From: Corinna Vinschen <vinschen@redhat.com>
To: newlib@sourceware.org
Subject: Re: [PATCH] arm: Update strcpy.c to use UAL syntax.
Date: Thu, 20 Jul 2017 14:19:00 -0000 [thread overview]
Message-ID: <20170720141942.GC19395@calimero.vinschen.de> (raw)
In-Reply-To: <20170719210243.8975-1-itessier@google.com>
[-- Attachment #1: Type: text/plain, Size: 2380 bytes --]
On Jul 19 14:02, Ian Tessier via newlib wrote:
> With this change the arm platform can now be fully compiled with Clang.
>
> Tested by comparing the output with GCC 4.8.2, and Clang 4.0, using a
> variety of arches, big/little endianness, and arm/thumb mode to verify
> the generated assembly output matches between GCC vs Clang with UAL, and
> also GCC with UAL vs GCC with non-UAL, for all preprocessor code blocks.
>
> The only difference found is an extra nop at the end of the function
> when compiled with GCC using armv7-a/thumb/little-endian/-O2 compared to
> Clang. The nop is not emitted when compiled in big-endian mode.
> ---
> newlib/libc/machine/arm/strcpy.c | 13 +++++++------
> 1 file changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/newlib/libc/machine/arm/strcpy.c b/newlib/libc/machine/arm/strcpy.c
> index f1205b9c1..154451110 100644
> --- a/newlib/libc/machine/arm/strcpy.c
> +++ b/newlib/libc/machine/arm/strcpy.c
> @@ -42,6 +42,7 @@ char* __attribute__((naked))
> strcpy (char* dst, const char* src)
> {
> asm (
> + ".syntax unified\n\t"
> #if !(defined(__OPTIMIZE_SIZE__) || defined (PREFER_SIZE_OVER_SPEED) || \
> (defined (__thumb__) && !defined (__thumb2__)))
> #ifdef _ISA_ARM_7
> @@ -127,15 +128,15 @@ strcpy (char* dst, const char* src)
> #ifdef __ARMEB__
> "tst r2, #0xff00\n\t"
> "iteet ne\n\t"
> - "strneh r2, [ip], #2\n\t"
> + "strhne r2, [ip], #2\n\t"
> "lsreq r2, r2, #8\n\t"
> - "streqb r2, [ip]\n\t"
> + "strbeq r2, [ip]\n\t"
> "tstne r2, #0xff\n\t"
> #else
> "tst r2, #0xff\n\t"
> "itet ne\n\t"
> - "strneh r2, [ip], #2\n\t"
> - "streqb r2, [ip]\n\t"
> + "strhne r2, [ip], #2\n\t"
> + "strbeq r2, [ip]\n\t"
> "tstne r2, #0xff00\n\t"
> #endif
> "bne 5b\n\t"
> @@ -162,9 +163,9 @@ strcpy (char* dst, const char* src)
> "mov r3, r0\n\t"
> "1:\n\t"
> "ldrb r2, [r1]\n\t"
> - "add r1, r1, #1\n\t"
> + "adds r1, #1\n\t"
> "strb r2, [r3]\n\t"
> - "add r3, r3, #1\n\t"
> + "adds r3, #1\n\t"
> "cmp r2, #0\n\t"
> "bne 1b\n\t"
> "bx lr\n\t"
> --
> 2.14.0.rc0.284.gd933b75aa4-goog
Pushed.
Thanks,
Corinna
--
Corinna Vinschen
Cygwin Maintainer
Red Hat
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 819 bytes --]
next prev parent reply other threads:[~2017-07-20 14:19 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-19 21:02 Ian Tessier via newlib
2017-07-20 14:19 ` Corinna Vinschen [this message]
2017-07-21 10:21 ` Richard Earnshaw (lists)
[not found] ` <CAP235ST1nYzhCDsyzE7A6NXjP2hg_sy=4bjzD_3OCXQerLYmnA@mail.gmail.com>
2017-07-21 21:13 ` Ian Tessier via newlib
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20170720141942.GC19395@calimero.vinschen.de \
--to=vinschen@redhat.com \
--cc=newlib@sourceware.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).