Import Tcl 8.6.10

libtommath/bn_mp_set_double.c

@@ -0,0 +1,47 @@
+#include "tommath_private.h"
+#ifdef BN_MP_SET_DOUBLE_C
+/* LibTomMath, multiple-precision integer library -- Tom St Denis */
+/* SPDX-License-Identifier: Unlicense */
+
+#if defined(__STDC_IEC_559__) || defined(__GCC_IEC_559)
+mp_err mp_set_double(mp_int *a, double b)
+{
+   uint64_t frac;
+   int exp;
+   mp_err err;
+   union {
+      double   dbl;
+      uint64_t bits;
+   } cast;
+   cast.dbl = b;
+
+   exp = (int)((unsigned)(cast.bits >> 52) & 0x7FFu);
+   frac = (cast.bits & ((1uLL << 52) - 1uLL)) | (1uLL << 52);
+
+   if (exp == 0x7FF) { /* +-inf, NaN */
+      return MP_VAL;
+   }
+   exp -= 1023 + 52;
+
+   mp_set_u64(a, frac);
+
+   err = (exp < 0) ? mp_div_2d(a, -exp, a, NULL) : mp_mul_2d(a, exp, a);
+   if (err != MP_OKAY) {
+      return err;
+   }
+
+   if (((cast.bits >> 63) != 0uLL) && !MP_IS_ZERO(a)) {
+      a->sign = MP_NEG;
+   }
+
+   return MP_OKAY;
+}
+#else
+/* pragma message() not supported by several compilers (in mostly older but still used versions) */
+#  ifdef _MSC_VER
+#    pragma message("mp_set_double implementation is only available on platforms with IEEE754 floating point format")
+#  else
+#    warning "mp_set_double implementation is only available on platforms with IEEE754 floating point format"
+#  endif
+#endif
+#endif