tests for fenv.h, improv

code/fenv.c

@@ -4,6 +4,7 @@
 
 #define fe_masks(excepts) (((fexcept_t)(excepts)) << 7)
 #define fe_flags(excepts) ((fexcept_t)(excepts))
+#define fe_excepts(masks) ((int)(masks >> 7))
 
 fenv_t _fe_dfl_env = 0x1f80; // Based (on my machine)
 
@@ -16,7 +17,7 @@ int feclearexcept(int excepts)
         return 0;
     }
     fexcept_t csr = _mm_getcsr();
-    csr |= fe_masks(excepts);
+    csr &= ~fe_flags(excepts);
     _mm_setcsr(csr);
     return 0;
 }

inc/fenv.h

@@ -9,12 +9,18 @@ typedef unsigned fenv_t;
 #define FE_OVERFLOW  (1 << 3)
 #define FE_UNDERFLOW (1 << 4)
 #define FE_INEXACT   (1 << 5)
+// Implementation-defined flags
+#define FE_DENORM    (1 << 1)
+#define FE_DAZ       (1 << 6)
+
 #define FE_ALL_EXCEPT   \
     ( FE_INVALID        \
     | FE_DIVBYZERO      \
     | FE_OVERFLOW       \
     | FE_UNDERFLOW      \
-    | FE_INEXACT        )
+    | FE_INEXACT        \
+    | FE_DENORM         \
+    | FE_DAZ            )
 
 #define FE_TONEAREST  0x00
 #define FE_DOWNWARD   0x01

test/test6.c

@@ -1,6 +1,7 @@
 #include <stdio.h>
 #include <math.h>
 #include <fenv.h>
+#include <float.h>
 
 #include <emmintrin.h>
 
@@ -10,6 +11,18 @@ static inline double rint (double const x) {
     return (double)_mm_cvtsd_si32(_mm_load_sd(&x));
 }
 
+void show_fe_exceptions(void)
+{
+    printf("current exceptions raised: ");
+    if(fetestexcept(FE_DIVBYZERO))     printf(" FE_DIVBYZERO");
+    if(fetestexcept(FE_INEXACT))       printf(" FE_INEXACT");
+    if(fetestexcept(FE_INVALID))       printf(" FE_INVALID");
+    if(fetestexcept(FE_OVERFLOW))      printf(" FE_OVERFLOW");
+    if(fetestexcept(FE_UNDERFLOW))     printf(" FE_UNDERFLOW");
+    if(fetestexcept(FE_ALL_EXCEPT)==0) printf(" none");
+    printf("\n");
+}
+
 void show_fe_current_rounding_direction(void)
 {
     printf("current rounding direction:  ");
@@ -23,8 +36,29 @@ void show_fe_current_rounding_direction(void)
     printf("\n");
 }
 
+double x2 (double x)   /* times two */
+{
+    fenv_t curr_excepts;
+ 
+    /* Save and clear current f-p environment. */
+    feholdexcept(&curr_excepts);
+ 
+    /* Raise inexact and overflow exceptions. */
+    printf("In x2():  x = %f\n", x=x*2.0);
+    show_fe_exceptions();
+    feclearexcept(FE_INEXACT);   /* hide inexact exception from caller */
+ 
+    /* Merge caller's exceptions (FE_INVALID)        */
+    /* with remaining x2's exceptions (FE_OVERFLOW). */
+    feupdateenv(&curr_excepts);
+    return x;
+}
+
+
 int main(void)
 {
+    // ROUNDING MODES
+    printf("\nROUNDING MODES\n");
     /* Default rounding direction */
     show_fe_current_rounding_direction();
     printf("+11.5 -> %f\n", rint(+11.5)); /* midway between two integers */
@@ -43,5 +77,25 @@ int main(void)
     fesetround(curr_direction);
     show_fe_current_rounding_direction(); 
 
+    // EXCEPTION TEST
+    printf("\nEXCEPTIONS\n");
+
+    show_fe_exceptions();
+
+    /* Perform some computations which raise exceptions. */
+    printf("1.0/0.0     = %f\n", 1.0/0.0);        /* FE_DIVBYZERO            */
+    printf("1.0/10.0    = %f\n", 1.0/10.0);       /* FE_INEXACT              */
+    printf("DBL_MAX*2.0 = %f\n", DBL_MAX*2.0);    /* FE_INEXACT FE_OVERFLOW  */
+    show_fe_exceptions();
+
+    // FEHOLDEXCEPT
+    printf("\nFEHOLDEXCEPT\n");
+
+    feclearexcept(FE_ALL_EXCEPT);
+    feraiseexcept(FE_INVALID);   /* some computation with invalid argument */
+    show_fe_exceptions();
+    printf("x2(DBL_MAX) = %f\n", x2(DBL_MAX));
+    show_fe_exceptions();
+
     return 0;
 }