* osf.S using 3 operand jmp and jsr
@ 2015-02-25 13:19 John E. Malmberg
2015-02-25 16:41 ` Richard Henderson
0 siblings, 1 reply; 2+ messages in thread
From: John E. Malmberg @ 2015-02-25 13:19 UTC (permalink / raw)
To: libffi-discuss
I noticed that the src/alpha/osf.S is using 3 operand jmp and jsr
instructions.
What does gas do with the third operand?
The VMS Macro 64 assembler only supports 2 operand jmp/jsr instructions.
Regards,
-John
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: osf.S using 3 operand jmp and jsr
2015-02-25 13:19 osf.S using 3 operand jmp and jsr John E. Malmberg
@ 2015-02-25 16:41 ` Richard Henderson
0 siblings, 0 replies; 2+ messages in thread
From: Richard Henderson @ 2015-02-25 16:41 UTC (permalink / raw)
To: John E. Malmberg, libffi-discuss
On 02/25/2015 03:18 AM, John E. Malmberg wrote:
> I noticed that the src/alpha/osf.S is using 3 operand jmp and jsr instructions.
>
> What does gas do with the third operand?
It encodes it in bits 0:13 as a branch prediction hint.
> The VMS Macro 64 assembler only supports 2 operand jmp/jsr instructions.
Since it's a hint, you can just drop it.
r~
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