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CPM OPERATING SYSTEMS/CPM 68K/1.0X SOURCES/v102a/doc/misc/float.doc

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+        float - floating point number formats
+             Regulus supports two formats of single  precision  floating
+        point  numbers.  They are the Motorola 'Fast Floating Point' and
+        the 'IEEE standard'.  Both types are stored in 32-bit  entities.
+        They are not compatible.
+
+             The FFP format consists of a 24  bit  mantissa,  1  bit  of
+        sign,  and  7  bits of exponent.  The exponent is stored in it's
+        two's complement form.
+
+           [ | | | | | | | ~~~~ | | | | | | | | | | | | | | | | ]
+           |------------ Mantissa --------------|S|---- Exp ----|
+
+        The IEEE format consists of 1 sign bit, 8 bits of exponent,  and
+        23  bits  of mantissa.  The exponent is store in it's Excess 127
+        format.
+
+           [ | | | | | | | | | | | | | | | ~~~~ | | | | | | | | ]
+           |S|----- Exp -----|---------- Mantissa --------------|
+
+        The floating point numbers represented by the IEEE format are  :
+        (-1)^S  *  1.F  * 2^E, the FFP floating point numbers are of the
+        form : (-1)^S * 0.F * 2^E.
+
+             The IEEE format will be used if the -e flag is given to the
+        compiler  or  if  the  -lE flag is given to the loader.  The FFP
+        format will be used if the -f flag is given to the  compiler  or
+        if  the  -lF  flag  is  given  to the loader.  These flags cause
+        floating point constants of the appropriate flavor  to  be  gen-
+        erated and the appropriate library to be loaded.
+
+             The IEEE floating point values lose some precision  due  to
+        the fact that calculations use the fast floating point routines,
+        and a  translation  to  and  from  the  FFP  format.   cc(cmnd),
+        lo(cmnd)
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