560
Double-precision Floating-point Instructions Section 3-15
Flags
Precautions The source data in words S to S+3 must be in IEEE754 floating-point data for-
mat.
3-15-19 DOUBLE LOGARITHM: LOGD(859)
Purpose Calculates the natural (base e) logarithm of a double-precision (64-bit) float-
ing-point number and places the result in the specified destination words.
Ladder Symbol
Variations
Applicable Program Areas
Operand Specifications
Name Label Operation
Error Flag ER ON if the source data is not recognized as floating-point
data.
ON if the source data is not a number (NaN).
OFF in all other cases.
Equals Flag = ON if both the exponent and mantissa of the result are 0.
OFF in all other cases.
Overflow Flag OF ON if the absolute value of the result is too large to be
expressed as a double-precision (64-bit) floating-point
value.
Underflow Flag UF ON if the absolute value of the result is too small to be
expressed as a double-precision (64-bit) floating-point
value.
Negative Flag N Unchanged
LOGD(859)
S
D
S: First source word
D: First destination word
Variations Executed Each Cycle for ON Condition LOGD(859)
Executed Once for Upward Differentiation @LOGD(859)
Executed Once for Downward Differentiation Not supported.
Immediate Refreshing Specification Not supported.
Block program areas Step program areas Subroutines Interrupt tasks
OK OK OK OK
Area S D
CIO Area CIO 0 to CIO 6140
Work Area W0 to W508
Holding Bit Area H0 to H508
Auxiliary Bit Area A0 to A956 A448 to A956
Timer Area T0000 to T4092
Counter Area C0000 to C4092
DM Area D0 to D32764
Indirect DM addresses
in binary
@ D0 to @ D32767
Indirect DM addresses
in BCD
*D0 to *D32767
Constants ---
Data Registers ---
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