Altera Floating-Point - Manual (Page 61)

Port Name Required Description
overflow
No Overflow port for the divider. Asserted when the result of the division
(after rounding) exceeds or reaches infinity. Infinity is defined as a
number in which the exponent exceeds
2
WIDTH_EXP–1.
underflow
No Underflow port for the divider. Asserted when the result of the
division (after rounding) is zero even though neither of the inputs to
the divider is zero, or when the result is a denormalized number.
zero
No Zero port for the divider. Asserted when the value of
result[]
is
zero.
division_by_
zero
No Division-by-zero output port for the divider. Asserted when the value
of
datab[] is a zero.
nan
No NaN port. Asserted when an invalid division occurs, such as infinity
dividing infinity or zero dividing zero. A NaN value appears as
output at the
result[]
port. Any division of a NaN value causes the
nan
output port to be asserted.
ALTFP_DIV Parameters
Table 6-7: ALTFP_DIV 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 single precision and 1023 for double
precision. The value of
WIDTH_EXP
must be
8
for single
precision,
11
for double precision, and a minimum of
11 for single extended precision.
The value of
WIDTH_EXP
must be less than the value of
WIDTH_MAN
, and the sum of
WIDTH_EXP
and
WIDTH_MAN
must be less than
64
.
WIDTH_MAN
Integer Yes Specifies the precision of the mantissa. If this
parameter is not specified, the default is
23
. When
WIDTH_EXP
is
8
and the floating-point format is the
single-precision format, the
WIDTH_MAN
value must be
23
. Otherwise, the value of
WIDTH_MAN
must be a
minimum of
31
.
The value of
WIDTH_MAN
must be greater than the value
of
WIDTH_EXP
, and the sum of
WIDTH_EXP
and
WIDTH_
MAN
must be less than
64
.
ROUNDING
String Yes Specifies the rounding mode. The default value is
TO_
NEAREST
. The floating-point divider does not support
other rounding modes.
UG-01058
2014.12.19
ALTFP_DIV Parameters 6-7
ALTFP_DIV IP Core Altera Corporation
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