Altera Integer Arithmetic IP Bedienungsanleitung PDF herunterladen (Seite 37)

Parameter Name Type Required Description

MAXIMIZE_SPEED Integer No Altera-specific parameter. You must use

the LPM_HINT parameter to specify the

MAXIMIZE_SPEED parameter in VHDL

design files. You can specify a value

between 0 and 10. If used, the Quartus II

software attempts to optimize a specific

instance of the LPM_MULT function for

speed rather than area, and overrides the

setting of the Optimization Technique

logic option. If MAXIMIZE_SPEED is unused,

the value of the Optimization Technique

option is used instead. For a SIGNED

multiplier with no inputs being a constant,

if the setting for MAXIMIZE_SPEED is 9-10,

the Compiler optimizes the LPM_MULT

megafunction for larger area. These

settings are for backward compatibility

only. If the setting is between 6-8, the

Compiler optimizes for larger area and

higher speed. If the setting is between 1-5,

the Compiler optimizes for smaller area

and high speed. If the setting is 0, the

smallest and, generally, slowest design

results. For designs with LPM_WIDTHB

parameters that are non-power-of-2, the

default setting is 1-5. For designs with

LPM_WIDTHB parameters that are a power-

of-2, the default value is 6-8. For an

UNSIGNED multiplier with no inputs being a

constant, if the setting for MAXIMIZE_

SPEED is 6 or higher, the Compiler

optimizes for larger area and higher speed.

If the setting is 0 up to 5, which is the

default value, the Compiler optimizes for

smaller area. Note that specifying a value

for MAXIMIZE_SPEED has an effect only if

LPM_REPRESENTATION is set to SIGNED.

DEDICATED_MULTIPLIER_CIRCUITRY

String No Specifies whether to use the default

dedicated multiplier circuitry implementa‐

tion. Values are AUTO, YES, NO, and FIRM. If

omitted, the default value is AUTO. For

Stratix and Stratix GX devices, the value of

AUTO specifies that the Quartus II software

determines whether to use the dedicated

multiplier circuitry based on the multiplier

width. If a device does not have dedicated

multiplier circuitry, the DEDICATED_

MULTIPLIER_CIRCUITRY parameter has no

effect and the value defaults to NO.

4-6

LPM_MULT Parameters

UG-01063

2014.12.19

Altera Corporation

LPM_MULT (Multiplier)

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