diff --git a/assert.asm b/assert.asm
index 4bb73f4..5264423 100644
--- a/assert.asm
+++ b/assert.asm
@@ -22,11 +22,12 @@ Assert   start                          dummy routine
 
 ****************************************************************
 *
-*  void __assert (char *f, int l)
+*  void __assert (char *f, unsigned l, char *s)
 *
 *  Inputs:
 *        f - pointer to the file name
 *        l - line number
+*        s - assertion string
 *
 ****************************************************************
 *
@@ -44,5 +45,35 @@ __assert start
 
          creturn
 
-msg      dc    c'Assertion failed: file %s, line %d; assertion: %s',i1'10,0'
+msg      dc    c'Assertion failed: file %s, line %u; assertion: %s',i1'10,0'
+         end
+
+****************************************************************
+*
+*  void __assert2 (char *f, unsigned l, char *fn, char *s)
+*
+*  Inputs:
+*        f - pointer to the file name
+*        l - line number
+*        fn - function name
+*        s - assertion string
+*
+****************************************************************
+*
+__assert2 start
+
+         csubroutine (4:f,2:l,4:fn,4:s),0
+
+         ph4   <s
+         ph4   <fn
+         ph2   <l
+         ph4   <f
+         ph4   #msg
+         ph4   >stderr
+         jsl   fprintf
+         jsl   abort
+
+         creturn
+
+msg      dc    c'Assertion failed: file %s, line %u, function %s; assertion: %s',i1'10,0'
          end