AH500 Programming Manual
6-342
API
Instruction code
Operand
Function
1514 FLOG P
S
1
, S
2
, D
Logarithm of the floating-point
number
Device
X Y M S T C HC D L SM SR E PR K 16#
“$” DF
Pulse instruction
16-bit instruction (7-9 steps)
32-bit instruction
AH500 AH500 -
Symbol:
S
1
：
Device in which the base is stored Double word
S
2
：
Source device Double word
D
：
Device in which the operation result is
stored
Double word
Explanation:
1. The logarithm of the value in S
2
with respect to the value in S
1
is calculated, and the operation
result is stored in D.
2. The values in S
1
and S
2
only can be positive values. The register specified by D should be a
32-bit register, and the values in S
1
and S
2
should be floating-point numbers.
3. S
1
D
=S
2
.→D=Log
S1
S
2
.
4. Example: Suppose the values in S
1
and S
2
are 5 and 125 respectively. Find log
5
125.
5. S
1
D
=S
2
.→5D=125.→D=log
5
125=3.
6. If the operation result stored in D is 0, SM600 is ON.
Example:
1. When X0.0 is ON, the values in (D1, D0) and (D3, D2) are converted into the floating-point
numbers, and the conversion results are stored in (D11, D10) and (D13, D12) respectively.
2. When X0.1 is ON, the logarithm of the floating-point number in (D13, D12) with respect to the
floating-point number in (D11, D10) is calculated, and the operation result is stored in (D21,
D20).
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