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, Renesas / SuperH 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.

- An `

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`.