Omron CS1G/H-CPUxxH Instructions Manual page 32

General Instruction Characteristics
Name
Floating-
31 30 29
point deci-
mal
Sign of
mantissa
• Sign (bit 31)
• Mantissa
• Exponent
Note This format conforms to IEEE754 standards for single-precision floating-point data
and is used only with instructions that convert or calculate floating-point data. It can
be used to set or monitor from the I/O memory Edit and Monitor Screen on the CX-
Programmer (not supported by the Programming Consoles). As such, users do not
need to know this format although they do need to know that the formatting takes up
two words.
Double-
63 62 61
precision
floating-
point deci-
mal
Sign of
mantissa
Note This format conforms to IEEE754 standards for double-precision floating-point
data and is used only with instructions that convert or calculate floating-point
data. It can be used to set or monitor from the I/O memory Edit and Monitor
Screen on the CX-Programmer (not supported by the Programming Consoles).
As such, users do not need to know this format although they do need to know
that the formatting takes up four words.
Signed Binary Numbers
Format
23 22 21 20 19 18 17
Exponent
Binary
Sign
Value = (−1) x 1.[Mantissa] x 2
1: negative or 0: positive
The mantissa includes 23 bits from bit 00 to bit 22
and indicates this portion below the decimal point
in 1.@@@..... in binary.
The exponent includes 8 bits from bit 23 to bit 30
and indicates n plus 127 in 2
52 51 50 49 48 47 46
Exponent
Binary
Sign
Value = (−1) x 1.[Mantissa] x 2
Sign (bit 63) 1: negative or 0: positive
Mantissa The 52 bits from bit 00 to bit 51 contain the mantissa,
i.e., the portion below the decimal point in 1.@@@.....,
in binary.
Exponent The 11 bits from bit 52 to bit 62 contain the exponent
The exponent is expressed in binary as 1023 plus n
n
in 2 .
Negative signed-binary numbers are expressed as the 2's complement of the
absolute hexadecimal value. For a decimal value of
value is equivalent to 3039 hexadecimal. The 2's complement is 10000
(both hexadecimal) or CFC7.
To convert from a negative signed binary number (CFC7) to decimal, take the
2's complement of that number (10000
(3039 hexadecimal = 12,345 decimal), and add a minus sign (
3 2 1
Mantissa
Exponent
n
in binary.
3 2 1
Mantissa
Exponent
–
Section 1-1
Decimal Hexadecimal
range
--- ---
0
--- ---
0
12,345, the absolute
–
CFC7 = 3039), convert to decimal
12,345).
–
range
3039
–
11