Omron CJ - REFERENCE MANUAL 10-2009 Reference Manual page 57

Data type
Single
31 30 29
precision
floating
point
Exponent
decimal Sign of
mantissa
Sign (bit 31)
Mantissa
Exponent
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. As such, users do not need to know this for-
mat although they do need to know that the formatting takes up two words.
Double
63 62 52
precision
floating
point deci-
mal
Exponent
Sign of
mantissa
Sign (bit 63)
Mantissa
Exponent
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. As such, users do not need to know this for-
mat although they do need to know that the formatting takes up four words.
Note
CS/CJ/NSJ Series Instructions Reference Manual (W474)
Data format
23 22 21 20 19
Binary
Mantissa
Exponent
1.[Mantissa] 2
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
n
2 .
51
Mantissa
Binary
Exponent
1.[Mantissa] 2
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
n
in 2 .
1. Complements
Generally the complement of base x refers to a number produced when all
digits of a given number are subtracted from x
the rightmost digit.
(Example: The ten's complement of 7556 is 9999 7556 + 1 = 2444.)
A complement is used to express a subtraction and other functions as an
addition.
Example: With 8954 7556 = 1398, 8954 + (the ten's complement of 7556)
= 8954 + 2444 = 11398. If we ignore the leftmost bit, we get a subtraction
result of 1398.
2. Two's Complements
A two's complement is a base-two complement. Here, we subtract all digits
from 1 (2 1 = 1) and add one.
Example: The two's complement of binary number 1101 is 1111 (F Hex)
1101 (D Hex) + 1 (1 Hex) = 0011 (3 Hex). The following shows this value
expressed in 4-digit hexadecimal.
1. Basic Understanding of Instructions
Decimal
---
2 1 0
---
0
1 and then 1 is added to
4-digit
hexadecimal
---
1
---
19