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Handle adders that use Cout for the top bit.

This commit is contained in:
steve 2003-10-31 03:45:50 +00:00
parent 7fd669fcc0
commit c4e069e505
1 changed files with 25 additions and 5 deletions
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30
tgt-fpga/d-lpm.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: d-lpm.c,v 1.9 2003/10/27 02:18:27 steve Exp $"
#ident "$Id: d-lpm.c,v 1.10 2003/10/31 03:45:50 steve Exp $"
#endif
/*
@ -644,6 +644,7 @@ static void lpm_show_mux(ivl_lpm_t net)
static void lpm_show_add(ivl_lpm_t net)
{
unsigned idx;
unsigned cell_width;
char cellname[32];
edif_cell_t cell;
edif_cellref_t ref;
@ -654,18 +655,27 @@ static void lpm_show_add(ivl_lpm_t net)
if (ivl_lpm_type(net) == IVL_LPM_SUB)
type = "SUB";
/* Figure out the width of the cell. Normally, it is the LPM
width known by IVL. But if the top data input bits are
unconnected, then we really have a width one less, and we
can use the cout to fill out the output width. */
cell_width = ivl_lpm_width(net);
if ( (ivl_lpm_data(net,cell_width-1) == 0)
&& (ivl_lpm_datab(net,cell_width-1) == 0) )
cell_width -= 1;
/* Find the correct ADD/SUB device in the library, search by
name. If the device is not there, then create it and put it
in the library. */
sprintf(cellname, "%s%u", type, ivl_lpm_width(net));
sprintf(cellname, "%s%u", type, cell_width);
cell = edif_xlibrary_findcell(xlib, cellname);
if (cell == 0) {
unsigned pins = ivl_lpm_width(net) * 3 + 1;
unsigned pins = cell_width * 3 + 1;
cell = edif_xcell_create(xlib, strdup(cellname), pins);
for (idx = 0 ; idx < ivl_lpm_width(net) ; idx += 1) {
for (idx = 0 ; idx < cell_width ; idx += 1) {
sprintf(cellname, "Result%u", idx);
edif_cell_portconfig(cell, idx*3+0, strdup(cellname),
@ -691,7 +701,7 @@ static void lpm_show_add(ivl_lpm_t net)
/* Connect the pins of the instance to the nexa. Access the
cell pins by name. */
for (idx = 0 ; idx < ivl_lpm_width(net) ; idx += 1) {
for (idx = 0 ; idx < cell_width ; idx += 1) {
unsigned pin;
sprintf(cellname, "Result%u", idx);
@ -712,6 +722,13 @@ static void lpm_show_add(ivl_lpm_t net)
jnt = edif_joint_of_nexus(edf, ivl_lpm_datab(net, idx));
edif_add_to_joint(jnt, ref, pin);
}
if (cell_width < ivl_lpm_width(net)) {
unsigned pin = edif_cell_port_byname(cell, "Cout");
jnt = edif_joint_of_nexus(edf, ivl_lpm_q(net, cell_width));
edif_add_to_joint(jnt, ref, pin);
}
}
static void lpm_show_mult(ivl_lpm_t net)
@ -858,6 +875,9 @@ const struct device_s d_lpm_edif = {
/*
* $Log: d-lpm.c,v $
* Revision 1.10 2003/10/31 03:45:50 steve
* Handle adders that use Cout for the top bit.
*
* Revision 1.9 2003/10/27 02:18:27 steve
* Emit constants for LPM device.
*