Add support for CPU models to execute the effective

address calculation and memory access portions separately.
Not currently used by any CPU models, but Kevin says he needs this.

Also clean up handling of execution tracing for memory accesses
(move it all into isa_desc and out of CPU models).

Got rid of some ancient unused code too.

arch/alpha/isa_desc:
    Add execute() methods to EAComp and MemAcc portions of memory
    access instructions, to allow CPU models to execute the effective
    address calculation and memory access portions separately.

    Requires the execution context to remember the effective address
    across the two invocations.  Added setEA() and getEA() methods to
    execution context to support this.  A model that does not use the
    split execution model can panic if these methods are called.

    Also added hook to call traceData->setAddr() after EA computation
    on any load or store operation.
arch/isa_parser.py:
    Call traceData->setData() on memory writes (stores).
cpu/simple_cpu/simple_cpu.cc:
    Get rid of unused code.
cpu/simple_cpu/simple_cpu.hh:
    Add (non-functional) setEA() and getEA() methods for new
    split memory access execution support.

--HG--
extra : convert_revision : bc2d2c758c4ca753812b9fa81f21038e55929ff0

2 files changed, 107 insertions, 70 deletions

diff --git a/arch/alpha/isa_desc b/arch/alpha/isa_desc
index 5154d78d1..5602a6ba6 100644
--- a/arch/alpha/isa_desc
+++ b/arch/alpha/isa_desc
@@ -790,48 +790,14 @@ output header {{
       protected:
 	/// Constructor
 	MemoryNoDisp(const char *mnem, MachInst _machInst, OpClass __opClass,
-		     StaticInstPtr<AlphaISA> _eaCompPtr,
-		     StaticInstPtr<AlphaISA> _memAccPtr)
+		     StaticInstPtr<AlphaISA> _eaCompPtr = nullStaticInstPtr,
+		     StaticInstPtr<AlphaISA> _memAccPtr = nullStaticInstPtr)
 	    : Memory(mnem, _machInst, __opClass, _eaCompPtr, _memAccPtr)
 	{
 	}
 
 	std::string generateDisassembly(Addr pc, const SymbolTable *symtab);
     };
-
-
-    /**
-     * Base class for "fake" effective-address computation
-     * instructions returnded by eaCompInst().
-     */
-    class EACompBase : public AlphaStaticInst
-    {
-      public:
-	/// Constructor
-	EACompBase(MachInst machInst)
-	    : AlphaStaticInst("(eacomp)", machInst, IntAluOp)
-	{
-	}
-
-	%(BasicExecDeclare)s
-    };
-
-    /**
-     * Base class for "fake" memory-access instructions returnded by
-     * memAccInst().
-     */
-    class MemAccBase : public AlphaStaticInst
-    {
-      public:
-	/// Constructor
-	MemAccBase(MachInst machInst, OpClass __opClass)
-	    : AlphaStaticInst("(memacc)", machInst, __opClass)
-	{
-	}
-
-	%(BasicExecDeclare)s
-    };
-
 }};
 
 
@@ -850,21 +816,6 @@ output decoder {{
     }
 }};
 
-output exec {{
-    Fault
-    EACompBase::execute(%(CPU_exec_context)s *, Trace::InstRecord *)
-    {
-	panic("attempt to execute eacomp");
-    }
-
-    Fault
-    MemAccBase::execute(%(CPU_exec_context)s *, Trace::InstRecord *)
-    {
-	panic("attempt to execute memacc");
-    }
-}};
-
-
 def format LoadAddress(code) {{
     iop = InstObjParams(name, Name, 'MemoryDisp32', CodeBlock(code))
     header_output = BasicDeclare.subst(iop)
@@ -885,21 +836,25 @@ def template LoadStoreDeclare {{
 	/**
 	 * "Fake" effective address computation class for "%(mnemonic)s".
 	 */
-	class EAComp : public EACompBase
+	class EAComp : public %(base_class)s
 	{
 	  public:
 	    /// Constructor
 	    EAComp(MachInst machInst);
+
+            %(BasicExecDeclare)s
 	};
 
 	/**
 	 * "Fake" memory access instruction class for "%(mnemonic)s".
 	 */
-	class MemAcc : public MemAccBase
+	class MemAcc : public %(base_class)s
 	{
 	  public:
 	    /// Constructor
 	    MemAcc(MachInst machInst);
+
+            %(BasicExecDeclare)s
 	};
 
       public:
@@ -912,14 +867,17 @@ def template LoadStoreDeclare {{
 }};
 
 def template LoadStoreConstructor {{
+    /** TODO: change op_class to AddrGenOp or something (requires
+     * creating new member of OpClass enum in op_class.hh, updating
+     * config files, etc.). */
     inline %(class_name)s::EAComp::EAComp(MachInst machInst)
-	: EACompBase(machInst)
+	: %(base_class)s("%(mnemonic)s (EAComp)", machInst, IntAluOp)
     {
 	%(ea_constructor)s;
     }
 
     inline %(class_name)s::MemAcc::MemAcc(MachInst machInst)
-	: MemAccBase(machInst, %(op_class)s)
+	: %(base_class)s("%(mnemonic)s (MemAcc)", machInst, %(op_class)s)
     {
 	%(memacc_constructor)s;
     }
@@ -932,6 +890,64 @@ def template LoadStoreConstructor {{
     }
 }};
 
+
+def template EACompExecute {{
+    Fault
+    %(class_name)s::EAComp::execute(%(CPU_exec_context)s *xc,
+				   Trace::InstRecord *traceData)
+    {
+	Addr EA;
+	Fault fault = No_Fault;
+
+	%(fp_enable_check)s;
+	%(op_decl)s;
+	%(op_rd)s;
+	%(code)s;
+
+	if (fault == No_Fault) {
+	    %(op_wb)s;
+	    xc->setEA(EA);
+	}
+
+	return fault;
+    }
+}};
+
+def template MemAccExecute {{
+    Fault
+    %(class_name)s::MemAcc::execute(%(CPU_exec_context)s *xc,
+				   Trace::InstRecord *traceData)
+    {
+	Addr EA;
+	Fault fault = No_Fault;
+
+	%(fp_enable_check)s;
+	%(op_decl)s;
+	%(op_nonmem_rd)s;
+	EA = xc->getEA();
+	
+	if (fault == No_Fault) {
+	    %(op_mem_rd)s;
+	    %(code)s;
+	}
+
+	if (fault == No_Fault) {
+	    %(op_mem_wb)s;
+	}
+
+	if (fault == No_Fault) {
+	    %(postacc_code)s;
+	}
+
+	if (fault == No_Fault) {
+	    %(op_nonmem_wb)s;
+	}
+
+	return fault;
+    }
+}};
+
+
 def template LoadStoreExecute {{
     Fault %(class_name)s::execute(%(CPU_exec_context)s *xc,
 				  Trace::InstRecord *traceData)
@@ -1022,18 +1038,33 @@ def LoadStoreBase(name, Name, ea_code, memacc_code, postacc_code = '',
 
     # Would be nice to autogenerate this list, but oh well.
     valid_mem_flags = ['LOCKED', 'NO_FAULT', 'EVICT_NEXT', 'PF_EXCLUSIVE']
-    inst_flags = []
-    mem_flags = []
-    for f in flags:
-	if f in valid_mem_flags:
-	    mem_flags.append(f)
-        else:
-            inst_flags.append(f)
+    mem_flags =  [f for f in flags if f in valid_mem_flags]
+    inst_flags = [f for f in flags if f not in valid_mem_flags]
+
+    # add hook to get effective addresses into execution trace output.
+    ea_code += '\nif (traceData) { traceData->setAddr(EA); }\n'
 
+    # generate code block objects
     ea_cblk = CodeBlock(ea_code)
     memacc_cblk = CodeBlock(memacc_code)
     postacc_cblk = CodeBlock(postacc_code)
 
+    # Some CPU models execute the memory operation as an atomic unit,
+    # while others want to separate them into an effective address
+    # computation and a memory access operation.  As a result, we need
+    # to generate three StaticInst objects.  Note that the latter two
+    # are nested inside the larger "atomic" one.
+
+    # generate InstObjParams for EAComp object
+    ea_iop = InstObjParams(name, Name, base_class, ea_cblk, inst_flags)
+    
+    # generate InstObjParams for MemAcc object
+    memacc_iop = InstObjParams(name, Name, base_class, memacc_cblk, inst_flags)
+    # in the split execution model, the MemAcc portion is responsible
+    # for the post-access code.
+    memacc_iop.postacc_code = postacc_cblk.code
+
+    # generate InstObjParams for unified execution
     cblk = CodeBlock(ea_code + memacc_code + postacc_code)
     iop = InstObjParams(name, Name, base_class, cblk, inst_flags)
 
@@ -1043,13 +1074,17 @@ def LoadStoreBase(name, Name, ea_code, memacc_code, postacc_code = '',
     iop.memacc_code = memacc_cblk.code
     iop.postacc_code = postacc_cblk.code
 
-    mem_flags = string.join(mem_flags, '|')
-    if mem_flags != '':
-        iop.constructor += '\n\tmemAccessFlags = ' + mem_flags + ';'
+    if mem_flags:
+        s = '\n\tmemAccessFlags = ' + string.join(mem_flags, '|') + ';'
+        iop.constructor += s
+        memacc_iop.constructor += s
 
     # (header_output, decoder_output, decode_block, exec_output)
     return (LoadStoreDeclare.subst(iop), LoadStoreConstructor.subst(iop),
-	    decode_template.subst(iop), exec_template.subst(iop))
+	    decode_template.subst(iop),
+            EACompExecute.subst(ea_iop)
+            + MemAccExecute.subst(memacc_iop)
+            + exec_template.subst(iop))
 }};
 
 
@@ -1460,8 +1495,8 @@ output header {{
 
 	/// Constructor
 	HwLoadStore(const char *mnem, MachInst _machInst, OpClass __opClass,
-		    StaticInstPtr<AlphaISA> _eaCompPtr,
-		    StaticInstPtr<AlphaISA> _memAccPtr);
+		    StaticInstPtr<AlphaISA> _eaCompPtr = nullStaticInstPtr,
+		    StaticInstPtr<AlphaISA> _memAccPtr = nullStaticInstPtr);
 
 	std::string generateDisassembly(Addr pc, const SymbolTable *symtab);
     };
diff --git a/arch/isa_parser.py b/arch/isa_parser.py
index c0b5131de..18e4b0a45 100755
--- a/arch/isa_parser.py
+++ b/arch/isa_parser.py
@@ -1210,10 +1210,12 @@ class MemOperandTraits(OperandTraits):
     def makeWrite(self, op_desc):
         (size, type, is_signed) = operandSizeMap[op_desc.eff_ext]
         eff_type = 'uint%d_t' % size
-        return 'fault = xc->write((%s&)%s, EA, %s_flags,' \
-               ' &%s_write_result);\n' \
+        wb = 'fault = xc->write((%s&)%s, EA, %s_flags, &%s_write_result);\n' \
                % (eff_type, op_desc.munged_name, op_desc.base_name,
                   op_desc.base_name)
+        wb += 'if (traceData) { traceData->setData(%s); }' % \
+              op_desc.munged_name
+        return wb
 
 class NPCOperandTraits(OperandTraits):
     def makeConstructor(self, op_desc):