format: Check for NaN when rendering doubles

- The result of 0.0/0.0 was being rendered as a lot of
  zeroes in the integer portion, as in this example:

  DBGvpp# show physmem
  0: 16 objects, 576k of 582k used, 3k free, 0 reclaimed, 2k overhead,
  16380k capacity
       alloc. from small object cache: 0 hits 0 attempts (0.00%) replacements 0
       alloc. from free-list: 0 attempts, 0 hits (0.00%), 0 considered (per-attempt 0.00)
       alloc. from vector-expand: 16
       allocs: 16 73643.06 clocks/call
       frees: 0 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000.00 clocks/call

- Add two macros to vppinfra/math.h that use compiler builtins to check
  for NaN and Infinity and then use them in format_float().

Change-Id: Iccc03997e6e33d6b888d1e7e20cd78df0cfd02e8
Signed-off-by: Chris Luke <chrisy@flirble.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/src/vppinfra/math.h b/src/vppinfra/math.h
index 48f8c0f4b83..cafa1cb3d3f 100644
--- a/src/vppinfra/math.h
+++ b/src/vppinfra/math.h
@@ -52,6 +52,14 @@ fabs (f64 x)
   return __builtin_fabs (x);
 }
 
+#ifndef isnan
+#define isnan(x) __builtin_isnan(x)
+#endif
+
+#ifndef isinf
+#define isinf(x) __builtin_isinf(x)
+#endif
+
 #endif /* included_math_h */
 
 /*