Re: [sv-bc] constant_range_expression in constant_primary

Am I correct in assuming that the concatenation indexing syntax {...}[] is intended only for (packed array) concatenations and not for unpacked array concatenations?

Paul
----- Original Message -----
From: "Shalom Bresticker" <shalom.bresticker@intel.com>
To: "Laurence S Bisht" <laurence.s.bisht@intel.com>, sv-bc@eda.org
Cc: sv-ac@eda.org
Sent: Wednesday, January 26, 2011 6:38:09 AM
Subject: RE: [sv-bc] constant_range_expression in constant_primary

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_identifier 35

| [ 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_reference 36

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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