Make unterminated strings error and range warnings better

Unterminated strings were mentioned in #29, I decided to make them an
error because it was slightly technically easier. Also I don't know of
any riscv assembler which allows unterminated strings.

The range warnings for .byte and .half were improved to not warn on
values the fit in an unsigned byte/half and to say exactly how the value
is truncated. Now it matches how gcc handles it. This was mentioned in

rars/assembler/Assembler.java

@@ -909,8 +909,8 @@ private void storeInteger(Token token, Directives directive, ErrorList errors) {
 
             if (DataTypes.outOfRange(directive, fullvalue)) {
                 errors.add(new ErrorMessage(ErrorMessage.WARNING, token.getSourceProgram(), token.getSourceLine(),
-                        token.getStartPos(), "\"" + token.getValue()
-                        + "\" is out-of-range for a signed value and possibly truncated"));
+                        token.getStartPos(), "value " + Binary.intToHexString(fullvalue)
+                        + " is out-of-range and truncated to " + Binary.intToHexString(value)));
             }
             if (this.inDataSegment) {
                 writeToDataSegment(value, lengthInBytes, token, errors);

rars/assembler/DataTypes.java

@@ -143,8 +143,9 @@ else if (direct == Directives.BYTE)
      * by the given directive (.word, .half, .byte), <tt>false</tt> otherwise.
      **/
     public static boolean outOfRange(Directives direct, int value) {
-        return (direct == Directives.HALF && (value < MIN_HALF_VALUE || value > MAX_HALF_VALUE)) ||
-                (direct == Directives.BYTE && (value < MIN_BYTE_VALUE || value > MAX_BYTE_VALUE));
+        // Hex values used here rather than constants because there aren't constants for unsigned max
+        return (direct == Directives.HALF && (value < MIN_HALF_VALUE || value > 0xFFFF)) ||
+                (direct == Directives.BYTE && (value < MIN_BYTE_VALUE || value > 0xFF));
     }
 
     /**

rars/assembler/Tokenizer.java

@@ -436,6 +436,10 @@ public TokenList tokenizeLine(RISCVprogram program, int lineNum, String theLine,
             linePos++;
         }  // while
         if (tokenPos > 0) {
+            if(insideQuotedString){
+                errors.add(new ErrorMessage(program, lineNum, tokenStartPos,
+                        "String is not terminated."));
+            }
             this.processCandidateToken(token, program, lineNum, theLine, tokenPos, tokenStartPos, result);
             tokenPos = 0;
         }