diff --git a/README b/README
index 6ad500e..37f2f9c 100644
--- a/README
+++ b/README
@@ -150,6 +150,11 @@ Options:
                     This also works for extracting an object library
                     (.OLB) file.
 
+    -rsx            Tells macro11 to generate rsx style object files.
+                    This is the default.
+
+    -rt11           Tells macro11 to generate rt11 style object files.
+
     Various options starting with -y enable extensions:
 
     -ysl <num>      Allow longer symbols up to the given length.
diff --git a/macro11.c b/macro11.c
index f21de1d..d748ee6 100644
--- a/macro11.c
+++ b/macro11.c
@@ -55,7 +55,6 @@ DAMAGE.
 
 #define stricmp strcasecmp
 
-
 /* enable_tf is called by command argument parsing to enable and
    disable named options. */
 
@@ -344,6 +343,10 @@ int main(
                 list_pass_0++;
             } else if (!stricmp(cp, "yd")) {
                 enabl_debug++;
+            } else if (!stricmp(cp, "rt11")) {
+                rt11 = 1;
+            } else if (!stricmp(cp, "rsx")) {
+                rt11 = 0;
             } else {
                 fprintf(stderr, "Unknown option %s\n", argv[arg]);
                 print_help();
diff --git a/object.c b/object.c
index 061117c..b6cbb27 100644
--- a/object.c
+++ b/object.c
@@ -47,6 +47,8 @@ DAMAGE.
 #include "rad50.h"
 #include "object.h"
 
+int rt11 = 0;
+
 /*
   writerec writes "formatted binary records."
   Each is preceeded by any number of 0 bytes, begins with a 1,0 pair,
@@ -66,24 +68,27 @@ static int writerec(
     int             chksum;     /* Checksum is negative sum of all
                                    bytes including header and length */
     int             i;
-#if RT11
-    unsigned        hdrlen = len + 4;
-#else
-    unsigned        hdrlen = len;
-#endif
+    unsigned        hdrlen;
+
+    if (rt11) {
+        hdrlen = len + 4;
+    } else {
+        hdrlen = len;
+    }
 
     if (fp == NULL)
         return 1;                      /* Silently ignore this attempt to write. */
 
     chksum = 0;
-#if RT11
-    if (fputc(FBR_LEAD1, fp) == EOF)   /* All recs begin with 1,0 */
-        return 0;
-    chksum -= FBR_LEAD1;
-    if (fputc(FBR_LEAD2, fp) == EOF)
-        return 0;
-    chksum -= FBR_LEAD2;
-#endif /* RT11 */
+
+    if (rt11) {
+        if (fputc(FBR_LEAD1, fp) == EOF)   /* All recs begin with 1,0 */
+            return 0;
+        chksum -= FBR_LEAD1;
+        if (fputc(FBR_LEAD2, fp) == EOF)
+            return 0;
+        chksum -= FBR_LEAD2;
+    } /* RT11 */
 
     i = hdrlen & 0xff;                 /* length, lsb */
     chksum -= i;
@@ -106,13 +111,13 @@ static int writerec(
 
     chksum &= 0xff;
 
-#if RT11
-    fputc(chksum, fp);                 /* Followed by the checksum byte */
-#else /* RT11 */
-    if (hdrlen & 1) {
-        fputc(0, fp);                  /* Padding to even boundary */
+    if (rt11) {
+        fputc(chksum, fp);             /* Followed by the checksum byte */
+    } else { /* RT11 */
+        if (hdrlen & 1) {
+            fputc(0, fp);              /* Padding to even boundary */
     }
-#endif /* RT11 */
+} /* RT11 */
 
     return 1;                          /* Worked okay. */
 }
diff --git a/object.h b/object.h
index bc35f44..80e706d 100644
--- a/object.h
+++ b/object.h
@@ -121,6 +121,8 @@ DAMAGE.
                                           number" and two bytes offset */
 #define CPLX_CONST 020                 /* Followed by two bytes constant value */
 
+extern int rt11;                       /* Use RT11 object file format */
+
 typedef struct gsd {
     FILE           *fp;         /* The file assigned for output */
     char            buf[122];   /* space for 15 GSD entries */