Omron CP - PROGRAMMING MANUAL 05-2007 - Page 47

14
Programming Concepts Section 1-1
Signed Binary Data
In signed binary data, the leftmost bit indicates the sign of binary 16-bit data.
The value is expressed in 4-digit hexadecimal.
Positive Numbers: A value is positive or 0 if the leftmost bit is 0 (OFF). In 4-
digit hexadecimal, this is expressed as 0000 to 7FFF hex.
Negative Numbers: A value is negative if the leftmost bit is 1 (ON). In 4-digit
hexadecimal, this is expressed as 8000 to FFFF hex. The absolute of the neg-
ative value (decimal) is expressed as a two’s complement.
Single-pre-
cision
floating-
point deci-
mal
Note This format conforms to IEEE754 standards for single-precision floating-
point data and is used only with instructions that convert or calculate float-
ing-point data. It can be used to set or monitor from the I/O memory Edit
and Monitor Screen on the CX-Programmer. As such, users do not need to
know this format although they do need to know that the formatting takes
up two words.
--- ---
Double-
precision
floating-
point deci-
mal
Note This format conforms to IEEE754 standards for double-precision floating-
point data and is used only with instructions that convert or calculate float-
ing-point data. It can be used to set or monitor from the I/O memory Edit
and Monitor Screen on the CX-Programmer. As such, users do not need to
know this format although they do need to know that the formatting takes
up four words.
--- ---
Data type Data format Decimal 4-digit
hexadecimal
31 30 29 23 22 21 20 19 18 17 3 2 1 0
Sign of
mantissa
Exponent
Mantissa
x 1.[Mantissa] x 2
Exponent
Sign (bit 31)
Mantissa
Exponent
1: negative or 0: positive
The 23 bits from bit 00 to bit 22 contain the mantissa,
i.e., the portion below the decimal point in 1.@@@.....,
in binary.
The 8 bits from bit 23 to bit 30 contain the exponent.
The exponent is expressed in binary as 127 plus n in
2
n
.
Value = (−1)
Sign
Binary
63 62 61 52 51 50 49 48 47 46 3 2 1 0
Exponent Mantissa
x 1.[Mantissa] x 2
Exponent
Sign (bit 63)
Mantissa
Exponent
Sign
Value = (−1)
Sign of
mantissa
Binary
1: negative or 0: positive
The 52 bits from bit 00 to bit 51 contain the mantissa,
i.e., the portion below the decimal point in 1.@@@.....,
in binary.
The 11 bits from bit 52 to bit 62 contain the exponent
The exponent is expressed in binary as 1023 plus n
in 2
n
.