Altera Floating-Point Instrukcja Użytkownika Strona 53

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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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