src/main/wacc/backend/RuntimeErrors.scala

@@ -12,5 +12,19 @@ case class RuntimeError(strLabel: String, errStr: String, errLabel: String) {
 }
 
 object RuntimeErrors {
-  val zeroDivError = RuntimeError(".L._errDivZero_str0", "fatal error: division or modulo by zero", ".L._errDivZero")
+  val zeroDivError = RuntimeError(
+    ".L._errDivZero_str0",
+    "fatal error: division or modulo by zero",
+    ".L._errDivZero"
+  )
+  val badChrError = RuntimeError(
+    ".L._errBadChr_str0",
+    "fatal error: int %d is not ascii character 0-127",
+    ".L._errBadChr"
+  )
+  val nullPtrError = RuntimeError(
+    ".L._errNullPtr_str0",
+    "fatal error: null pair dereferenced or freed",
+    ".L._errNullPtr"
+  )
 }

src/main/wacc/backend/asmGenerator.scala

@@ -5,7 +5,6 @@ import cats.data.Chain
 import cats.syntax.foldable._
 import wacc.RuntimeErrors._
 
-
 object asmGenerator {
   import microWacc._
   import assemblyIR._
@@ -65,6 +64,8 @@ object asmGenerator {
         Directive.Asciz(str.escaped)
       )
     } ++ zeroDivError.stringDef
+      ++ badChrError.stringDef
+      ++ nullPtrError.stringDef // TODO COLLATE TO ONE LIST INSTANCE
 
     Chain(
       Directive.IntelSyntax,
@@ -145,7 +146,16 @@ object asmGenerator {
       // Out of memory check is optional
     )
 
-    chain ++= wrapBuiltinFunc(labelGenerator.getLabel(Builtin.Free), Chain.empty)
+    chain ++= wrapBuiltinFunc(
+      labelGenerator.getLabel(Builtin.Free),
+      Chain(
+        stackAlign,
+        Move(RDI, RAX),
+        Compare(RDI, ImmediateVal(0)),
+        Jump(LabelArg(nullPtrError.errLabel), Cond.Equal),
+        assemblyIR.Call(CLibFunc.Free)
+      )
+    )
 
     chain ++= wrapBuiltinFunc(
       labelGenerator.getLabel(Builtin.Read),
@@ -170,6 +180,25 @@ object asmGenerator {
       assemblyIR.Call(CLibFunc.Exit)
     )
 
+    chain ++= Chain(
+      LabelDef(badChrError.errLabel),
+      Pop(RSI),
+      stackAlign,
+      Load(RDI, IndexAddress(RIP, LabelArg(badChrError.strLabel))),
+      assemblyIR.Call(CLibFunc.PrintF),
+      Move(RDI, ImmediateVal(-1)),
+      assemblyIR.Call(CLibFunc.Exit)
+    )
+
+    chain ++= Chain(
+      LabelDef(nullPtrError.errLabel),
+      stackAlign,
+      Load(RDI, IndexAddress(RIP, LabelArg(nullPtrError.strLabel))),
+      assemblyIR.Call(CLibFunc.PrintF),
+      Move(RDI, ImmediateVal(255)),
+      assemblyIR.Call(CLibFunc.Exit)
+    )
+
     chain
   }
 
@@ -305,7 +334,12 @@ object asmGenerator {
       case UnaryOp(x, op) =>
         chain ++= evalExprOntoStack(x)
         op match {
-          case UnaryOperator.Chr | UnaryOperator.Ord => // No op needed
+          case UnaryOperator.Chr =>
+            chain += Move(EAX, stack.head)
+            chain += And(EAX, ImmediateVal(-128))
+            chain += Compare(EAX, ImmediateVal(0))
+            chain += Jump(LabelArg(badChrError.errLabel), Cond.NotEqual)
+          case UnaryOperator.Ord => // No op needed
           case UnaryOperator.Len =>
             chain += stack.pop(RAX)
             chain += Move(EAX, MemLocation(RAX, D32))
@@ -343,6 +377,8 @@ object asmGenerator {
             chain += stack.push(destX.size, RAX)
 
           case BinaryOperator.Mod =>
+            chain += Compare(stack.head, ImmediateVal(0))
+            chain += Jump(LabelArg(zeroDivError.errLabel), Cond.Equal)
             chain += CDQ()
             chain += Divide(stack.head)
             chain += stack.drop()