Minor changes to sysdeps/ieee754/dbl-64/s_fma.c

Hi @ll,

I propose the following minor changes to sysdeps/ieee754/dbl-64/s_fma.c:

1. replace

-  if ((u & 0x10000000) == 0
-     && ((u >> MANTISSA_WIDTH) & 0x7ff) > EXPONENT_BIAS - 126)

   with

+#define DOUBLE_EXPONENT_MASK (DOUBLE_EXPONENT_BIAS * 2 + 1)
+
+  if ((u & (1u << DOUBLE_MANTISSA_WIDTH - FLOAT_MANTISSA_WIDTH - 1)) == 0
+      && ((u >> DOUBLE_MANTISSA_WIDTH) & DOUBLE_EXPONENT_MASK) > DOUBLE_EXPONENT_BIAS - FLOAT_EXPONENT_BIAS)

   to better show where 0x10000000, 0x7ff and 126 originate from.

2. correct the spelling of 'double-rouding'

3. replace

-int neg = u >> 63;

   with

+int neg = (int64_t) u < 0;

4. replace

-  if (neg == (err < 0))
-    u++;
-  else
-    u--;

   with

+  u += (neg == (err < 0)) * 2 - 1;


Stefan Kanthak