OMF format: Select 16/32 bit based on SEGHEAD

Ghidra/Features/Base/src/main/java/ghidra/app/util/bin/format/omf/OmfCommentRecord.java

@@ -27,6 +27,10 @@ public class OmfCommentRecord extends OmfRecord {
 	public static final byte COMMENT_CLASS_LIBMOD = (byte) 0xA3;
 	// Default library cmd
 	public static final byte COMMENT_CLASS_DEFAULT_LIBRARY = (byte) 0x9F;
+	// Watcom compile parameters
+	public static final byte COMMENT_CLASS_WATCOM_SETTINGS = (byte) 0x9b;
+	// Microsoft compile parameters
+	public static final byte COMMENT_CLASS_MICROSOFT_SETTINGS = (byte) 0x9d;
 
 	private byte commentType;
 	private byte commentClass;

Ghidra/Features/Base/src/main/java/ghidra/app/util/bin/format/omf/OmfFileHeader.java

@@ -37,6 +37,7 @@ public class OmfFileHeader extends OmfRecord {
 	private ArrayList<OmfFixupRecord> fixup = new ArrayList<OmfFixupRecord>();
 	private ArrayList<OmfSegmentHeader> extraSeg = null;		// Holds implied segments that don't have official header record
 	//	private OmfModuleEnd endModule = null;
+	private boolean format16bit;
 
 	public OmfFileHeader(BinaryReader reader) throws IOException {
 		readRecordHeader(reader);
@@ -65,7 +66,7 @@ public class OmfFileHeader extends OmfRecord {
 	 * @return the string identifying the architecture this object was compiled for
 	 */
 	public String getMachineName() {
-		return "i386";			// This is the only possibility
+		return format16bit ? "16bit" : "32bit";
 	}
 
 	/**
@@ -250,13 +251,13 @@ public class OmfFileHeader extends OmfRecord {
 	 * Scan the object file, for the main header and comment records. Other records are parsed but not saved
 	 * @param reader is the byte stream
 	 * @param monitor is checked for cancellation
-	 * @param initialCommentsOnly  is true if we only want to scan the header and the initial comments,
+	 * @param fastscan is true if we only want to scan the header until first seghead,
 	 * @return the header record
 	 * @throws IOException for problems reading program data
 	 * @throws OmfException for malformed records
 	 */
 	public static OmfFileHeader scan(BinaryReader reader, TaskMonitor monitor,
-			boolean initialCommentsOnly) throws IOException, OmfException {
+			boolean fastscan) throws IOException, OmfException {
 		OmfRecord record = OmfRecord.readRecord(reader);
 		if (!(record instanceof OmfFileHeader)) {
 			throw new OmfException("Object file does not start with proper header");
@@ -274,16 +275,26 @@ public class OmfFileHeader extends OmfRecord {
 			}
 
 			if (record instanceof OmfCommentRecord comment) {
-				byte commentClass = comment.getCommentClass();
+				switch(comment.getCommentClass()) {
-				if (commentClass == OmfCommentRecord.COMMENT_CLASS_TRANSLATOR) {
+				case OmfCommentRecord.COMMENT_CLASS_TRANSLATOR:
 					header.translator = comment.getValue();
-				}
+					break;
-				else if (commentClass == OmfCommentRecord.COMMENT_CLASS_LIBMOD) {
+				case OmfCommentRecord.COMMENT_CLASS_LIBMOD:
 					header.libModuleName = comment.getValue();
+					break;
+				case OmfCommentRecord.COMMENT_CLASS_WATCOM_SETTINGS:
+					header.translator = "Watcom";
+					break;
+				case OmfCommentRecord.COMMENT_CLASS_MICROSOFT_SETTINGS:
+					header.translator = "Microsoft";
+					break;
 				}
 			}
-			else if (initialCommentsOnly) {
+			else if (record instanceof OmfSegmentHeader head) {
-				break;
+				header.format16bit = head.is16Bit();
+				if(fastscan) {
+					break;
+				}
 			}
 		}
 		return header;

Ghidra/Features/Base/src/main/java/ghidra/app/util/bin/format/omf/OmfSegmentHeader.java

@@ -206,6 +206,13 @@ public class OmfSegmentHeader extends OmfRecord {
 		return (segAttr >> 2) & 0x7;
 	}
 
+	/**
+	 * @return if 16 or 32 bit segments are used
+	 */
+	public boolean is16Bit() {
+		return (segAttr & 1) == 0;
+	}
+
 	/**
 	 * @return true if this block uses filler other than zero bytes
 	 */

Ghidra/Features/Base/src/main/java/ghidra/app/util/opinion/OmfLoader.java

@@ -70,6 +70,12 @@ public class OmfLoader extends AbstractProgramWrapperLoader {
 		if (record.startsWith("CodeGear")) {
 			return "codegearcpp";
 		}
+		if (record.equals("MS C")) {
+			return "windows";
+		}
+		if(record.startsWith("Watcom")) {
+			return "watcom";
+		}
 		return null;
 	}
 

Ghidra/Processors/x86/data/languages/x86.opinion

@@ -65,17 +65,17 @@
     </constraint>
     <constraint loader="Relocatable Object Module Format (OMF)">
       <constraint compilerSpecID="windows">
-        <constraint primary="i386" processor="x86"          endian="little" size="32" />
+        <constraint primary="32bit" processor="x86"          endian="little" size="32" />
       </constraint>
       <constraint compilerSpecID="default">
-        <constraint primary="i386" processor="x86"          endian="little" size="16" />
+        <constraint primary="16bit" processor="x86"          endian="little" size="16" />
       </constraint>
       <constraint compilerSpecID="borlandcpp">
-        <constraint primary="i386" secondary="borlandcpp" processor="x86"        endian="little" size="32" />
+        <constraint primary="32bit" secondary="borlandcpp" processor="x86"        endian="little" size="32" />
-        <constraint primary="i386" secondary="codegearcpp" processor="x86"       endian="little" size="32" />
+        <constraint primary="32bit" secondary="codegearcpp" processor="x86"       endian="little" size="32" />
       </constraint>
       <constraint compilerSpecID="borlanddelphi">
-        <constraint primary="i386" secondary="borlanddelphi" processor="x86"     endian="little" size="32" />
+        <constraint primary="32bit" secondary="borlanddelphi" processor="x86"     endian="little" size="32" />
       </constraint>
     </constraint>
 </opinions>