Changeset 86 for trunk/Target/UTargetFPC.pas

Timestamp:

Aug 29, 2017, 5:12:18 PM (7 years ago)

Author:

chronos

Message:

• Added: New optimization using relative indexes to eliminate lots of pointer inc/dec operations.
• Added: New command "multiply" extended command to replace while loops used for cell multiplication. Also added related optimization.

File:

• trunk/Target/UTargetFPC.pas (modified) (4 diffs)

trunk/Target/UTargetFPC.pas

@@ -14 +14 @@
   TTargetFPC = class(TBFTarget)
   private
+    function GetMemoryCell: string;
   public
     constructor Create; override;
@@ -43 +44 @@
 end;
 
+function TTargetFPC.GetMemoryCell: string;
+begin
+  Result := 'Memory[Pos';
+  if FProgram[FProgramIndex].RelIndex > 0 then
+    Result := Result + ' + ' + IntToStr(FProgram[FProgramIndex].RelIndex)
+  else if FProgram[FProgramIndex].RelIndex < 0 then
+    Result := Result + ' - ' + IntToStr(Abs(FProgram[FProgramIndex].RelIndex));
+  Result := Result + ']';
+end;
+
 procedure TTargetFPC.Compile;
 begin
@@ -50 +61 @@
 
   AddLine('program ' + ProgramName + ';');
-  AddLine('');
   AddLine('var');
   AddLine('  Memory: array[0..30000] of Byte;');
@@ -63 +73 @@
       cmPointerInc: AddLine('Inc(Pos, ' + IntToStr(FProgram[FProgramIndex].Parameter) + ');');
       cmPointerDec: AddLine('Dec(Pos, ' + IntToStr(FProgram[FProgramIndex].Parameter) + ');');
-      cmInc: AddLine('Memory[Pos] := Memory[Pos] + ' + IntToStr(FProgram[FProgramIndex].Parameter) + ';');
-      cmDec: AddLine('Memory[Pos] := Memory[Pos] - ' + IntToStr(FProgram[FProgramIndex].Parameter) + ';');
-      cmSet: AddLine('Memory[Pos] := ' + IntToStr(FProgram[FProgramIndex].Parameter) + ';');
-      cmOutput: AddLine('Write(Chr(Memory[Pos]));');
-      cmInput: AddLine('Read(ReadChar); Memory[Pos] := Ord(ReadChar);');
+      cmInc: AddLine(GetMemoryCell + ' := ' + GetMemoryCell + ' + ' + IntToStr(FProgram[FProgramIndex].Parameter) + ';');
+      cmDec: AddLine(GetMemoryCell + ' := ' + GetMemoryCell + ' - ' + IntToStr(FProgram[FProgramIndex].Parameter) + ';');
+      cmSet: AddLine(GetMemoryCell + ' := ' + IntToStr(FProgram[FProgramIndex].Parameter) + ';');
+      cmMultipy: AddLine(GetMemoryCell + ' := ' + GetMemoryCell + ' + Memory[Pos] * ' + IntToStr(FProgram[FProgramIndex].Parameter) + ';');
+      cmOutput: AddLine('Write(Chr(' + GetMemoryCell + '));');
+      cmInput: AddLine('Read(ReadChar); ' + GetMemoryCell + ' := Ord(ReadChar);');
       cmLoopStart: begin
-        AddLine('while Memory[Pos] <> 0 do begin');
+        AddLine('while ' + GetMemoryCell + ' <> 0 do begin');
         Inc(Indent);
       end;