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Altera_Forum's avatar
Altera_Forum
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16 years ago

Storing value in a reg

input [11:0] stimulus;

reg val;

always @(posedge clk)

val <=# 1 |(stimulus);

what should be the value stored in the register val? Is it the same as saying val = val | stimulus? And does value always store the lower bit of the stimulus since val is just 1 bit but stimulus is 12 bits?

Thanks.

1 Reply

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    The use of the '|' operator in this case is referred to as a reduction operator. val will get the bitwise OR of all the bits in stimulus. So basically if any bit in stimulus is set, val will be a '1', otherwise, it will be '0';

    It's the same as writing

    val <= stimulus[11] | stimulus[10] | stimulus[9] ..... | stimulus[1] | stimulus[0];

    only obviously signicantly shorter.

    Jake