( ESNUG 237 Item 4 ) ---------------------------------------------- [3/29/96]
From: ellement@sdd.hp.com (David Ellement)
Subject: Will Trade "How To Fake Out 2-D Arrays In Dc_shell" For "Functions"
Hello John,
Following the "offer a little, *then* ask for a little" philosophy, here's a
tidbit on list processing in dc_shell to simulate two dimensional arrays.
Often times I have wanted two addition features in the Design Compiler
script language: two dimensional arrays and functions. I have found
a (clumsy) workaround to simulate dimensional arrays using the built-in
list processing capability.
To simulate a two dimensional array, I use a list and add or delete
items as n-tuples:
array_list = { initial_row_1 initial_row_2 initial_row_3 }
...
array_list = array_list + { next_row_1 next_row_2 next_row_3 }
...
array_list = array_list + { last_row_1 last_row_2 last_row_3 }
Later, when I need to access a particular piece of information, I use
a foreach loop:
item_1 = item_2 = item_3 = ""
foreach (item, array_list) {
if (item_1 == "") {
item_1 = item
continue
}
if (item_2 == "") {
item_2 = item
continue
}
item_3 = item
/* use item_1, item_2, item_3 */
item_1 = item_2 = item_3 = ""
}
One use has been for a generic script to compile pieces of a design with
multiple clocks (not all of which are present in each piece) and for which
the name used for each clock is different in the different designs:
/* in an initialization script */
/* set clock data: { name period rising_edge skew } */
clock_list = { "Clk" 50 0 0.5 }
clock_list = clock_list + { "iClk" 50 25 0.8 }
...
/* in the generic script */
_name = _period = _rising_edge = _skew = ""
foreach (item, clock_list) {
if (_name == "") {
_name = item
continue
}
if (_period == "") {
_period = item
continue
}
if (_rising_edge == "") {
_rising_edge = item
continue
}
_skew = item
create_clock -name _name -period _period \
-waveform { _rising_edge _rising_edge + _period / 2 } _name
set_clock_skew -uncertainty _skew _name
_name = _period = _rising_edge = _skew = ""
}
Now I've contributed to ESNUG, I'd like to ask: Does anyone have a method to
provide something like "function" capability?
- David Ellement
Hewlett-Packard
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