88
3 CONFIGURATION OF INSTRUCTIONS
3.2 Designating Data
Double-precision real number data (double-precision floating-point data)
Instructions which deal with double-precision floating-point data designate devices which are used for the lower 16 bits of
data.
Double-precision floating-point data are stored in the 64 bits which make up (designated device number) to (designated
device number + 3).
In a sequence program, floating-point data are designated by E.
Double-precision floating-point data can be represented as follows, using four word devices.
[Sign] 1.[Mantissa] 2
[Exponent]
The bit configuration and meaning for the internal representation of double-precision floating-point data are described below:
• Sign: The most significant bit, b63, is the sign bit.
• Exponent: The 11 bits, b52 to b62, represent the excess n of 2
n
. The following shows the excess n according to the binary
values in b52 to b62.
• Mantissa: Each of the 52 bits, b0 to b51, represents the "XXXXXX..." portion when the data is represented in binary,
"1.XXXXXX...".
• 0: Positive
•1: Negative
Designation of 4 points of R100, R101, R102 and
R103 (64 bits)
M0
EDMOV R100
D0
Designation of 4 points of word devices D0, D1, D2
and D3 (64 bits)
Double-precision floating-point data transfer
instruction
b63 b62
to
b52 b51b16
to
b15 b0
to
b63
Sign
b52 to b62
Exponent
b0 to 51
Mantissa
b52 to b62 7FFH 7FEH 7FDH 400H 3FFH 3FEH 3FCH 02H 01H 00H
n
Not used
1023 1022
3FD
H
-2 -301 -1 -1021 -1022 Not used
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