4
FLOGN Lo. FLOGN
Operation:
Loge of Source $ FPn
Assembler FLOGN.<fmt> <ea>,FPn
Syntax:
FLOGN.X FPm,FPn
FLOGN.X FPn
Attributes: Format= (Byte, Word, Long, Single, Double, Extended, Packed)
Description: Converts the source operand to extended precision (if necessary) and cal-
culates the natural logarithm of that number. Stores the result in the destination
floating-point data register. This function is not defined for input values less than zero.
Operation Table:
Source In
Range Zero
Destination
~ + - + -
Result In(x) NAN 1 -inf 2
NOTES:
1. Sets the OPERR bit in the FPSR exception byte.
2. Sets the DZ bit in the FPSR exception byte,
3. If the source operand is a NAN, refer to 4.5.4 NANs for more information.
Status Register:
Condition Codes:
Infinity
-F
+inf NAN 1
Affected as described in 4.5.5,1 SETTING FLOATING-POINT
CONDITION
CODES
Quotient Byte: Not affected
Exception Byte: BSUN
SNAN
OPERR
Cleared
Refer to 4.5.4 NANs.
Set if the source operand is < 0; cleared
otherwise
OVFL Cleared
UNFL Cleared
DZ Set if the source is (+ or -)0; cleared other-
wise
]NEX2 Refer to 6.1.7 Inexact Result.
INEX1 If <fmt> is Packed, refer to 6.1.8 Inexact Result
on
Decimal Input; cleared otherwise.
Affected as described in 6.1.10
IEEE Exception and
Trap Com-
patibility
Accrued Exception Byte:
Instruction Format:
15 14 13
1 1
0 RIM 0
12 II 10 9 8 7 6 5 4 3 2 1
]COPROCESSOR J
EFFECTIV~ ADDRESS
1 ID 0 0 0 MODE 1 REG}STER
SOURCE DESTINATION I I [ i
SPECIFIER REGISTER 0 0 1 0 1 0 0
FREESCALE
4-58
MC68881/MC68882 USER'S MANUAL
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