Add cc65 artifacts to repo for now

cc65/asminc/cbm.mac

@@ -0,0 +1,56 @@
+; Convert characters to screen codes
+
+; Macro that converts one character.
+; scrbyte() can be used as an instruction operand
+.define scrbyte(code)   (<(.strat ("h@dbdlhh", code >> 5) << 4) ^ code)
+
+; Helper macro that stores one character
+.macro _scrcode char
+        .if (char < 256)
+                .byte   scrbyte {char}
+        .else
+                .error  "scrcode: Character constant out of range"
+        .endif
+.endmacro
+
+.macro  scrcode arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9
+
+        ; Bail out if next argument is empty
+        .if     .blank ({arg1})
+                .exitmacro
+        .endif
+
+        ; Check for a string
+        .if     .match ({arg1}, "")
+
+                ; Walk over all string chars
+                .repeat .strlen (arg1), i
+                        _scrcode        {.strat (arg1, i)}
+                .endrepeat
+
+        ; Check for a number
+        .elseif .match (.left (1, {arg1}), 0)
+
+                ; Just output the number
+                _scrcode        arg1
+
+        ; Check for a character
+        .elseif .match (.left (1, {arg1}), 'a')
+
+                ; Just output the character
+                _scrcode        arg1
+
+        ; Check for an identifier
+        .elseif .match (.left (1, {arg1}), identifier)
+
+                ; Just output the identifier
+                _scrcode        arg1
+
+        ; Anything else is an error
+        .else
+                .error  "scrcode: invalid argument type"
+        .endif
+
+        ; Call the macro recursively with the remaining args
+        scrcode arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9
+.endmacro