[openbeos] Re: app_server: MMX/SSE help wanted
- From: "Scott Donaldson" <a_nqe@xxxxxxxxxxx>
- To: openbeos@xxxxxxxxxxxxx
- Date: Tue, 10 Aug 2004 18:20:59 +0100
AMD's code optimizing manual describes how to allocate memory aligned.
double *p;
double *np;
p = (double *)malloc(sizeof(double) * number_of_doubles + 7L);
np = (double *)((((long)(p)) + 7L) & (-8L));
Can someone clear something up for me with SSE. PADDUSB on XMM will affect
all 128b, so why does the instruction need SSE2 support according to the AMD
x86-64 manual?
I do recall there is a difference in AMD's SSE and Intel's, I can't find it
again but I recall stumbling across it a while back when I was writting a
benchmarking program. It was something like 3DNow! Pro allowed operation on
all 128b of the XMM regs using MMX instructions where as Intel's SSE
required the appropriate SSE instruction to use the whole 128b otherwise it
would only work on the lower 64b.
I might be remembering incorrectly but its been bugging me that I can't
remember where the difference is.
Am I also right in assuming that pthreads are the most suitable for cross
platform coding for BSD, Solaris, Linux, and BeOS.
bye
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