diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index c0ffc1fd46b..b8d29285d52 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,10 @@
+Fri Jul  2 13:51:04 1993  Ian Lance Taylor  (ian@cygnus.com)
+
+	* configure.in (mipos-*-riscos*): New host and target; use riscos.
+	* config/mips/nm-riscos.h: If BSD43_NBPG is not defined by
+	vmparam.h, include machparam.h.
+	(KERNEL_U_ADDR): Define to be BSD43_UADDR.
+
 Fri Jul  2 13:39:48 1993  Jim Kingdon  (kingdon@lioth.cygnus.com)
 
 	* c-exp.y (yylex): Give error if unmatched single quote.
diff --git a/gdb/config/mips/nm-riscos.h b/gdb/config/mips/nm-riscos.h
index 991c88b9a7d..34ee24b2799 100644
--- a/gdb/config/mips/nm-riscos.h
+++ b/gdb/config/mips/nm-riscos.h
@@ -17,8 +17,13 @@ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
 #define PCB_OFFSET(FIELD) ((int)&((struct user*)0)->u_pcb.FIELD)
 
 #include <bsd43/machine/vmparam.h>
+#ifndef BSD43_NBPG
+/* RISC/os 5.0 defines this in machparam.h.  */
+#include <bsd43/machine/machparam.h>
+#endif
 #define NBPG BSD43_NBPG
 #define UPAGES BSD43_UPAGES
+#define KERNEL_U_ADDR BSD43_UADDR
 
 #define REGISTER_U_ADDR(addr, blockend, regno) 		\
 	      if (regno < FP0_REGNUM) \