Re: Using inline assembler

[anonymous via Digitalmars-d-learn]

On Thursday, 9 October 2014 at 12:37:20 UTC, Etienne wrote:

I'm a bit new to the inline assembler, I'm trying to use the `movdqu` operation to move a 128 bit double quadword from a pointer location into another location like this:

align(16) union __m128i { ubyte[16] data };

void store(__m128i* src, __m128i* dst) {
        asm { movdqu [dst], src; }
}

The compiler complains about a "bad type/size of operands 'movdqu'", but these two data segments are 16 byte align so they should be in an XMM# register? Is there something I'm missing here?

I know virtually nothing about SSE, but you can't move directly
from memory to memory, can you? You need go through a register,
no?

This compiles:

align(16) union __m128i { ubyte[16] data; } /* note the position
of the semicolon */

void store(__m128i* src, __m128i* dst) {
     asm
     {
         movdqu XMM0, [src]; /* note: [src] */
         movdqu [dst], XMM0;
     }
}