d·log (10)/log (T'Machine_Radix)
+1, where d is the requested decimal precision of T. In addition, it shall be less than or equal to the value of T'Machine_Mantissa. This attribute yields a value of the type universal_integer.
'Machine_Mantissa 24 53
'Machine_Emin -125 -1021
'Machine_Emax 128 1024
'Denorm True True
'Machine_Rounds True True
'Machine_Overflows True/False True/False
'Signed_Zeros should be True should be True
'Model_Emin (same as 'Machine_Emin) (same as 'Machine_Emin)
'Model_Epsilon 2.0**(-23) 2.0**(-52)
'Model_Small 2.0**(-126) 2.0**(-1022)
'Safe_First -2.0**128*(1.0-2.0**(-24)) -2.0**1024*(1.0-2.0**(-53))
'Safe_Last 2.0**128*(1.0-2.0**(-24)) 2.0**1024*(1.0-2.0**(-53))
'Base'Digits (same as 'Digits) (same as 'Digits)
'Last (same as 'Safe_Last) (same as 'Safe_Last)
'Size 32 64
d
is less than or equal to the function's maximum relative error. The function delivers a value that belongs to the result interval when both of its bounds belong to the safe range of EF.Float_Type; otherwise,
EF.Float_Type'Machine_Mantissa/2\
. Beyond the angle threshold, the accuracy of the forward trigonometric functions is implementation defined.
Tightly Approximated Elementary Function Results
Function
Value of X
Value of Y
Exact Result when Cycle Specified
Exact Result when Cycle Omitted
Arcsin
1.0
n.a.
Cycle/4.0
/2.0
Arcsin
-1.0
n.a.
-Cycle/4.0
- /2.0
Arccos
0.0
n.a.
Cycle/4.0
/2.0
Arccos
-1.0
n.a.
Cycle/2.0
Arctan and Arccot
0.0
positive
Cycle/4.0
/2.0
Arctan and Arccot
0.0
negative
-Cycle/4.0
- /2.0
Arctan and Arccot
negative
+0.0
Cycle/2.0
Arctan and Arccot
negative
-0.0
-Cycle/2.0
-
Arctan and Arccot
negative
0.0
Cycle/2.0
/2.0.
/2.0 (resp.,
).