Altera Floating-Point - Manual (Page 92)

Table 11-7: ALTFP_INV_SQRT Megafunction Parameters
Parameter Name Type Required Description
WIDTH_EXP
Integer Yes Specifies the precision of the exponent. If this
parameter is not specified, the default is
8
. The bias
of the exponent is always set to
2 (WIDTH_EXP -1) -1
,
that is,
127
for the single-precision format and
1023
for the double-precision format. The value of the
WIDTH_EXP
parameter must be
8
for the single-
precision format,
11
for the double-precision
format, and a minimum of
11
for the single-
extended precision format. The value of the
WIDTH_
EXP
parameter must be less than the value of the
WIDTH_MAN
parameter, and the sum of the
WIDTH_
EXP
and
WIDTH_MAN
parameters must be less than
64
.
WIDTH_MAN
Integer Yes Specifies the value of the mantissa. If this parameter
is not specified, the default is
23
. When the
WIDTH_
EXP
parameter is
8
and the floating-point format is
single-precision, the
WIDTH_MAN
parameter value
must be
23
. Otherwise, the value of the
WIDTH_MAN
parameter must be a minimum of
31
. The value of
the
WIDTH_MAN
parameter must be greater than the
value of the
WIDTH_EXP
parameter. The sum of the
WIDTH_EXP
and
WIDTH_MAN
parameters must be less
than
64
.
PIPELINE
Integer Yes Specifies the amount of latency, expressed in clock
cycles, used in the ALTFP_INV_SQRT megafunc‐
tion. Create the ALTFP_INV_SQRT megafunction
with the MegaWizard Plug-In Manager to calculate
the value for this parameter.
ROUNDING
String No Specifies the rounding mode. The default value is
TO_NEAREST
. Other rounding modes are not
supported.
11-6 Parameters
UG-01058
2014.12.19
Altera Corporation ALTFP_INV_SQRT IP Core
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