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Re: osf.S using 3 operand jmp and jsr
- From: Richard Henderson <rth at redhat dot com>
- To: "John E. Malmberg" <wb8tyw at qsl dot net>, libffi-discuss at sourceware dot org
- Date: Wed, 25 Feb 2015 06:40:51 -1000
- Subject: Re: osf.S using 3 operand jmp and jsr
- Authentication-results: sourceware.org; auth=none
- References: <mcki4j$ip$1 at ger dot gmane dot org>
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~