(limb2dbl): New macro for conversion to `double'.

Define it to something non-trivial for 64-bit hppa.

1 files changed, 16 insertions, 2 deletions

diff --git a/mpf/get_d.c b/mpf/get_d.c
index bb5d6f98f..b5aac18d8 100644
--- a/mpf/get_d.c
+++ b/mpf/get_d.c
@@ -22,6 +22,20 @@ MA 02111-1307, USA. */
 #include "gmp.h"
 #include "gmp-impl.h"
 
+/* HPPA 8000, 8200, 8500, and 8600 traps FCNV,UDW,DBL for values >= 2^63.  This
+   makes it slow.  Worse, the Linux kernel apparently uses untested code in its
+   trap handling routines, and gets the sign wrong.  Their compiler port
+   doesn't define __hppa as it should.  Here is a workaround:  */
+#if (defined (__hppa) || defined (__hppa__)) && GMP_LIMB_BITS == 64
+#define limb2dbl(limb) \
+    ((limb) >> (GMP_LIMB_BITS - 1) != 0  				\
+     ? 2.0 * (double) (mp_limb_signed_t) (((limb) >> 1) | ((limb) & 1))	\
+     : (double) (mp_limb_signed_t) (limb))
+#else
+#define limb2dbl(limb) \
+    (double) (limb)
+#endif
+
 double
 mpf_get_d (mpf_srcptr src)
 {
@@ -38,10 +52,10 @@ mpf_get_d (mpf_srcptr src)
   size = ABS (size);
   qp = PTR(src);
 
-  res = qp[size - 1];
+  res = limb2dbl (qp[size - 1]);
   n_limbs_to_use = MIN (LIMBS_PER_DOUBLE, size);
   for (i = 2; i <= n_limbs_to_use; i++)
-    res = res * MP_BASE_AS_DOUBLE + qp[size - i];
+    res = res * MP_BASE_AS_DOUBLE + limb2dbl (qp[size - i]);
 
   res = __gmp_scale2 (res, (EXP(src) - n_limbs_to_use) * GMP_NUMB_BITS);