errata/428: PROPOSAL - 2.5.1, value of 16'shc, request for clarification

From: Brad.Pierce@synopsys.com
Date: Thu Aug 28 2003 - 10:45:19 PDT

  • Next message: Steven Sharp: "Re: errata/428: PROPOSAL - 2.5.1, value of 16'shc, request for clarification"

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    In Example 4 of 2.5.1

    REPLACE

    reg[11:0] a, b, c, d;
    initial begin
           a = 'h x; // yields xxx
           b = 'h 3x; // yields 03x
           c = 'h z3; // yields zz3
           d = 'h 0z3; // yields 0z3
    end
    reg [84:0] e, f, g;

           e = 'h5; // yields {82{1'b0}, 3'b101}
           f = 'hx; // yields {85{1'hx}}
           g = 'hz; // yields {85{1'hz}}

    WITH

    reg[11:0] a, b, c, d;
    initial begin
           a = 'h x; // yields 12'h xxx
           b = 'h 3x; // yields 12'h 03x
           c = 'h z3; // yields 12'h zz3
           d = 'h 0z3; // yields 12'h 0z3
    end
    reg [84:0] e, f, g, h, i;
    reg signed [84:0] j, k;

           e = 'h5; // yields {{82{1'b0}}, 3'b101}
           f = 'hx; // yields {85{1'bx}}
           g = 'hz; // yields {85{1'bz}}
           h = 4'hx; // yields {{81{1'b0}}, 4'hx}
           i = 16'ox; // yields {{69{1'b0}}, {16{1'bx}}}
           j = 16'sb110; // yields {{82{1'b0}}, 3'b110}
           k = 3'sb110; // yields {{82{1'b1}}, 3'b110}

    and

    REPLACE

    NOTES:

    1) Sized negative constant numbers and sized unsigned
    constant numbers are sign-extended when assigned to a
    reg data type, regardless of whether the reg itself is
    signed or not.

    2) Each of the three tokens for specifying a number
    may be macro substituted.

    3) The number of bits that make up an unsized number
    (which is a simple decimal number or a number without
    the size specification) shall be at least 32.

    WITH

    Sized negative constant numbers and sized unsigned
    constant numbers shall be sign-extended when assigned to a
    reg data type, regardless of whether the reg itself is
    signed or not.

    It shall be legal to macro substitute the three tokens
    for specifying a number.

    The number of bits that make up an unsized number
    (which is a simple decimal number or a number without
    the size specification) shall be at least 32.

    http://boydtechinc.com/cgi-bin/issueproposal.pl?cmd=view&pr=428

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