[PATCH] sparc: Prevent stfsr from directly following floating-point instruction

[Daniel Cederman <cederman@gaisler.com>]

On LEON, if the stfsr instruction is immediately following a floating-point
operation instruction in a running program, with no other instruction in
between the two, the stfsr might behave as if the order was reversed
between the two instructions and the stfsr occurred before the
floating-point operation.

Add a nop instruction before the stfsr to prevent this from happening.

Signed-off-by: Daniel Cederman <cederman@gaisler.com>
---
 sysdeps/sparc/fpu/fenv_private.h | 6 +++++-
 sysdeps/sparc/fpu/fpu_control.h  | 6 +++++-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/sysdeps/sparc/fpu/fenv_private.h b/sysdeps/sparc/fpu/fenv_private.h
index da7c7fe332..a02af80d04 100644
--- a/sysdeps/sparc/fpu/fenv_private.h
+++ b/sysdeps/sparc/fpu/fenv_private.h
@@ -8,7 +8,11 @@
 # define __fenv_stfsr(X)   __asm__ __volatile__ ("stx %%fsr,%0" : "=m" (X))
 # define __fenv_ldfsr(X)   __asm__ __volatile__ ("ldx %0,%%fsr" : : "m" (X))
 #else
-# define __fenv_stfsr(X)   __asm__ __volatile__ ("st %%fsr,%0" : "=m" (X))
+# ifdef __leon__
+#  define __fenv_stfsr(X)   __asm__ __volatile__ ("nop; st %%fsr,%0" : "=m" (X))
+# else
+#  define __fenv_stfsr(X)   __asm__ __volatile__ ("st %%fsr,%0" : "=m" (X))
+# endif
 # define __fenv_ldfsr(X)   __asm__ __volatile__ ("ld %0,%%fsr" : : "m" (X))
 #endif
 
diff --git a/sysdeps/sparc/fpu/fpu_control.h b/sysdeps/sparc/fpu/fpu_control.h
index dd18789573..9313743f86 100644
--- a/sysdeps/sparc/fpu/fpu_control.h
+++ b/sysdeps/sparc/fpu/fpu_control.h
@@ -61,7 +61,11 @@ typedef unsigned long int fpu_control_t;
 # define _FPU_GETCW(cw) __asm__ __volatile__ ("stx %%fsr,%0" : "=m" (*&cw))
 # define _FPU_SETCW(cw) __asm__ __volatile__ ("ldx %0,%%fsr" : : "m" (*&cw))
 #else
-# define _FPU_GETCW(cw) __asm__ __volatile__ ("st %%fsr,%0" : "=m" (*&cw))
+# ifdef __leon__
+#  define _FPU_GETCW(cw) __asm__ __volatile__ ("nop; st %%fsr,%0" : "=m" (*&cw))
+# else
+#  define _FPU_GETCW(cw) __asm__ __volatile__ ("st %%fsr,%0" : "=m" (*&cw))
+# endif
 # define _FPU_SETCW(cw) __asm__ __volatile__ ("ld %0,%%fsr" : : "m" (*&cw))
 #endif
 
-- 
2.40.1