emit_rm in MacroAssembler

[Christian Thalinger]

On Mon, 2009-02-23 at 11:26 -0800, Tom Rodriguez wrote:
> They aren't structured the same at all.  I think you want something  
> like this for the 64 bit reg/reg:
> 
>    emit_byte(0xF3);
>    int encode = prefixq_and_encode(dst->encoding(), src->encoding());
>    emit_byte(0x0f);
>    emit_byte(0xb8);
>    emit_byte(0xc0 | encode);
> 
> The prefix* family of functions take care of emitting the proper REXs  
> and masking the registers down to 3 bits.  Use the regular  
> prefix_and_encode for popcntl.

That's almost exactly what I did:

+void Assembler::popcntl(Register dst, Register src) {
+  //assert(VM_Version::supports_popcnt(), "must support");
+  emit_byte(0xF3);
+  int encode = prefix_and_encode(dst->encoding(), src->encoding());
+  emit_byte(0x0F);
+  emit_byte(0xB8);
+  emit_byte(encode);
+}

But your code emits the correct instruction :-)  Shouldn't the 0xC0 part
be in some kind of function?

-- Christian