From: Simon Wright <simon@pushface.org>
Subject: Re: Forcing GNAT to use 32-bit load/store instructions on ARM?
Date: Fri, 11 Jul 2014 19:05:24 +0100
Date: 2014-07-11T19:05:24+01:00 [thread overview]
Message-ID: <lybnsv3h5n.fsf@pushface.org> (raw)
In-Reply-To: lpm33o$vn0$2@dont-email.me
Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP> writes:
> On 2014-07-10, Simon Wright <simon@pushface.org> wrote:
>> Simon Wright <simon@pushface.org> writes:
>>
>>> The x86_64 code accesses all 32 bits of V. If it is more efficient on
>>> arm to access the relevant bytes for the component assignments, I
>>> expect that's what would happen (as reported).
>>
>> Just tried this on Raspberry Pi (GCC 4.6.3): yes, it only accesses the
>> relevant bytes.
>
> Just to make sure: you mean it uses ldrb/strb instead of ldr/str
> in the generated code ?
Yes. I don't understand all the asm, but that part is clear!
_ada_atom:
@ args = 0, pretend = 0, frame = 0
@ frame_needed = 0, uses_anonymous_args = 0
@ link register save eliminated.
ldr r2, .L2
ldr r3, .L2+4
ldmia r2, {r1, r2}
str r1, [r3, #0]
ldrb r1, [r3, #0] @ zero_extendqisi2
bic r1, r1, #1
strb r1, [r3, #0]
ldrb r1, [r3, #3] @ zero_extendqisi2
bic r1, r1, #128
strb r1, [r3, #3]
str r2, [r3, #0]
bx lr
next prev parent reply other threads:[~2014-07-11 18:05 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-30 22:11 Forcing GNAT to use 32-bit load/store instructions on ARM? daniel.dmk
2014-06-30 23:41 ` Jeffrey Carter
2014-07-01 12:06 ` Simon Clubley
2014-07-01 15:44 ` Niklas Holsti
2014-07-01 17:26 ` Simon Clubley
2014-07-01 17:18 ` Simon Wright
2014-07-01 19:43 ` Simon Wright
2014-07-01 17:28 ` Jeffrey Carter
2014-07-01 0:55 ` anon
2014-07-01 4:30 ` Niklas Holsti
2014-07-01 8:11 ` Dmitry A. Kazakov
2014-07-01 12:09 ` Simon Clubley
2014-07-01 12:20 ` Dmitry A. Kazakov
2014-07-01 17:00 ` Simon Clubley
2014-07-01 19:36 ` Dmitry A. Kazakov
2014-07-01 20:08 ` Simon Clubley
2014-07-02 22:24 ` Randy Brukardt
2014-07-06 20:40 ` MatthiasR
2014-07-07 0:25 ` Simon Clubley
2014-07-07 22:38 ` Randy Brukardt
2014-07-08 6:51 ` Simon Wright
2014-07-10 11:47 ` Simon Wright
2014-07-10 13:06 ` Simon Clubley
2014-07-11 18:05 ` Simon Wright [this message]
2014-07-11 20:22 ` Simon Clubley
2014-07-08 8:50 ` Brian Drummond
2014-07-08 12:12 ` Simon Clubley
2014-07-08 13:26 ` G.B.
2014-07-08 17:13 ` Simon Clubley
2014-07-08 15:36 ` Adam Beneschan
2014-07-08 15:40 ` Adam Beneschan
2014-07-08 20:34 ` Randy Brukardt
2014-07-09 7:31 ` Dmitry A. Kazakov
2014-07-10 0:11 ` Simon Clubley
2014-07-20 11:35 ` MatthiasR
2014-07-20 15:49 ` Simon Clubley
2014-07-26 11:05 ` MatthiasR
2014-08-10 11:20 ` MatthiasR
2014-07-01 12:03 ` Simon Clubley
2014-07-01 19:52 ` daniel.dmk
2014-07-01 20:40 ` Simon Clubley
2014-07-01 20:55 ` Simon Clubley
2014-07-01 21:01 ` Niklas Holsti
2014-07-01 21:20 ` Simon Clubley
2014-07-01 22:38 ` Niklas Holsti
2014-07-02 16:49 ` Simon Clubley
2014-07-01 21:55 ` daniel.dmk
2014-07-02 7:30 ` Simon Wright
2014-07-02 18:52 ` daniel.dmk
2014-07-04 23:51 ` Niklas Holsti
2014-07-05 0:18 ` Niklas Holsti
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