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Support .concat with arbitrary input counts.

This commit is contained in:
steve 2005-02-04 05:13:57 +00:00
parent b48abb2148
commit e74127e1fc
1 changed files with 64 additions and 6 deletions
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70
tgt-vvp/vvp_scope.c
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@ -17,7 +17,7 @@
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#ifdef HAVE_CVS_IDENT
#ident "$Id: vvp_scope.c,v 1.113 2005/02/03 04:56:21 steve Exp $"
#ident "$Id: vvp_scope.c,v 1.114 2005/02/04 05:13:57 steve Exp $"
#endif
# include "vvp_priv.h"
@ -1330,17 +1330,30 @@ static unsigned lpm_concat_inputs(ivl_lpm_t net, unsigned start,
return wid;
}
/*
* Implement the general IVL_LPM_CONCAT using .concat nodes. Use as
* many nested nodes as necessary to support the desired number of
* input vectors.
*/
static void draw_lpm_concat(ivl_lpm_t net)
{
const char*src_table[4];
unsigned icnt = ivl_lpm_selects(net);
if (icnt <= 4) {
/* This is the easies case. There are 4 or fewer input
vectors, so the entire IVL_LPM_CONCAT can be
implemented with a single .concat node. */
draw_lpm_data_inputs(net, 0, icnt, src_table);
fprintf(vvp_out, "L_%p .concat ", net);
lpm_concat_inputs(net, 0, icnt, src_table);
} else {
/* If there are more then 4 inputs, things get more
complicated. We need to generate a balanced tree of
.concat nodes to blend the inputs down to a single
root node, that becomes the output from the
concatenation. */
unsigned idx, depth;
struct concat_tree {
unsigned base;
@ -1349,6 +1362,10 @@ static void draw_lpm_concat(ivl_lpm_t net)
tree = malloc((icnt + 3)/4 * sizeof(struct concat_tree));
/* First, fill in all the leaves with the initial inputs
to the tree. After this loop, there are (icnt+3)/4
.concat nodes drawn, that together take all the
inputs. */
for (idx = 0 ; idx < icnt ; idx += 4) {
unsigned wid = 0;
unsigned trans = 4;
@ -1363,20 +1380,58 @@ static void draw_lpm_concat(ivl_lpm_t net)
tree[idx/4].wid = wid;
}
depth = 1;
icnt = (icnt + 3)/4;
/* Tree now has icnt nodes that are depth=0 concat nodes
which take in the leaf inputs. The while loop below
starts and ends with a tree of icnt nodes. Each time
through, there are 1/4 the nodes we started
with. Thus, we eventually get down to <=4 nodes, and
that is when we fall out of the loop. */
depth = 1;
while (icnt > 4) {
/* XXXX For now, only 4*4==16 inputs are
supported. To support an arbitrary count, this
loop needs to be filled in. */
assert(0);
for (idx = 0 ; idx < icnt ; idx += 4) {
unsigned tdx;
unsigned wid = 0;
unsigned trans = 4;
if ((idx+trans) > icnt)
trans = icnt - idx;
fprintf(vvp_out, "LS_%p_%u_%u .concat [",
net, depth, idx);
for (tdx = 0 ; tdx < trans ; tdx += 1) {
fprintf(vvp_out, " %u", tree[idx].wid);
wid += tree[idx].wid;
}
for ( ; tdx < 4 ; tdx += 1)
fprintf(vvp_out, " 0");
fprintf(vvp_out, "]");
for (tdx = 0; tdx < trans ; tdx += 1) {
fprintf(vvp_out, ", LS_%p_%u_%u", net,
depth-1, tree[idx+tdx].base);
}
fprintf(vvp_out, ";\n");
tree[idx/4].base = idx;
tree[idx/4].wid = wid;
}
depth += 1;
icnt = (icnt + 3)/4;
}
/* Finally, draw the root node that takes in the final
row of tree nodes and generates a single output. */
fprintf(vvp_out, "L_%p .concat [", net);
for (idx = 0 ; idx < icnt ; idx += 1)
fprintf(vvp_out, " %u", tree[idx].wid);
for ( ; idx < 4 ; idx += 1)
fprintf(vvp_out, " 0");
fprintf(vvp_out, "]");
for (idx = 0 ; idx < icnt ; idx += 1)
@ -1829,6 +1884,9 @@ int draw_scope(ivl_scope_t net, ivl_scope_t parent)
/*
* $Log: vvp_scope.c,v $
* Revision 1.114 2005/02/04 05:13:57 steve
* Support .concat with arbitrary input counts.
*
* Revision 1.113 2005/02/03 04:56:21 steve
* laborate reduction gates into LPM_RED_ nodes.
*