--- Comment #11 from joakim dot tjernlund at transmode dot se 2010-05-21
06:23 ---
(In reply to comment #10)
On my mpc8321 it is a big difference(don't have numbers handy). Why would
such a simply insn be a problem performance wise?
I know the kernel still uses the carry insn's
--- Comment #7 from joakim dot tjernlund at transmode dot se 2010-05-20
12:13 ---
The below code doesn't generate any add with carry insn's for
either x86 nor powerpc:
u16
ipsum(u16 *buf, unsigned len, u16 sum)
{
int rest, carry ;
u32 acc_sum, *buf_u32, x;
acc_sum = sum;
len
--- Comment #8 from dje at gcc dot gnu dot org 2010-05-20 14:25 ---
Has anyone tested if generating an instruction sequence that uses the carry bit
actually improves performance on modern POWER processors? It reduces the
number of instructions, which is good when optimizing for size,
--- Comment #9 from joakim dot tjernlund at transmode dot se 2010-05-20
14:47 ---
(In reply to comment #8)
Has anyone tested if generating an instruction sequence that uses the carry
bit
actually improves performance on modern POWER processors? It reduces the
number of
--- Comment #10 from dje at gcc dot gnu dot org 2010-05-21 00:28 ---
On my mpc8321 it is a big difference(don't have numbers handy). Why would
such a simply insn be a problem performance wise?
I know the kernel still uses the carry insn's for calculating the
Internet checksum.
