From 57525d5464ccd2ae273e6f1e636ccf38269b720e Mon Sep 17 00:00:00 2001
From: Kelvin Sherlock <ksherlock@gmail.com>
Date: Sun, 15 Dec 2019 13:05:41 -0500
Subject: [PATCH] EXT support.  8/16+ added EXT as an operand to import an
 absolute linker value into the local symbol table.

---
 link.cpp | 12 ++++++++++++
 link.h   |  4 ++++
 2 files changed, 16 insertions(+)

diff --git a/link.cpp b/link.cpp
index d050194..d350467 100644
--- a/link.cpp
+++ b/link.cpp
@@ -932,6 +932,18 @@ void evaluate(label_t label, opcode_t opcode, const char *cursor) {
 			define(label, number_operand(cursor, local_symbol_table), LBL_GEQ);
 			break;
 
+		case OP_EXT: {
+			/* no label is a no-op. */
+			if (label.empty()) break;
+
+			/* otherwise, it imports an absolute label into the local symbol table */
+			auto e = find_symbol(label, false);
+			if (!e || !e->absolute) throw std::runtime_error("Bad address");
+			define(label, e->value, LBL_EXT);
+
+			break;
+		}
+
 		case OP_SEG: {
 			/* OMF object file linker - set the object file seg name */
 			std::string name = label_operand(cursor);
diff --git a/link.h b/link.h
index 298acfa..1e95937 100644
--- a/link.h
+++ b/link.h
@@ -36,6 +36,8 @@ c = command file
 	POS		n	y	n
 	LEN		n	y	n
 
+	EXT		n	n	y << imports from linker to command
+
 */
 enum {
 	LBL_EQU = (1 << 0),
@@ -45,6 +47,8 @@ enum {
 	LBL_EQ  = (1 << 2),
 	LBL_POS = (1 << 1),
 	LBL_LEN = (1 << 1),
+
+	LBL_EXT = (1 << 2)
 };
 
 void process_script(const char *argv);