On Fri, May 22, 2015 at 02:32:42PM -0500, Scott Wood wrote:
I'd also have thought that the 64bit C version above would be generally
'good'.
It doesn't generate the addc/addze sequence. At least with GCC 4.8.2,
it does
On Fri, May 22, 2015 at 02:32:42PM -0500, Scott Wood wrote:
I'd also have thought that the 64bit C version above would be generally
'good'.
It doesn't generate the addc/addze sequence. At least with GCC 4.8.2,
it does something like:
mr tmp0, csum
li tmp1, 0
From: Linuxppc-dev Christophe Leroy
Sent: 19 May 2015 16:19
...
diff --git a/arch/powerpc/include/asm/checksum.h
b/arch/powerpc/include/asm/checksum.h
index 5e43d2d..e8d9ef4 100644
--- a/arch/powerpc/include/asm/checksum.h
+++ b/arch/powerpc/include/asm/checksum.h
@@ -130,6 +130,22 @@
On Fri, 2015-05-22 at 15:57 +, David Laight wrote:
From: Linuxppc-dev Christophe Leroy
Sent: 19 May 2015 16:19
...
diff --git a/arch/powerpc/include/asm/checksum.h
b/arch/powerpc/include/asm/checksum.h
index 5e43d2d..e8d9ef4 100644
--- a/arch/powerpc/include/asm/checksum.h
+++
The C version of csum_add() as defined in include/net/checksum.h gives the
following assembly in ppc32:
0: 7c 04 1a 14 add r0,r4,r3
4: 7c 64 00 10 subfc r3,r4,r0
8: 7c 63 19 10 subfe r3,r3,r3
c: 7c 63 00 50 subf
