+ added helper functions get_x86_string_op_si_param and get_x86_string_op_di_param

* use get_x86_string_op_si_param in the nasm writer

git-svn-id: trunk@37450 -

compiler/x86/agx86nsm.pas

@@ -989,16 +989,7 @@ interface
                else if is_x86_parameterized_string_instruction_op(fixed_opcode) then
                 begin
                   writer.AsmWrite(#9#9);
-                  case fixed_opcode of
-                    A_MOVS,A_OUTS:
-                      i:=1;
-                    A_CMPS,A_LODS:
-                      i:=0;
-                    A_SCAS,A_STOS,A_INS:
-                      i:=-1;
-                    else
-                      internalerror(2017101102);
-                  end;
+                  i:=get_x86_string_op_si_param(fixed_opcode);
                   if (i<>-1) and (taicpu(hp).oper[i]^.typ=top_ref) and
                      (taicpu(hp).oper[i]^.ref^.segment<>NR_NO) then
                     writer.AsmWrite(std_regname(taicpu(hp).oper[i]^.ref^.segment)+' ');

compiler/x86/cpubase.pas

@@ -325,6 +325,12 @@ uses
     function is_x86_parameterized_string_instruction_op(op: TAsmOp): boolean;
     function x86_param2paramless_string_op(op: TAsmOp): TAsmOp;
     function get_x86_string_op_size(op: TAsmOp): TOpSize;
+    { returns the 0-based operand number (intel syntax) of the ds:[si] param of
+      a x86 string instruction }
+    function get_x86_string_op_si_param(op: TAsmOp):shortint;
+    { returns the 0-based operand number (intel syntax) of the es:[di] param of
+      a x86 string instruction }
+    function get_x86_string_op_di_param(op: TAsmOp):shortint;
 
 {$ifdef i8086}
     { return whether we need to add an extra FWAIT instruction before the given
@@ -752,6 +758,36 @@ implementation
       end;
 
 
+    function get_x86_string_op_si_param(op: TAsmOp):shortint;
+      begin
+        case op of
+          A_MOVS,A_OUTS:
+            result:=1;
+          A_CMPS,A_LODS:
+            result:=0;
+          A_SCAS,A_STOS,A_INS:
+            result:=-1;
+          else
+            internalerror(2017101102);
+        end;
+      end;
+
+
+    function get_x86_string_op_di_param(op: TAsmOp):shortint;
+      begin
+        case op of
+          A_MOVS,A_SCAS,A_STOS,A_INS:
+            result:=0;
+          A_CMPS:
+            result:=1;
+          A_LODS,A_OUTS:
+            result:=-1;
+          else
+            internalerror(2017101202);
+        end;
+      end;
+
+
 {$ifdef i8086}
     function requires_fwait_on_8087(op: TAsmOp): boolean;
       begin