crenshaw test: added division, multiply, reversed stack, avoid NEG

2 files changed, 39 insertions, 7 deletions

diff --git a/crenshaw/main.pas b/crenshaw/main.pas
index 677c496..12fec6e 100644
--- a/crenshaw/main.pas
+++ b/crenshaw/main.pas
@@ -72,18 +72,51 @@ begin;
 	WriteLn(s+':');
 end;
 
-procedure Term;
+procedure Factor;
 begin
 	EmitLn('mov eax, ' + GetNum);
 	EmitLn('push eax');
 end;
 
+procedure Multiply;
+begin
+	Match('*');
+	Factor;
+	EmitLn('pop ebx');
+	EmitLn('pop eax');
+	EmitLn('mul ebx');
+	EmitLn('push eax');
+end;
+
+procedure Divide;
+begin
+	Match('/');
+	Factor;
+	EmitLn('pop ebx');
+	EmitLn('pop eax');
+	EmitLn('div ebx');
+	EmitLn('push eax');
+end;
+
+procedure Term;
+begin
+	Factor;
+	while Look in ['*', '/'] do
+	begin
+		case Look of
+                        '*': Multiply;
+                        '/': Divide;
+                else Expected('* or /');
+                end;
+	end;
+end;
+
 procedure Add;
 begin;
 	Match('+');
 	Term;
-	Emitln('pop eax');
-	EmitLn('pop ebx');
+	Emitln('pop ebx');
+	EmitLn('pop eax');
 	EmitLn('add eax, ebx');
 	EmitLn('push eax');
 end;
@@ -92,10 +125,9 @@ procedure Subtract;
 begin;
 	Match('-');
 	Term;
-	EmitLn('pop eax');
 	EmitLn('pop ebx');
+	EmitLn('pop eax');
 	EmitLn('sub eax, ebx');
-	EmitLn('neg eax');
 	EmitLn('push eax');
 end;
 
@@ -107,7 +139,7 @@ begin
 		case Look of
 			'+': Add;
 			'-': Subtract;
-		else Expected('+/-');
+		else Expected('+ or -');
 		end;
 	end;
 end;
diff --git a/crenshaw/test.prog b/crenshaw/test.prog
index a490d4b..95b87fe 100644
--- a/crenshaw/test.prog
+++ b/crenshaw/test.prog
@@ -1,2 +1,2 @@
-4+2+5-8
+4+4*3/2-3