odin: Fix the logic of splitting a large multiplier into multiple
smaller multipliers when the multiplication is larger than the hard
multiplier size available in the FPGA.
diff --git a/ODIN_II/SRC/include/multipliers.h b/ODIN_II/SRC/include/multipliers.h
index 5e7ba15..710688c 100644
--- a/ODIN_II/SRC/include/multipliers.h
+++ b/ODIN_II/SRC/include/multipliers.h
@@ -45,7 +45,7 @@
extern void find_hard_multipliers();
extern void add_the_blackbox_for_mults(FILE *out);
extern void define_mult_function(nnode_t *node, FILE *out);
-extern void split_multiplier(nnode_t *node, int a0, int b0, int a1, int b1);
+extern void split_multiplier(nnode_t *node, int a0, int b0, int a1, int b1, netlist_t *netlist);
extern void iterate_multipliers(netlist_t *netlist);
extern void clean_multipliers();
diff --git a/ODIN_II/SRC/multipliers.cpp b/ODIN_II/SRC/multipliers.cpp
index c4d0704..242afc0 100644
--- a/ODIN_II/SRC/multipliers.cpp
+++ b/ODIN_II/SRC/multipliers.cpp
@@ -48,8 +48,8 @@
int *mults = NULL;
void record_mult_distribution(nnode_t *node);
-void init_cascade_adder(nnode_t *node, nnode_t *a, int b);
void init_split_multiplier(nnode_t *node, nnode_t *ptr, int offa, int a, int offb, int b, nnode_t *node_a, nnode_t *node_b);
+void init_multiplier_adder(nnode_t *node, nnode_t *parent, int a, int b);
void split_multiplier_a(nnode_t *node, int a0, int a1, int b);
void split_multiplier_b(nnode_t *node, int a, int b1, int b0);
void pad_multiplier(nnode_t *node, netlist_t *netlist);
@@ -649,38 +649,37 @@
}
/*-------------------------------------------------------------------------
- * (function: init_cascade_adder)
+ * (function: init_multiplier_adder)
*
* This function is used to initialize an adder that is within
* a split multiplier.
*-----------------------------------------------------------------------*/
-void init_cascade_adder(nnode_t *node, nnode_t *a, int b)
-{
+void init_multiplier_adder(nnode_t *node, nnode_t *parent, int a, int b) {
+
int i, size;
node->type = ADD;
- node->related_ast_node = a->related_ast_node;
- node->traverse_visited = a->traverse_visited;
+ node->related_ast_node = parent->related_ast_node;
+ node->traverse_visited = parent->traverse_visited;
node->node_data = NULL;
/* Set size to be the maximum input size */
- size = a->output_port_sizes[0];
+ size = a;
size = (size < b) ? b : size;
/* Set new port sizes and parameters */
node->num_input_port_sizes = 2;
node->input_port_sizes = (int *)vtr::malloc(2 * sizeof(int));
- node->input_port_sizes[0] = a->output_port_sizes[0];
+ node->input_port_sizes[0] = a;
node->input_port_sizes[1] = b;
node->num_output_port_sizes = 1;
node->output_port_sizes = (int *)vtr::malloc(sizeof(int));
node->output_port_sizes[0] = size;
/* Set the number of input pins and clear pin entries */
- node->num_input_pins = a->output_port_sizes[0] + b;
- node->input_pins = (npin_t**)vtr::malloc(sizeof(void *) *
- (a->output_port_sizes[0] + b));
- for (i = 0; i < a->output_port_sizes[0] + b; i++)
+ node->num_input_pins = a + b;
+ node->input_pins = (npin_t**)vtr::malloc(sizeof(void *) * (a + b));
+ for (i = 0; i < a + b; i++)
node->input_pins[i] = NULL;
/* Set the number of output pins and clear pin entries */
@@ -718,7 +717,7 @@
* extending NOT contracting.
*
*-----------------------------------------------------------------------*/
-void split_multiplier(nnode_t *node, int a0, int b0, int a1, int b1)
+void split_multiplier(nnode_t *node, int a0, int b0, int a1, int b1, netlist_t *netlist)
{
nnode_t *a0b0, *a0b1, *a1b0, *a1b1, *addsmall, *addbig;
int i, size;
@@ -764,35 +763,46 @@
addsmall->name = (char *)vtr::malloc(strlen(node->name) + 6);
strcpy(addsmall->name, node->name);
strcat(addsmall->name, "-add0");
- init_cascade_adder(addsmall, a1b0, a0b1->output_port_sizes[0]);
+ // this addition will have a carry out in the worst case, add to input pins and connect then to gnd
+ init_multiplier_adder(addsmall, a1b0, a1b0->num_output_pins + 1, a0b1->num_output_pins + 1);
/* New node for the BIG add */
addbig = allocate_nnode();
addbig->name = (char *)vtr::malloc(strlen(node->name) + 6);
strcpy(addbig->name, node->name);
strcat(addbig->name, "-add1");
- init_cascade_adder(addbig, addsmall,
- a0b0->output_port_sizes[0] + a1b1->output_port_sizes[0]);
+ init_multiplier_adder(addbig, addsmall, addsmall->num_output_pins, a0b0->num_output_pins - b0 + a1b1->num_output_pins);
- /* Insert temporary pins for addsmall */
- for (i = 0; i < a0b1->output_port_sizes[0]; i++)
- connect_nodes(a0b1, i, addsmall, i);
- for (i = 0; i < a1b0->output_port_sizes[0]; i++)
- connect_nodes(a1b0, i, addsmall, i+a0b1->output_port_sizes[0]);
+ // connect inputs to port a of addsmall
+ for (i = 0; i < a1b0->num_output_pins; i++)
+ connect_nodes(a1b0, i, addsmall, i);
+ add_input_pin_to_node(addsmall, get_zero_pin(netlist), a1b0->num_output_pins);
+ // connect inputs to port b of addsmall
+ for (i = 0; i < a0b1->num_output_pins; i++)
+ connect_nodes(a0b1, i, addsmall, i + addsmall->input_port_sizes[0]);
+ add_input_pin_to_node(addsmall, get_zero_pin(netlist), a0b1->num_output_pins + addsmall->input_port_sizes[0]);
- /* Insert temporary pins for addbig */
- size = addsmall->output_port_sizes[0];
+ // connect inputs to port a of addbig
+ size = addsmall->num_output_pins;
for (i = 0; i < size; i++)
connect_nodes(addsmall, i, addbig, i);
+
+ // connect inputs to port b of addbig
+ for (i = b0; i < a0b0->output_port_sizes[0]; i++)
+ connect_nodes(a0b0, i, addbig, i - b0 + size);
+ size = size + a0b0->output_port_sizes[0] - b0;
for (i = 0; i < a1b1->output_port_sizes[0]; i++)
connect_nodes(a1b1, i, addbig, i + size);
- size = size + a1b1->output_port_sizes[0];
- for (i = 0; i < a0b0->output_port_sizes[0]; i++)
- connect_nodes(a0b0, i, addbig, i + size);
- /* Move original output pins for multiply to addbig */
- for (i = 0; i < addbig->num_output_pins; i++)
- remap_pin_to_new_node(node->output_pins[i], addbig, i);
+ // remap the multiplier outputs coming directly from a0b0
+ for (i = 0; i < b0; i++) {
+ remap_pin_to_new_node(node->output_pins[i], a0b0, i);
+ }
+
+ // remap the multiplier outputs coming from addbig
+ for (i = 0; i < addbig->num_output_pins; i++) {
+ remap_pin_to_new_node(node->output_pins[i+b0], addbig, i);
+ }
/* Probably more to do here in freeing the old node! */
vtr::free(node->name);
@@ -854,22 +864,20 @@
addsmall->name = (char *)vtr::malloc(strlen(node->name) + 6);
strcpy(addsmall->name, node->name);
strcat(addsmall->name, "-add0");
- init_cascade_adder(addsmall, a1b, a1 + b);
+ init_multiplier_adder(addsmall, a0b, b, a1b->num_output_pins);
/* Connect pins for addsmall */
- for (i = a0; i < a0b->output_port_sizes[0]; i++)
+ for (i = a0; i < a0b->num_output_pins; i++)
connect_nodes(a0b, i, addsmall, i-a0);
- for (i = a0b->output_port_sizes[0] - a0; i < a1+b; i++) /* Sign extend */
- connect_nodes(a0b, a0b->output_port_sizes[0]-1, addsmall, i);
- for (i = b+a1; i < (2 * (a1 + b)); i++)
- connect_nodes(a1b, i-(b+a1), addsmall, i);
+ for (i = 0; i < a1b->num_output_pins; i++)
+ connect_nodes(a1b, i, addsmall, i + addsmall->input_port_sizes[0]);
/* Move original output pins for multiply to new outputs */
for (i = 0; i < a0; i++)
remap_pin_to_new_node(node->output_pins[i], a0b, i);
- for (i = a0; i < node->num_output_pins; i++)
- remap_pin_to_new_node(node->output_pins[i], addsmall, i-a0);
+ for (i = 0; i < addsmall->num_output_pins; i++)
+ remap_pin_to_new_node(node->output_pins[i+a0], addsmall, i);
/* Probably more to do here in freeing the old node! */
vtr::free(node->name);
@@ -930,7 +938,7 @@
addsmall->name = (char *)vtr::malloc(strlen(node->name) + 6);
strcpy(addsmall->name, node->name);
strcat(addsmall->name, "-add0");
- init_cascade_adder(addsmall, ab1, a + b1);
+ init_multiplier_adder(addsmall, ab1, ab1->num_output_pins, a + b1);
/* Connect pins for addsmall */
for (i = b0; i < ab0->output_port_sizes[0]; i++)
@@ -1134,7 +1142,7 @@
a1 = mula - sizea;
b0 = sizeb;
b1 = mulb - sizeb;
- split_multiplier(node, a0, b0, a1, b1);
+ split_multiplier(node, a0, b0, a1, b1, netlist);
}
else if (mula > sizea) /* split multiplier on a input? */
{
