diff options
Diffstat (limited to 'src/intersim/islip.cpp')
| -rw-r--r-- | src/intersim/islip.cpp | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/src/intersim/islip.cpp b/src/intersim/islip.cpp new file mode 100644 index 0000000..1aafacc --- /dev/null +++ b/src/intersim/islip.cpp @@ -0,0 +1,185 @@ +#include "booksim.hpp"
+#include <iostream>
+
+#include "islip.hpp"
+#include "random_utils.hpp"
+
+//#define DEBUG_ISLIP
+
+iSLIP_Sparse::iSLIP_Sparse( const Configuration &config,
+ Module *parent, const string& name,
+ int inputs, int outputs ) :
+SparseAllocator( config, parent, name, inputs, outputs )
+{
+ _iSLIP_iter = config.GetInt( "alloc_iters" );
+
+ _grants = new int [_outputs];
+ _gptrs = new int [_outputs];
+ _aptrs = new int [_inputs];
+
+ for ( int i = 0; i < _inputs; ++i ) {
+ _aptrs[i] = 0;
+ }
+ for ( int j = 0; j < _outputs; ++j ) {
+ _gptrs[j] = 0;
+ }
+}
+
+iSLIP_Sparse::~iSLIP_Sparse( )
+{
+ delete [] _grants;
+ delete [] _gptrs;
+ delete [] _aptrs;
+}
+
+void iSLIP_Sparse::Allocate( )
+{
+ int input;
+ int output;
+
+ int input_offset;
+ int output_offset;
+
+ list<sRequest>::iterator p;
+ bool wrapped;
+
+ _ClearMatching( );
+
+ for ( int iter = 0; iter < _iSLIP_iter; ++iter ) {
+ // Grant phase
+
+ for ( output = 0; output < _outputs; ++output ) {
+ _grants[output] = -1;
+
+ // Skip loop if there are no requests
+ // or the output is already matched
+ if ( ( _out_req[output].empty( ) ) ||
+ ( _outmatch[output] != -1 ) ) {
+ continue;
+ }
+
+ // A round-robin arbiter between input requests
+ input_offset = _gptrs[output];
+
+ p = _out_req[output].begin( );
+ while ( ( p != _out_req[output].end( ) ) &&
+ ( p->port < input_offset ) ) {
+ p++;
+ }
+
+ wrapped = false;
+ while ( (!wrapped) || ( p->port < input_offset ) ) {
+ if ( p == _out_req[output].end( ) ) {
+ if ( wrapped ) {
+ break;
+ }
+ // p is valid here because empty lists
+ // are skipped (above)
+ p = _out_req[output].begin( );
+ wrapped = true;
+ }
+
+ input = p->port;
+
+ // we know the output is free (above) and
+ // if the input is free, grant request
+ if ( _inmatch[input] == -1 ) {
+ _grants[output] = input;
+ break;
+ }
+
+ p++;
+ }
+ }
+
+#ifdef DEBUG_ISLIP
+ cout << "grants: ";
+ for ( int i = 0; i < _outputs; ++i ) {
+ cout << _grants[i] << " ";
+ }
+ cout << endl;
+
+ cout << "aptrs: ";
+ for ( int i = 0; i < _inputs; ++i ) {
+ cout << _aptrs[i] << " ";
+ }
+ cout << endl;
+#endif
+
+ // Accept phase
+
+ for ( input = 0; input < _inputs; ++input ) {
+
+ if ( _in_req[input].empty( ) ) {
+ continue;
+ }
+
+ // A round-robin arbiter between output grants
+ output_offset = _aptrs[input];
+
+ p = _in_req[input].begin( );
+ while ( ( p != _in_req[input].end( ) ) &&
+ ( p->port < output_offset ) ) {
+ p++;
+ }
+
+ wrapped = false;
+ int flag ;
+ if ( p != _in_req[input].end( ) ) {
+ flag= (p->port < output_offset) ;
+ } else {
+ flag = true;
+ }
+ while ( (!wrapped) || (flag) ) {
+ if ( p == _in_req[input].end( ) ) {
+ if ( wrapped ) {
+ break;
+ }
+ // p is valid here because empty lists
+ // are skipped (above)
+ p = _in_req[input].begin( );
+ wrapped = true;
+ }
+
+ output = p->port;
+
+ // we know the output is free (above) and
+ // if the input is free, grant request
+ if ( _grants[output] == input ) {
+ // Accept
+ _inmatch[input] = output;
+ _outmatch[output] = input;
+
+ // Only update pointers if accepted during the 1st iteration
+ if ( iter == 0 ) {
+ _gptrs[output] = ( input + 1 ) % _inputs;
+ _aptrs[input] = ( output + 1 ) % _outputs;
+ }
+
+ break;
+ }
+
+ p++;
+ if ( p != _in_req[input].end( ) ) {
+ flag= (p->port < output_offset) ;
+ } else {
+ flag = true;
+ }
+ }
+ }
+ }
+
+#ifdef DEBUG_ISLIP
+ cout << "input match: ";
+ for ( int i = 0; i < _inputs; ++i ) {
+ cout << _inmatch[i] << " ";
+ }
+ cout << endl;
+
+ cout << "output match: ";
+ for ( int j = 0; j < _outputs; ++j ) {
+ cout << _outmatch[j] << " ";
+ }
+ cout << endl;
+#endif
+}
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