Date: Wed Jan 26 2011 - 03:38:09 PST
You can't write 4'b1100[2:1], but rather {4'b1100}[2:1].
See 11.4.12:
"One or more bits of a concatenation can be selected as if the concatenation were a packed array with the range [n-1:0]. Such a select shall not be legal as a net_lvalue, variable_lvalue or in any equivalent use, such as on the left-hand side of an assignment. Example:
byte a, b ;
bit [1:0] c ;
c = {a + b}[1:0]; // 2 lsb's of sum of a and b"
Shalom
From: owner-sv-bc@eda.org [mailto:owner-sv-bc@eda.org] On Behalf Of Bisht, Laurence S
Sent: Wednesday, January 26, 2011 1:22 PM
To: sv-bc@eda.org
Cc: av-ac@eda.org
Subject: [sv-bc] constant_range_expression in constant_primary
Hello,
I am trying to understand why in constant_primary there exists [constant_range_expression] after constant_concatenation ? or after specparam_identifier?
constant_primary ::=
primary_literal
| ps_parameter_identifier constant_select
| specparam_identifier [ [ constant_range_expression ] ]
| genvar_identifier35
| [ package_scope | class_scope ] enum_identifier
| constant_concatenation [ [ constant_range_expression ] ]
| constant_multiple_concatenation [ [ constant_range_expression ] ]
| constant_function_call
| constant_let_expression
| ( constant_mintypmax_expression )
| constant_cast
| constant_assignment_pattern_expression
| type_reference36
My immediate guess is to be able to write 4'b1100[2:1].
However, I am sure that there exists a better explanation, can you please help?
Thanks,
Laurence
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