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| Number | 468
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| Category | errata
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| Synopsis | 4.2.1: Vector bit-select and part-select addressing
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| State | open
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| Class | errata-simple
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| Arrival-Date | Sep 14 2003
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| Originator | Krishna Garlapati <krishna@synplicity.com>
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| Release | 2001b: 4.2.1
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| Description |
In Section 4.2.1, page 53, the LRM says: "The first two examples select bits starting at the base and ascending the bit range. The number of bits selected is equal to the width expression. The second two examples select bits starting at the base and descending the bit range." There is no explanation of the term "starting at the base". It can be inferred, but I think the explanation should have been a little clear along the lines: big_vect[lsb_base_expr +: width_expr] is to be read as big_vect[lsb_base_expr+width_expr-1 : lsb_base_expr] if the range of big_vector is descending and as big_vect[lsb_base_expr : lsb_base_expr+width_expr-1] if the range of big_vector is ascending. I also think we should get rid of reg [15:0] big_vect; reg [0:15] little_vect; and replace them with reg [15:0] down_vect; reg [0:15] up_vect; The prefixes big and little make no meaning here given both are 15 bits wide. -- - Krishna Garlapati, Synplicity Inc. (408)215-6152 |
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From: Krishna Garlapati <krishna@synplicity.com> Reply-To: Krishna Garlapati <krishna@synplicity.com> X-Send-Pr-Version: gnatsweb-2.5 (1.2) X-GNATS-Notify: |
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