2006/1/13, Trenton Adams <[EMAIL PROTECTED]>: > On 1/12/06, John Myers <[EMAIL PROTECTED]> wrote: > > On Thursday 12 January 2006 18:45, Tom Smith wrote: > > > Well, if they're /not/ mutually exclusive, another question that comes > > > up is... > > > > > > If a program is compiled with sse or sse2 support on a Pentium II, will > > > the program run slower than it otherwise would? (Some of the programs I > > > have are compiled and then distributed to servers with different > > > CPUs--P-IIs and P-IVs, mainly.) > > > > > > > If a program uses an instruction that the processor doesn't support, the > > program will be sent SIGILL, the default action of which is to terminate > > immediately. > > Are you absolutely positive of that? I *thought* (would have thought) > compilers these days would compile in conditional use of such > instructions? That way if large blocks could benefit from these new > instructions, they would use them, otherwise fall back to a common set > of instructions. Of course this wouldn't be very beneficial for small > sections of code. I've been wondering about this for quite some time > though, but never bothered to investigate.
GCC does make architecture exclusive code, specially with optimed for size code. For example, code that is compiled with -march=pentium4 won't run in PIII and will give you error messages, like SIGILL or more verbose error like Invalid Instruction or something like that. > > > -- > > # > > # electronerd, the electronerdian from electronerdia > > # > > > > > > > > -- > [email protected] mailing list > > -- [email protected] mailing list
