Changes between Version 15 and Version 16 of Writing Rules/RISC

Timestamp:

Jan 9, 2008, 8:52:45 PM (16 years ago)

Author:

alain

Comment:

--

Writing Rules/RISC

@@ -67 +67 @@
     RB  ,  // Read Byte Cached
     RZ ,   // Cache Line Invalidate 
-    RWU ,  // Read Word Uncached
-    RHU ,  // Read Half Uncached
-    RBU ,  // Read Byte Uncached
     WW ,  // Write Word
     WH ,  // Write Half
@@ -81 +78 @@
 This function is used by the wrapper to transmit to the ISS, the instruction to be executed ('''ins''' parameter). In case of exception (bus error), the '''error''' parameter is set.
 
- * '''inline void setRdata (bool error, uint32_t rdata)'''
-This function is used by the wrapper to transmit to the ISS, the read data ('''rdata''' parameter). In case of exception (bus error), the '''error''' parameter is set.
+ * '''inline void setDataResponse (bool error, uint32_t rdata)'''
+This function is used by the wrapper to transmit to the ISS, the response to the data request. In case of a read request, the  '''rdata''' parameter contains the read value. In case of exception (bus error), the '''error''' parameter is set. In any case, this function must reset the ISS data request.
 
  * '''inline void setWriteBerr ()''' 
@@ -180 +177 @@
 private :
 
-///////// Variables /////////
+///////////
 iss_t  m_iss ;
-bool  m_ins_asked ;
-bool  m_data_asked ;
 
 /////////////////////////
 void transition()
     {
+    bool ifrz = p_icache.frz.read() ;
+    bool ireq = p_icache.req.read() ;
+    bool iberr = p_icache.berr.read() ;
+
+    bool dfrz = p_dcache.frz.read() ;
+    bool dberr = p_dcache.berr.read() ;
+    bool dreq = p_dcache.req.read() ;
+
     if ( ! p_resetn.read() ) {
         m_iss.reset();    
@@ -193 +196 @@
     }
 
-    bool frozen = m_iss.isBusy();
-    
-    if ( m_ins_asked ) {
-        if ( p_icache.frz.read() ) frozen = true;
-        m_iss.setInstruction(p_icache.berr.read(), p_icache.ins.read())
+    if ( ireq ) {
+        m_iss.setInstruction( iberr, p_icache.ins.read())
     }
 
-    if ( m_data_asked ) {
-        if ( p_dcache.frz.read() ) frozen = true;
-        m_iss.setRdata(p_dcache.berr.read(), p_dcache.rdata.read());
-    }
-
-    if ( frozen ) {     //  Processor frozen or busy
+    if ( dberr && ( !dreq || dfrz ) ) {
+        m_iss.setWriteBerr() ;
+    } else if ( dreq ) {
+        m_iss.setDataResponse( dberr, p_dcache.rdata.read() ) ;
+    } 
+
+    if ( m_iss.isBusy() || ifrz || dfrz ) {     //  Processor frozen or busy
         m_iss.nullStep();
-    } else {                    // Execute one instruction:
+    } else {                        // Execute one instruction:
         m_iss.step();
     }
@@ -215 +216 @@
     for ( size_t i=0; i<(size_t)iss_t::n_irq; i++ )  { if (p_irq[i].read()) irqword |= (1<<i); }
     m_iss.setIrq(irqword);
-
-    // report asynchronous bus error
-    if ( p_dcache.berr.read() ) m_iss.setWriteBerr() ;
 
     } // end transition()