Freescale Semiconductor MC68881 - Page 84

4
FATAN Arc Tangent FATAN
Operation: Arc Tangent of Source J FPn
Assembler FATAN.<fmt> <ea>,FPn
Syntax: FATAN.X FPm,FPn
FATAN .X FPn
Attributes:
Description:
Format= (Byte, Word, Long, Single, Double, Extended, Packed)
Converts the source operand to extended precision (if necessary) and cal-
culates the arc tangent of that number. Stores the result in the destination floating-
point data register. The result is in the range of [-~/2 ... +~/2}.
Operation Table:
ce In Range
+
Result Arc Tangent
+ Zero _ [ + Infinity _ '
+0.0 0.0 J_ --.-:2 .-.2
NOTE: If the source operand is a NAN, refer to 4.5.4 NANs for more information.
Status Register:
Condition Codes:
Quotient Byte:
Affected as described in 4.5.5.1 SETTING FLOATING-POINT
CONDITION
CODES.
Not affected
Exception Byte:
Accrued Exception Byte:
BSUN
SNAN
OPERR
OVFL
UNFL
DZ
INEX2
INEX1
Cleared
Refer to 4.5.4
NANs.
Cleared
Cleared
Refer to 6.1.5 Underflow.
Cleared
Refer to 6.1.7 Inexact Result.
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
Instruction Format:
15 14 13
1 1 1
0 RIM 0
12 11 10 9 8 7 6 5 4 3 2 I 0
COPROCESSOR EFFECTIVF7 AD DRESS
I ID 0 0 O MODE I REGISTER
SOURCE DESTINATION , ' , i
SPECIFIER REGISTER 0 0 Jl0 1 0 1 I C
. !
FREESCALE
4-26
MC68881/MC68882 USER'S MANUAL