From d6b55db381d718f242721b5868450143c8a74dc3 Mon Sep 17 00:00:00 2001
From: n loewen <nick@nloewen.com>
Date: Thu, 24 Aug 2023 15:26:37 +0100
Subject: [PATCH] assembler - Add feature: allow use of `*` with a numeric
 offset

---
 assembler.js | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/assembler.js b/assembler.js
index 378d3c0..44b52b1 100644
--- a/assembler.js
+++ b/assembler.js
@@ -53,6 +53,7 @@ const mnemonics2opcodes = {
  * @property {SourceLineType} type - line type
  * @property {string} [operation] - For code: the first non-whitespace chunk
  * @property {string} [argument] - For code: the second non-whitespace chunk, if there is one
+ * @property {string} [extraArgument] - For code: the third non-whitespace chunk, if there is one
  **/
 
 /**
@@ -87,13 +88,20 @@ function preparseSourceCode(source) {
     dbg(1, ``);
 
     if (info.type === 'code') {
-      const op_arg_array = info.sanitized.split(/\s+/); // split line into an array of [op, arg]
+      const op_arg_array = info.sanitized.split(/\s+/); // split line into an array of [op, arg, extra_arg]
       if (op_arg_array[0] !== 'undefined') {
         info.operation = op_arg_array[0];
       }
       if (op_arg_array.length === 2) {
         info.argument = op_arg_array[1];
       }
+      if (op_arg_array.length === 3) {
+        info.argument = op_arg_array[1];
+        info.extraArgument = op_arg_array[2];
+      }
+      if (op_arg_array.length > 3) {
+        console.error('Error on line ${info.number}: Too many arguments');
+      }
     }
     return info;
   });
@@ -285,7 +293,11 @@ function decodeInstructions(source) {
       // Operands - Handle references to the Instruction Pointer
       if (line.argument === ASM_IP_LABEL) {
         dbg(1, `  References current IP - ${IP}`);
-        decodedArg = IP;
+        if (typeof line.extraArgument === 'undefined') {
+          decodedArg = IP;
+        } else {
+          decodedArg = IP + decodeNumericOp(line.extraArgument);
+        }
       }
 
       // Operands - Handle references to constants