diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index c1a26f158b..fb343d55f0 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,7 @@
+Wed Jun 23 11:34:21 1993  Jim Kingdon  (kingdon@cygnus.com)
+
+	* hosts/riscos.h: New file.
+
 Tue Jun 22 14:35:20 1993  Ken Raeburn  (raeburn@poseidon.cygnus.com)
 
 	* elfcode.h (bfd_section_from_shdr, case SHT_PROGBITS): Even if
diff --git a/bfd/hosts/.Sanitize b/bfd/hosts/.Sanitize
index fcd7cd4422..45a4f452a8 100644
--- a/bfd/hosts/.Sanitize
+++ b/bfd/hosts/.Sanitize
@@ -52,6 +52,7 @@ miniframe.h
 mipsbsd.h
 news.h
 ncr3000.h
+riscos.h
 rs6000.h
 rtbsd.h
 solaris2.h
diff --git a/bfd/hosts/riscos.h b/bfd/hosts/riscos.h
new file mode 100644
index 0000000000..f894edb361
--- /dev/null
+++ b/bfd/hosts/riscos.h
@@ -0,0 +1,15 @@
+/* RISC/os 4.52C, and presumably other versions.  */
+
+#include "hosts/std-host.h"
+
+#include <bsd43/machine/machparam.h>
+#include <bsd43/machine/vmparam.h>
+
+#define HOST_TEXT_START_ADDR BSD43_USRTEXT
+#define HOST_DATA_START_ADDR BSD43_USRDATA
+#define HOST_STACK_END_ADDR BSD43_USRSTACK
+
+/* This is just needed for a.out formats where the executable does not
+   identify the architecture.  I'm not sure whether RISC/os is such a case
+   or not.  */
+#define HOST_MACHINE_ARCH bfd_arch_mips