## c++ - How many bits in the mantissa if I declare all floats as long doubles ?

- Nicholas Jordan <Nicholas_member pathlink.com> Jun 18 2006
- Walter Bright <newshound digitalmars.com> Jun 18 2006
- Scott Michel <scottm aero.org> Jun 19 2006

The source code for an entrophy testing method I am trying to incorporate in my program has the comment: /* Bytes used as Monte Carlo co-ordinates. This should be no more bits than the mantissa of your "double" floating point type. */ #define MONTEN 6 I cannot determine from either the .asm or the .h or the help files how many bits are in the mantissa.

Jun 18 2006

Nicholas Jordan wrote:The source code for an entrophy testing method I am trying to incorporate in my program has the comment: /* Bytes used as Monte Carlo co-ordinates. This should be no more bits than the mantissa of your "double" floating point type. */ #define MONTEN 6 I cannot determine from either the .asm or the .h or the help files how many bits are in the mantissa.

long doubles have a 64 bit mantissa, a 15 bit exponent, and a 1 bit sign.

Jun 18 2006

Walter Bright wrote:Nicholas Jordan wrote:The source code for an entrophy testing method I am trying to incorporate in my program has the comment: /* Bytes used as Monte Carlo co-ordinates. This should be no more bits than the mantissa of your "double" floating point type. */ #define MONTEN 6 I cannot determine from either the .asm or the .h or the help files how many bits are in the mantissa.

long doubles have a 64 bit mantissa, a 15 bit exponent, and a 1 bit sign.

I'd really like to see a SEF float format with two or more sign bits. :-)

Jun 19 2006