From 5c55cc374815fb99ef43f55b8d2332d3798efc59 Mon Sep 17 00:00:00 2001
From: Martin Griffin <martinrgriffin@gmail.com>
Date: Wed, 21 Aug 2024 07:50:41 +0100
Subject: [PATCH] [preproc] support arbitrary expressions in enums

---
 tools/preproc/asm_file.cpp | 26 ++++++++++++++++++++++----
 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/tools/preproc/asm_file.cpp b/tools/preproc/asm_file.cpp
index ca8b8cc4ae..36b6c7ed06 100644
--- a/tools/preproc/asm_file.cpp
+++ b/tools/preproc/asm_file.cpp
@@ -520,6 +520,7 @@ bool AsmFile::ParseEnum()
     long currentHeaderLine = SkipWhitespaceAndEol();
     std::string enumName = ReadIdentifier();
     currentHeaderLine += SkipWhitespaceAndEol();
+    std::string enumBase = "0";
     long enumCounter = 0;
     long symbolCount = 0;
 
@@ -542,11 +543,28 @@ bool AsmFile::ParseEnum()
             if (m_buffer[m_pos] == '=')
             {
                 m_pos++;
-                currentHeaderLine += SkipWhitespaceAndEol();
-                enumCounter = ReadInteger(headerFilename, currentHeaderLine);
-                currentHeaderLine += SkipWhitespaceAndEol();
+                SkipWhitespace();
+                enumBase.clear();
+                for (;;)
+                {
+                    if (m_pos == m_size)
+                        RaiseError("unexpected EOF");
+                    if (m_buffer[m_pos] == ',')
+                        break;
+                    if (m_buffer[m_pos] == '\n')
+                    {
+                        currentHeaderLine++;
+                        enumBase.push_back(' ');
+                    }
+                    else
+                    {
+                        enumBase.push_back(m_buffer[m_pos]);
+                    }
+                    m_pos++;
+                }
+                enumCounter = 0;
             }
-            std::printf(".equiv %s, %ld\n", currentIdentName.c_str(), enumCounter);
+            std::printf(".equiv %s, (%s) + %ld\n", currentIdentName.c_str(), enumBase.c_str(), enumCounter);
             enumCounter++;
             symbolCount++;
         }