Mail Archives: djgpp/2001/02/19/09:12:40
Eli Zaretskii <eliz AT is DOT elta DOT co DOT il> wrote:
> On Sun, 18 Feb 2001, G=FCnter Reusing wrote:
>> Does anyone know a DJGPP compiler (DOS/Windows) for output of x86-64 or
>> 3D-now code?
> What's x86-64?
He probably means AMD's latest CPU development, also known as
'Sledgehammer': a new design with x86-like structure of opcodes and
registers, but everything that used to be 32 bits wide is now 64bits
wide. A repetition of the step up from 286 to 386, sort of.
> And under what circumstances would you like GCC to emit 3D-now
> instructions?
I second the implicit doubt you express here, Eli. As far as I know,
MMX and 3DNow! are really almost completely unusable for compiled
languages. Very different datatypes and access method from the CPU
and traditional FPU, and you have to save the whole FPU state before
and after, or be certain that the FPU contains no valuable
information, to be able to use these extensions. It's basically an
all-or-nothing decision: either FPU or MMX. Mixing them is hard, if
not impossible, for the compiler. But C assumes the presence of the
FPU. This effectively limits the use of these technolgies to
hand-coded, optionally inlined, assembly routines.
--
Hans-Bernhard Broeker (broeker AT physik DOT rwth-aachen DOT de)
Even if all the snow were burnt, ashes would remain.
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