# HG changeset patch
# User William Astle <lost@l-w.ca>
# Date 1694154760 21600
# Node ID 928c033c0cd0f11681d77fb274a47a2820d5cc05
# Parent  bbc600db50165002ac9038d872bbcee1ee089111
Allow MOD directive to accept only the standard base header parameters

There are cases where only the standard OS9 module header fields are to be
provided. This could be, for instance, in the case of a nonstandard user
type module. So allow the execution offset and data size fields to be
omitted entirely and handle the module length correctly as well.

diff -r bbc600db5016 -r 928c033c0cd0 lwasm/os9.c
--- a/lwasm/os9.c	Sun Jul 23 17:07:58 2023 -0600
+++ b/lwasm/os9.c	Fri Sep 08 00:32:40 2023 -0600
@@ -82,7 +82,7 @@
 		return;
 	}
 
-	// parse 6 expressions...
+	// parse 6 (or 4) expressions...
 	for (i = 0; i < 5; i++)
 	{
 		e = lwasm_parse_expr(as, p);
@@ -96,12 +96,19 @@
 
 		if (**p != ',')
 		{
+			if (i == 3)
+			{
+				// we don't have the extra items; flag it and don't bother
+				// with them later; goto is to short circuit the rest of
+				// the expression parsing
+				l -> lint = 4;
+				goto doneexpr;
+			}
 			lwasm_register_error(as, l, E_OPERAND_BAD);
 			return;
 		}
 		(*p)++;
 	}
-
 	e = lwasm_parse_expr(as, p);
 	if (!e)
 	{
@@ -109,7 +116,9 @@
 		return;
 	}
 	lwasm_save_expr(l, 5, e);
+	l -> lint = 6;
 
+doneexpr:
 	l -> inmod = 1;
 	
 	// we have an implicit ORG 0 with "mod"
@@ -123,7 +132,7 @@
 	// init crc
 	as -> inmod = 1;
 	
-	l -> len = 13;
+	l -> len = (i == 6) ? 13 : 9;
 }
 
 EMITFUNC(pseudo_emit_mod)
@@ -157,15 +166,18 @@
 		^ lw_expr_intval(e3) ^ lw_expr_intval(e4));
 	lwasm_emit(l, csum);
 
-	// module type specific output
-	// note that these are handled the same for all so
-	// there need not be any special casing
-	
-	// exec offset or fmgr name offset
-	lwasm_emitexpr(l, lwasm_fetch_expr(l, 4), 2);
-	
-	// data size or drvr name offset
-	lwasm_emitexpr(l, lwasm_fetch_expr(l, 5), 2);
+	if (l -> lint == 6)
+	{
+		// module type specific output, if provided
+		// note that these are handled the same for all so
+		// there need not be any special casing
+
+		// exec offset or fmgr name offset
+		lwasm_emitexpr(l, lwasm_fetch_expr(l, 4), 2);
+
+		// data size or drvr name offset
+		lwasm_emitexpr(l, lwasm_fetch_expr(l, 5), 2);
+	}
 }
 
 PARSEFUNC(pseudo_parse_emod)