Stop ARM setjmp/longjmp saving/restoring fpscr (bug 14908)

["Joseph S. Myers" <joseph@codesourcery.com>]

This patch fixes bug 14908, ARM setjmp/longjmp wrongly saving and
restoring fpscr.  Tested in conjunction with my libc patch
<http://sourceware.org/ml/libc-alpha/2013-05/msg00474.html> to add a
testcase for this issue; will commit once the libc testcase is in.

2013-05-14  Joseph Myers  <joseph@codesourcery.com>

	[BZ #14908]
	* sysdeps/arm/setjmp.S (__sigsetjmp): Don't save fpscr.
	* sysdeps/arm/__longjmp.S (__longjmp): Don't restore fpscr.
	* sysdeps/arm/bits/setjmp.h (__jmp_buf): Don't mention fpscr in
	comment.

diff --git a/ports/sysdeps/arm/__longjmp.S b/ports/sysdeps/arm/__longjmp.S
index 8de9fa1..a5edede 100644
--- a/ports/sysdeps/arm/__longjmp.S
+++ b/ports/sysdeps/arm/__longjmp.S
@@ -83,11 +83,6 @@ ENTRY (__longjmp)
 	/* Following instruction is vldmia ip!, {d8-d15}.  */
 	sfi_breg r12, \
 	ldc	p11, cr8, [\B], #64
-	/* Restore the floating-point status register.  */
-	sfi_breg ip, \
-	ldr     a3, [\B], #4
-	/* Following instruction is fmxr fpscr, a3.  */
-	mcr	p10, 7, a3, cr1, cr0, 0
 .Lno_vfp:
 
 #ifndef ARM_ASSUME_NO_IWMMXT
diff --git a/ports/sysdeps/arm/bits/setjmp.h b/ports/sysdeps/arm/bits/setjmp.h
index 21bbf7f..c8c3a9a 100644
--- a/ports/sysdeps/arm/bits/setjmp.h
+++ b/ports/sysdeps/arm/bits/setjmp.h
@@ -28,9 +28,9 @@
 /* The exact set of registers saved may depend on the particular core
    in use, as some coprocessor registers may need to be saved.  The C
    Library ABI requires that the buffer be 8-byte aligned, and
-   recommends that the buffer contain 64 words.  The first 28 words
-   are occupied by v1-v6, sl, fp, sp, pc, d8-d15, and fpscr.  (Note
-   that d8-15 require 17 words, due to the use of fstmx.)  */
+   recommends that the buffer contain 64 words.  The first 27 words
+   are occupied by v1-v6, sl, fp, sp, pc, and d8-d15.  (Note that
+   d8-15 require 17 words, due to the use of fstmx.)  */
 typedef int __jmp_buf[64] __attribute__((__aligned__ (8)));
 #endif
 
diff --git a/ports/sysdeps/arm/setjmp.S b/ports/sysdeps/arm/setjmp.S
index f750470..a6c161d 100644
--- a/ports/sysdeps/arm/setjmp.S
+++ b/ports/sysdeps/arm/setjmp.S
@@ -67,11 +67,6 @@ ENTRY (__sigsetjmp)
 	/* Following instruction is vstmia ip!, {d8-d15}.  */
 	sfi_breg ip, \
 	stc	p11, cr8, [\B], #64
-	/* Store the floating-point status register.  */
-	/* Following instruction is vmrs a4, fpscr.  */
-	mrc	p10, 7, a4, cr1, cr0, 0
-	sfi_breg ip, \
-	str	a4, [\B], #4
 .Lno_vfp:
 
 #ifndef ARM_ASSUME_NO_IWMMXT

-- 
Joseph S. Myers
joseph@codesourcery.com