Thread overview
How many bits in the mantissa if I declare all floats as long doubles ?
Jun 18, 2006
Nicholas Jordan
Jun 18, 2006
Walter Bright
Jun 19, 2006
Scott Michel
June 18, 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.


June 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.
June 19, 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. :-)