The built-in floating point values in Quartus Forth are in Motorola Fast Floating Point (FFP) format. Each float is 4 bytes (32 bits) long, defined as follows:
3 2 1 10987654321098765432109876543210 MMMMMMMMMMMMMMMMMMMMMMMMSEEEEEEE
M..M
is the mantissa, forming an unsigned 24-bit
integer of value m.
E..E
is the binary exponent, forming an unsigned
7-bit integer of value e.
S
is the sign, 0 or 1.
The value of an FFP number is either 0 if all bits are 0, or computed as follows:
(-1)S * m * 2e-88
Quartus Forth supports zero and non-zero floating point values within the following bounds:
Base 10:9.22337177 x 1019 > +number > 5.42101070 x 10-20
-9.22337177 x 1019 > -number > -2.71050535 x 10-20
Base 2:
.FFFFFF x 263 > +number > .FFFFFF x 2-63
-.FFFFFF x 263 > -number > -.FFFFFF x 2-63