[newlib-cygwin] arm: Update strcpy.c to use UAL syntax.

[newlib-cygwin] arm: Update strcpy.c to use UAL syntax.

[Corinna Vinschen]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=4bce7ecbe19c1c264e3b5b3eac9582c429f12caa

commit 4bce7ecbe19c1c264e3b5b3eac9582c429f12caa
Author: Ian Tessier via newlib <newlib@sourceware.org>
Date:   Wed Jul 19 14:02:43 2017 -0700

    arm: Update strcpy.c to use UAL syntax.
    
    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.

Diff:
---
 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 f1205b9..1544511 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"