RESOURCE_SHARING

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• "RESOURCE_SHARING Description"
• "RESOURCE_SHARING Architecture Support"
• "RESOURCE_SHARING Applicable Elements"
• "RESOURCE_SHARING Propagation Rules"
• "RESOURCE_SHARING Syntax Examples"

RESOURCE_SHARING Description

RESOURCE_SHARING is a synthesis constraint. It enables or disables resource sharing of arithmetic operators. Allowed values are YES (check box is checked) and NO (check box is not checked). By default, resource sharing is enabled.

RESOURCE_SHARING Architecture Support

Virtex	Yes
Virtex-E	Yes
Spartan-II	Yes
Spartan-IIE	Yes
Virtex-II	Yes
Virtex-II Pro	Yes
XC9500, XC9500XL, XC9500XV	Yes
CoolRunner	Yes
CoolRunner II	Yes

RESOURCE_SHARING Applicable Elements

You can apply RESOURCE_SHARING globally or to design elements.

RESOURCE_SHARING Propagation Rules

Applies to the entity or module to which it is attached.

RESOURCE_SHARING Syntax Examples

ECS Schematic Editor

Not applicable.

VHDL

Before RESOURCE_SHARING can be used, it must be declared with the following syntax:

attribute resource_sharing: string; 

After RESOURCE_SHARING has been declared, specify the VHDL constraint as follows:

attribute resource_sharing of entity_name: entity is "yes"; 

For a more detailed discussion of the basic VHDL syntax, see the "VHDL" section of the "Constraint Entry" chapter.

Verilog

Specify as follows:

 // synthesis attribute resource_sharing [of] module_name [is] yes; 

For a more detailed discussion of the basic Verilog syntax, see the "Verilog" section of the "Constraint Entry" chapter.

ABEL

Not applicable.

NCF

Not applicable.

UCF

Not applicable.

Xilinx Constraints Editor

Not applicable.

PCF

Not applicable.

XST Constraint File

No attribute declaration is required. An attribute can be directly specified using the following syntax:

attribute resource_sharing of entity_name: entity is "{yes|no}"; 

The default value is YES.

For more details about the XST constraints file, see the "XST Constraint File" section of the "Constraint Entry" chapter.

FPGA Express Constraints Editor

Not applicable.

Floorplanner

Not applicable.

FPGA Editor

Not applicable.

XST Command Line

Define globally with the -resource_sharing command line option of the run command. Following is the basic syntax:

-resource_sharing {YES|NO} 

The default is YES.

See the "Command Line Mode" chapter in the XST User Guide for details.

Project Navigator

Set RESOURCE_SHARING globally with the Resource Sharing option in the HDL Options tab of the Process Properties dialog box within the Project Navigator.

With a design selected in the Sources window, right-click Synthesize in the Processes window to access the appropriate Process Properties dialog box.