Altera Floating-Point Manuel d'utilisateur télécharger pdf (Page 85)

Table 10-5: ALTFP_INV Megafunction Output Ports

Port Name Required Description

result[] Yes The floating-point inverse result of the value at the

data[]input port. 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 No Underflow exception output. Asserted when the result of

the inversion (after rounding) is a denormalized number.

zero No Zero exception output. Asserted when the value at the

result[] port is a zero.

division_by_zero No Division-by-zero exception output. Asserted when the

denominator input is a zero.

nan No NaN exception output. Asserted when an invalid inversion

occurs, such as the inversion of NaN. In this case, a NaN

value is output to the result[] port. Any operation

involving NaN also asserts the nan port.

Parameters

Table 10-6: ALTFP_INV 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.

UG-01058

2014.12.19

Parameters

10-5

ALTFP_INV IP Core

Altera Corporation

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Altera Floating-Point Manuel d'utilisateur Page 85