runtime/platform/arm.h

   1 #define MLton_Platform_Arch_host "arm"
   2
   3 /* Work around broken rounding mode control on ARM
   4  *
   5  * ARM CPUs can be running with either hardware or software.
   6  * Neither support rounding modes with fe{get,set}round.
   7  * Rounding direction is part of the instruction format.
   8  *
   9  * Unfortunately, due to vendor stupidity, every OS deals
  10  * with this differently:
  11  *  Some pretend to support it and ignore calls.
  12  *  Some throw an error even for the supported mode (TO_NEAREST).
  13  *  All of them define all of the TO_* macros in defiance of the standard.
  14  * ... basically, the system libraries are useless.
  15  *
  16  * The solution for MLton: replace fe{get,set}round with our own honest
  17  * versions which accept TO_NEAREST and fail for other values.
  18  */
  19
  20 #undef fegetround
  21 #undef fesetround
  22 #define fegetround MLton_fegetround
  23 #define fesetround MLton_fesetround
  24
  25 static inline int fegetround(void) {
  26   return FE_TONEAREST;
  27 }
  28
  29 static inline int fesetround(int rounding_mode) {
  30   return (rounding_mode==FE_TONEAREST)?0:1;
  31 }