On Saturday, 19 January 2013 at 12:45:06 UTC, deed wrote:
void main()
{
asm
{
mov RAX, 3;
}
}
results in:
Error: undefined identifier 'RAX'
AX and EAX work.
Anything missing or isn't it yet implemented?
Hmm. I know there's a one byte 'escape code' that for x86 allows
you to force it to a higher/lower level, perhaps that was just
the 16/32 bit code and won't work for 64bit (different escape
code?). I think it was 0x66, so you might get away 'db'
prepending that, but I wouldn't rely on it. Sides there's lots of
little intricacies of the instruction set; like you could have a
one byte assignment to any register; That's assuming they aren't
taking them away in the 64bit versions of x86.
So...
asm
{
db 66h;
mov EAX, 3; //may work, likely 1 byte assignment
db 66h;
mov EAX, 300; //4 byte assignment from 32bit register
//4 byte padding needed for 64bit.
//Little endian would allow this to work
db 0,0,0,0;
}
But that's mostly informational, refer to the technical manual
from Intel before attempting.
Hmmm I wonder, with the 64 bit systems, do they still use the
segment registers (CS, DS, SS)? I can see it being used for
telling apart virtual memory and code/data, but not for hardly
anything else; Plus it's original use has long since been
unneeded.
