diff --git a/ase/lsp/error.c b/ase/lsp/error.c
index c0bb411a..791d55e6 100644
--- a/ase/lsp/error.c
+++ b/ase/lsp/error.c
@@ -1,5 +1,5 @@
 /*
- * $Id: error.c,v 1.1 2005-09-19 12:04:00 bacon Exp $
+ * $Id: error.c,v 1.2 2005-09-21 12:04:05 bacon Exp $
  */
 
 #include <xp/lsp/lsp.h>
@@ -26,7 +26,8 @@ static const xp_char_t* __errstr[] =
 	XP_TEXT("bad symbol"),
 	XP_TEXT("undefined symbol"),
 	XP_TEXT("empty body"),
-	XP_TEXT("bad value")
+	XP_TEXT("bad value"),
+	XP_TEXT("divide by zero")
 };
 
 int xp_lsp_error (xp_lsp_t* lsp, xp_char_t* buf, xp_size_t size)
diff --git a/ase/lsp/lsp.h b/ase/lsp/lsp.h
index 3d21d792..04a029e7 100644
--- a/ase/lsp/lsp.h
+++ b/ase/lsp/lsp.h
@@ -1,5 +1,5 @@
 /*
- * $Id: lsp.h,v 1.16 2005-09-20 14:38:39 bacon Exp $
+ * $Id: lsp.h,v 1.17 2005-09-21 12:04:05 bacon Exp $
  */
 
 #ifndef _XP_LSP_LSP_H_
@@ -39,7 +39,8 @@ enum
 	XP_LSP_ERR_BAD_SYMBOL,
 	XP_LSP_ERR_UNDEF_SYMBOL,
 	XP_LSP_ERR_EMPTY_BODY,
-	XP_LSP_ERR_BAD_VALUE
+	XP_LSP_ERR_BAD_VALUE,
+	XP_LSP_ERR_DIVIDE_BY_ZERO
 };
 
 /*
diff --git a/ase/lsp/prim_math.c b/ase/lsp/prim_math.c
index f9733ae6..fe4232be 100644
--- a/ase/lsp/prim_math.c
+++ b/ase/lsp/prim_math.c
@@ -1,5 +1,5 @@
 /*
- * $Id: prim_math.c,v 1.4 2005-09-20 12:06:51 bacon Exp $
+ * $Id: prim_math.c,v 1.5 2005-09-21 12:04:05 bacon Exp $
  */
 
 #include <xp/lsp/prim.h>
@@ -225,8 +225,13 @@ xp_lsp_obj_t* xp_lsp_prim_divide (xp_lsp_t* lsp, xp_lsp_obj_t* args)
 				ivalue = XP_LSP_IVALUE(tmp);
 			}
 			else {
-				if (!realnum) 
+				if (!realnum) {
+					if (XP_LSP_IVALUE(tmp) == 0) {
+						lsp->errnum = XP_LSP_ERR_DIVIDE_BY_ZERO;
+						return XP_NULL;
+					}
 					ivalue = ivalue / XP_LSP_IVALUE(tmp);
+				}
 				else
 					rvalue = rvalue / XP_LSP_IVALUE(tmp);
 			}
@@ -286,6 +291,10 @@ xp_lsp_obj_t* xp_lsp_prim_modulus (xp_lsp_t* lsp, xp_lsp_obj_t* args)
 				ivalue = XP_LSP_IVALUE(tmp);
 			}
 			else {
+				if (XP_LSP_IVALUE(tmp) == 0) {
+					lsp->errnum = XP_LSP_ERR_DIVIDE_BY_ZERO;
+					return XP_NULL;
+				}
 				ivalue = ivalue % XP_LSP_IVALUE(tmp);
 			}
 		}
@@ -294,7 +303,12 @@ xp_lsp_obj_t* xp_lsp_prim_modulus (xp_lsp_t* lsp, xp_lsp_obj_t* args)
 				ivalue = (xp_lsp_int_t)XP_LSP_RVALUE(tmp);
 			}
 			else {
-				ivalue = ivalue % (xp_lsp_int_t)XP_LSP_RVALUE(tmp);
+				xp_lsp_int_t tmpi = (xp_lsp_int_t)XP_LSP_RVALUE(tmp);
+				if (tmpi == 0) {
+					lsp->errnum = XP_LSP_ERR_DIVIDE_BY_ZERO;
+					return XP_NULL;
+				}
+				ivalue = ivalue % tmpi;
 			}
 		}
 		else {