Basic support in ca65

src/ca65/pseudo.c

@@ -1924,6 +1924,14 @@ static void DoWarning (void)
 
 
 
+static void DoWeak (void)
+/* Declare a weak symbol */
+{
+    ExportImport (SymGlobal, ADDR_SIZE_DEFAULT, SF_WEAK);
+}
+
+
+
 static void DoWord (void)
 /* Define words */
 {
@@ -2121,6 +2129,7 @@ static CtrlDesc CtrlCmdTab [] = {
     { ccNone,           DoUnion         },
     { ccNone,           DoUnexpected    },      /* .VERSION */
     { ccNone,           DoWarning       },
+    { ccNone,           DoWeak          },
     { ccNone,           DoWord          },
     { ccNone,           DoUnexpected    },      /* .XMATCH */
     { ccNone,           DoZeropage      },

src/ca65/scanner.c

@@ -292,6 +292,7 @@ struct DotKeyword {
     { ".UNION",         TOK_UNION               },
     { ".VERSION",       TOK_VERSION             },
     { ".WARNING",       TOK_WARNING             },
+    { ".WEAK",          TOK_WEAK                },
     { ".WORD",          TOK_WORD                },
     { ".XMATCH",        TOK_XMATCH              },
     { ".XOR",           TOK_BOOLXOR             },

src/ca65/symentry.h

@@ -71,6 +71,7 @@ struct HLLDbgSym;
 #define SF_VAR          0x0080          /* Variable symbol */
 #define SF_FORCED       0x0100          /* Forced import, SF_IMPORT also set */
 #define SF_FIXED        0x0200          /* May not be trampoline */
+#define SF_WEAK         0x0400          /* Weak symbol */
 #define SF_MULTDEF      0x1000          /* Multiply defined symbol */
 #define SF_DEFINED      0x2000          /* Defined */
 #define SF_REFERENCED   0x4000          /* Referenced */

src/ca65/token.h

@@ -259,6 +259,7 @@ typedef enum token_t {
     TOK_UNION,
     TOK_VERSION,
     TOK_WARNING,
+    TOK_WEAK,
     TOK_WORD,
     TOK_XMATCH,
     TOK_ZEROPAGE,