gaumondp@JSP.UMontreal.CA (Gaumond Pierre) (04/26/91)
I would like to know the internal (binary) format of floating point numbers
(single AND double precision) on the SGI 4D/380S (MIPS R3000 processors).
- Mantissa (M) and exponent (E) positions and sizes.
- Is there any bias or offset to the exponent?
- Is F=M*2^E or F=M*16^E ?
- What are the rules on normalisation (shifting left the most significant
bit of the mantissa)?
- Are there two exponent fields in double precision?
- negative numbers.
- Negative exponent (small numbers).
- Are there some invalid representations (giving arithmetic faults when
used)?
- etc ...
I will use this information to migrate binary files containing floating point
numbers to the SGI machine mentionned above. I already know the format of the
floating point numbers on the source machine.
I want these informations to keep as much precision as possible. I don't want
to convert numbers in decimal format and translate back in binary on the SIG
because some precision is lost in these conversions.
Thanks.
Pierre Gaumond.
--
Pierre Gaumond. | gaumondp@JSP.UMontreal.CA
Services Informatiques, Universite de Montreal. | gaumondp@centrcn.UMontreal.CA
C.P. 6128, Succursale "A", Montreal, |
Quebec, Canada. H3C 3J7 |mike@BRL.MIL (Mike Muuss) (05/17/91)
The SGI 4D machines all use IEEE floating point format. I'll send Pierre some library routines for converting to/from all other binary floating point formats. Best, -Mike