+2024-04-19 Bruno Haible <bruno@clisp.org>
+
+ signed-nan: Don't assume that '-' works as expected on NaN values.
+ * lib/signed-nan.h (minus_NaNf): New function.
+ (positive_NaNf, negative_NaNf): Use it.
+ (minus_NaNd): New function.
+ (positive_NaNd, negative_NaNd): Use it.
+ (minus_NaNl): New function.
+ (positive_NaNl, negative_NaNl): Use it.
+
2024-04-18 Bruno Haible <bruno@clisp.org>
totalorder*: Support newer MIPS CPUs.
#include "nan.h"
+/* Returns - x, implemented by inverting the sign bit,
+ so that it works also on 'float' NaN values. */
+_GL_UNUSED static float
+minus_NaNf (float x)
+{
+#if defined __mips__
+ /* The mips instruction neg.s may have no effect on NaNs.
+ Therefore, invert the sign bit using integer operations. */
+ union { unsigned int i; float value; } u;
+ u.value = x;
+ u.i ^= 1U << 31;
+ return u.value;
+#else
+ return - x;
+#endif
+}
+
/* Returns a quiet 'float' NaN with sign bit == 0. */
_GL_UNUSED static float
positive_NaNf ()
/* 'volatile' works around a GCC bug:
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111655> */
float volatile nan = NaNf ();
- return (signbit (nan) ? - nan : nan);
+ return (signbit (nan) ? minus_NaNf (nan) : nan);
}
/* Returns a quiet 'float' NaN with sign bit == 1. */
/* 'volatile' works around a GCC bug:
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111655> */
float volatile nan = NaNf ();
- return (signbit (nan) ? nan : - nan);
+ return (signbit (nan) ? nan : minus_NaNf (nan));
}
+/* Returns - x, implemented by inverting the sign bit,
+ so that it works also on 'double' NaN values. */
+_GL_UNUSED static double
+minus_NaNd (double x)
+{
+#if defined __mips__
+ /* The mips instruction neg.d may have no effect on NaNs.
+ Therefore, invert the sign bit using integer operations. */
+ union { unsigned long long i; double value; } u;
+ u.value = x;
+ u.i ^= 1ULL << 63;
+ return u.value;
+#else
+ return - x;
+#endif
+}
+
/* Returns a quiet 'double' NaN with sign bit == 0. */
_GL_UNUSED static double
positive_NaNd ()
/* 'volatile' works around a GCC bug:
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111655> */
double volatile nan = NaNd ();
- return (signbit (nan) ? - nan : nan);
+ return (signbit (nan) ? minus_NaNd (nan) : nan);
}
/* Returns a quiet 'double' NaN with sign bit == 1. */
/* 'volatile' works around a GCC bug:
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111655> */
double volatile nan = NaNd ();
- return (signbit (nan) ? nan : - nan);
+ return (signbit (nan) ? nan : minus_NaNd (nan));
}
+/* Returns - x, implemented by inverting the sign bit,
+ so that it works also on 'long double' NaN values. */
+_GL_UNUSED static long double
+minus_NaNl (long double x)
+{
+ return - x;
+}
+
/* Returns a quiet 'long double' NaN with sign bit == 0. */
_GL_UNUSED static long double
positive_NaNl ()
/* 'volatile' works around a GCC bug:
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111655> */
long double volatile nan = NaNl ();
- return (signbit (nan) ? - nan : nan);
+ return (signbit (nan) ? minus_NaNl (nan) : nan);
}
/* Returns a quiet 'long double' NaN with sign bit == 1. */
/* 'volatile' works around a GCC bug:
<https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111655> */
long double volatile nan = NaNl ();
- return (signbit (nan) ? nan : - nan);
+ return (signbit (nan) ? nan : minus_NaNl (nan));
}