From: Alan Cox <alan@linux.intel.com>
Date: Sun, 29 Oct 2017 16:34:19 +0000 (+0000)
Subject: as: fix handling of unknown symbols in subtraction
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=10bb07d5864315250beeb6bfaa726b4011ef2b55;p=FUZIX.git

as: fix handling of unknown symbols in subtraction

Propogate segment requirements to object module for linker to fault
---

diff --git a/Applications/MWC/cmd/asz80/as3.c b/Applications/MWC/cmd/asz80/as3.c
index cedc59a1..8125e050 100644
--- a/Applications/MWC/cmd/asz80/as3.c
+++ b/Applications/MWC/cmd/asz80/as3.c
@@ -89,10 +89,23 @@ static void chksegment(ADDR *left, ADDR *right, int op)
 		return;
 	}
 	/* Subtraction within segment produces an absolute */
-	if (left->a_segment == right->a_segment && op == '-') {
-		left->a_segment = ABSOLUTE;
-		left->a_sym = NULL;
-		return;
+	if (op == '-') {
+		/* Unknown symbols may get segment forced as a result */
+		if (left->a_segment == -1) {
+			left->a_segment = right->a_segment;
+			if (left->a_sym)
+				left->a_sym->s_segment = left->a_segment;
+		}
+		if (right->a_segment == -1) {
+			right->a_segment = left->a_segment;
+			if (right->a_sym)
+				right->a_sym->s_segment = right->a_segment;
+		}
+		if (left->a_segment == right->a_segment && op == '-') {
+			left->a_segment = ABSOLUTE;
+			left->a_sym = NULL;
+			return;
+		}
 	}
 	left->a_sym = NULL;
 	aerr(MUST_BE_ABSOLUTE);
@@ -204,7 +217,7 @@ void expr2(ADDR *ap)
 		expr3(ap, c);
 		return;
 	}
-	if (isalpha(c)) {
+	if (isalpha(c) || c == '_') {
 		getid(id, c);
 		if ((sp=lookup(id, uhash, 0)) == NULL
 		&&  (sp=lookup(id, phash, 0)) == NULL)
diff --git a/Applications/MWC/cmd/asz80/as4.c b/Applications/MWC/cmd/asz80/as4.c
index de60662d..5e528c2b 100644
--- a/Applications/MWC/cmd/asz80/as4.c
+++ b/Applications/MWC/cmd/asz80/as4.c
@@ -137,8 +137,9 @@ static void putsymbol(SYM *s, FILE *ofp)
 	else {
 		if (s->s_type & TPUBLIC)
 			flag |= S_PUBLIC;
-		flag |= s->s_segment;
 	}
+	/* 0 absolute, 1-n segments, -1 don't care */
+	flag |= (s->s_segment & S_SEGMENT);
 	putc(flag, ofp);
 	fwrite(s->s_id, 16, 1, ofp);
 	putc(s->s_value, ofp);