From: Tom Fitzpatrick (tfitz@cadence.com)
Date: Wed Apr 14 1999 - 07:55:24 PDT
BAD MSG:
Thanks Adam. That's not what I was hoping to hear, however.
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But this does get me thinking a bit. If I use a for loop in a generate
statement, then aren't I actually producing an array of generated
instances? The current proposal doesn't specify how to subscript each
instance explicitly.
The nested example given is:
parameter SIZE = 2;
genvar i, j, k, m;
generate
for (i=0; i<SIZE+1; i=i+1) begin
M1 N1(); // instantiates N1[i]
for (j=0; j<SIZE; j=j+1) begin
M2 N2(); // instantiates N2[i][j]
for (k=0; k<SIZE; k=k+1) begin
M3 N3(); // instantiates N3[i][j][k]
end
end
if (i>0)
for (m=0; m<SIZE; m=m+1) begin
M4 N4(); // instantiates N4[i][m]
end
end
endgenerate
// some of the generated instance names are:
// N1[0]
// N2[0][0] N2[0][1]
// N3[0][0][0] N3[0][0][1] N3[0][1][0] N3[0][1][1]
// N4[1][0] N4[1][1]
// Note: there are no instance names N1 N2 N3 N4
The only problem with this is that it forces the naming of each instance to
begin with the outermost genvar and proceed inward. If for some reason I
wanted to arrange my instances of M2 to be N2[i][j], but my instances of M3
to be N3[k][j][i], I couldn't do it. It also doesn't make it entirely
intuitive when a generated instance has a subscript and when it doesn't.
I'd like to propose a friendly ammendment to this proposal that will
explicitly require the genvar in the instance name of an instance array.
The above example would then look like this:
parameter SIZE = 2;
genvar i, j, k, m;
generate
for (i=0; i<SIZE+1; i=i+1) begin
M1 N1[i](); // instantiates N1[i]
for (j=0; j<SIZE; j=j+1) begin
M2 N2[i][j](); // instantiates N2[i][j]
for (k=0; k<SIZE; k=k+1) begin
M3 N3[i][j][k](); // instantiates N3[i][j][k]
M3a N3a[k][j][i](); // Instantiates N3a[k][j][i]
end
end
if (i>0)
for (m=0; m<SIZE; m=m+1) begin
M4 N4[i][m](); // instantiates N4[i][m]
end
end
endgenerate
<p>Fire away!
-Tom
---------------
Tom Fitzpatrick
Senior Technical Marketing Manager Cadence Design Systems, Inc.
RTL Verification Flow/Product Engineering 270 Billerica Rd.
Design and Verification R&D Chelmsford, MA 01824
x6438 (978)446-6438
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