509
Floating-point Math Instructions Section 3-14
Precautions The source data in S+1 and S must be in IEEE754 floating-point data format.
3-14-19 LOGARITHM: LOG(468)
Purpose Calculates the natural (base e) logarithm of a 32-bit floating-point number and
places the result in the specified result words.
Ladder Symbol
Variations
Applicable Program Areas
Operand Specifications
Underflow Flag UF ON if the absolute value of the result is too small to be
expressed as a 32-bit floating-point value.
Negative Flag N OFF
Name Label Operation
LOG(468)
S
R
S: First source word
R: First result word
Variations Executed Each Cycle for ON Condition LOG(468)
Executed Once for Upward Differentiation @LOG(468)
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 R
CIO Area CIO 0 to CIO 6142
Work Area W0 to W510
Holding Bit Area H0 to H510
Auxiliary Bit Area A0 to A958 A448 to A958
Timer Area T0000 to T4094
Counter Area C0000 to C4094
DM Area D0 to D32766
Indirect DM addresses
in binary
@ D0 to @ D32767
Indirect DM addresses
in BCD
*D0 to *D32767
Constants #00000000 to #FFFFFFFF
(binary)
---
Data Registers ---
Index Registers ---
Indirect addressing
using Index Registers
,IR0 to ,IR15
–2048 to +2047 ,IR0 to –2048 to +2047 ,IR15
DR0 to DR15, IR0 to IR15
,IR0+(++) to ,IR15+(++)
,–(– –)IR0 to, –(– –)IR15
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