Altera Floating-Point - Manual (Page 53)

Port Name Required Description
overflow
Yes Overflow exception port. Asserted when the result of the addition or
subtraction, after rounding, exceeds or reaches infinity. Infinity is
defined as a number in which the exponent exceeds
2
WIDTH_EXP -1.
result[]
Yes Floating-point output result. Like the input values, the MSB is the sign,
the next MSBs are the exponent, and the LSBs are the mantissa. The size
of this port is the total width of the sign bit, exponent bits, and mantissa
bits.
underflow
Yes Underflow port for the adder or subtractor. Asserted when the result of
the addition or subtraction, after rounding, the value is zero and the
inputs are not equal. The
underflow
port is also asserted when the
result is a denormalized number.
zero
No Zero port for the adder or subtractor. Asserted when the
result[]
port
is zero.
ALTFP_ADD_SUB Parameters
Table 5-6: ALTFP_ADD_SUB Parameters
Parameter Name Type Required Description
DIRECTION
String Yes Specifies addition or subtraction operations. Values
are
ADD
,
SUB
, or
VARIABLE
. If this parameter is not
specified, the default is
ADD
. When the value is
VARIABLE
, the
add_sub
port determines whether the
operation is addition or subtraction. The
add_sub
port must be connected if the
DIRECTION
parameter
is set to
VARIABLE
. If the value is
ADD
or
SUB
, the
add_
sub
port is ignored.
PIPELINE
Integer No Specifies the latency in clock cycles used in the
ALTFP_ADD_SUB IP core. The
PIPELINE
parameter supports values of
7
through
14
. If this
parameter is not specified, the default value is
11
. In
general, a higher pipeline value produces better f
MAX
performance.
ROUNDING
String Yes Specifies the rounding mode. The default value is
TO_NEAREST
. Other rounding modes are currently
not supported.
OPTIMIZE
String No Defines the design preference, whether the design is
optimized for speed (faster f
MAX
), or optimized for
area (lower resource count). Values are
SPEED
and
AREA
. If this parameter is not specified, the default is
SPEED
.
5-6 ALTFP_ADD_SUB Parameters
UG-01058
2014.12.19
Altera Corporation ALTFP_ADD_SUB IP Core
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