Floating Point Formats

	IEEE 4 byte real

	31 30	 23 22			      0
	|-------------------------------------.
	|s| 8 bits |msb   23 bit mantissa  lsb|
	`-------------------------------------'
	 |	|		 `----------------  mantissa
	 |	`--------------------------------  biased exponent (7fh)
	 `-------------------------------------  sign bit

	IEEE 8 byte real

	63 62	   52 51				  0
	|-------------------------------------------------.
	|s|  11 bits |msb	 52 bit mantissa       lsb|
	`-------------------------------------------------'
	 |	|		 `----------------  mantissa
	 |	`--------------------------------  biased exponent (3FFh)
	 `-------------------------------------  sign bit

	Microsoft 4 byte real

	31     24 23 22			      0
	|-------------------------------------.
	| 8 bits |s|msb  23 bit mantissa   lsb|
	`-------------------------------------'
	     |	  |		 `----------------  mantissa
	     |	  `----------------------------  sign bit
	     `------------------------------  biased exponent (81h)

	Microsoft 8 byte real (see note below)

	63    56 55 54 				       0
	|----------------------------------------------.
	| 8bits |s|msb		52 bit mantissa	    lsb|
	`----------------------------------------------'
	    |	 |		      `------------  mantissa
	    |	 `-----------------------------  sign bit
	    `---------------------------  biased exponent (401h, see below)

	IEEE 10 byte real (temporary real)

	79 78	    64 63 62					 0
	|--------------------------------------------------------.
	|s|  15 bits  |1|msb	      63 bit mantissa	      lsb|
	`--------------------------------------------------------'
	 |	|      |		    `-----  mantissa
	 |	|      `------------------------  first mantissa bit
	 |	`-----------------------------	biased exponent (3FFFh)
	 `----------------------------------  sign bit

	Turbo Pascal 6 byte real

	47     40 39 38					0
	|-----------------------------------------------.
	| 8 bits |s|msb		39 bit mantissa	     lsb|
	`-----------------------------------------------'
	     |	  |		     `------------  mantissa
	     |	  `-----------------------------  sign bit
	     `--------------------------------  biased exponent (80h)

	Microsoft Fortran Complex number
	|--------------------------------------------------------.
	|   Float Real component   |  Float Imaginary component  |
	`--------------------------------------------------------'
	(each component is either 8 or 16 byte IEEE real)


	- sign bit representation:  0 is positive  and	1 is negative
	- in all float formats except the IEEE 10 byte real, the
	  mantissa is stored without most significant bit; since
	  the state of this bit is known to be set, it is not
	  included and the exponent is adjusted accordingly
	- all formats use binary float representation
	- memory representation uses 80x86 reverse byte/word order.
	- Microsoft languages use the IEEE real formats;  BASIC is the
	  only normal user of the Microsoft float format
	- Microsoft 8 byte real format has not been verified;  several
	  Microsoft publications show an 8 bit exponent instead of 11 bits
	  and state the BIAS is 401h;  the discrepancy is that 8 bits can't
	  hold the value 401h (requires 11 bits)


	True exponent is the exponent value minus the following bias:

	81h for Microsoft 4 byte real
	401h for Microsoft 8 byte real
	7Fh for IEEE 4 byte real
	3FFh for IEEE 8 byte real
	80h for Turbo Pascal 6 byte real

	     Size		   Range	     Significant digits

	4 byte real	  8.43x10E-37 to 3.37x10E38	    6-7
	8 byte real	 4.19x10E-307 to 1.67x10E308	   15-16
	10 byte real	 3.4x10E-4932 to 1.2x10E4932	     19


	- see	dmsbintoieee()   dieeetomsbin()   NUMERIC RANGES