enhancement/401: reduce relational operators x-pessimism

From: Shalom.Bresticker@motorola.com
Date: Fri Jul 25 2003 - 01:53:02 PDT

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    >Number: 401
    >Category: enhancement
    >Originator: Shalom.Bresticker@motorola.com
    >Environment:
    >Description:

    Today, 4.1.7 says,
    "If either operand of a relational operator contains an unknown (x)
    or high impedance (z) value, then the result value shall be a 1-bit unknown
    value (x)."

    There are cases where it is clearly possible to be less conservative.
    For example, for 4'b1000 > 4'b000x, then clearly the result could be 1'b1
    instead of 1'bx. 

    -- 
Shalom Bresticker                           Shalom.Bresticker@motorola.com
Design & Reuse Methodology                             Tel: +972 9 9522268
Motorola Semiconductor Israel, Ltd.                    Fax: +972 9 9522890
POB 2208, Herzlia 46120, ISRAEL                       Cell: +972 50 441478

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