Re: Inline asm constraint help

[Jason Thorpe <thorpej%me.com@localhost>]

> On Jan 31, 2019, at 7:54 AM, Jason Thorpe <thorpej%me.com@localhost> wrote:
> 
> No, I mean wN (32-bit) vs xN (64-bit) names of the general purpose registers.  Specifically, I want to use ldxr and stxr to operate on “int *” memory locations.  I know the syntax, just can’t get GCC to emit it :-/
> 
> (Sorry, I just don’t have the GCC source handy right now... and it’s online docs don’t even mention the “x” modifier as far as I can tell, but I observed its behavior.)

To follow-up, I figured it out.

	ldxr	%0,%2

resulted in:

	ldxr	x2,[x0]

...and:

	ldxr	%w0,%2

...did what I want:

	ldxr	w2,[x0]


I had assumed I needed to use a constraint modifier, but I was obviously wrong :-)

-- thorpej