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3.6.2.3 Flonums

A flonum represents a floating point number. The translation is indirect: a decimal floating point number from the text is converted by as to a generic binary floating point number of more than sufficient precision. This generic floating point number is converted to a particular computer's floating point format (or formats) by a portion of as specialized to that computer.

A flonum is written by writing (in order)

• The digit `0'. (`0' is optional on the HPPA.)

• A letter, to tell as the rest of the number is a flonum. e is recommended. Case is not important.

  On the H8/300, H8/500, Hitachi SH, and AMD 29K architectures, the letter must be one of the letters `DFPRSX' (in upper or lower case).

  On the ARC, the letter must be one of the letters `DFRS' (in upper or lower case).

  On the Intel 960 architecture, the letter must be one of the letters `DFT' (in upper or lower case).

  On the HPPA architecture, the letter must be `E' (upper case only).

• An optional sign: either `+' or `-'.

• An optional integer part: zero or more decimal digits.

• An optional fractional part: `.' followed by zero or more decimal digits.

• An optional exponent, consisting of:
  • An `E' or `e'.
  • Optional sign: either `+' or `-'.
  • One or more decimal digits.

At least one of the integer part or the fractional part must be present. The floating point number has the usual base-10 value.

as does all processing using integers. Flonums are computed independently of any floating point hardware in the computer running as.