diff --git a/ports/ChangeLog.arm b/ports/ChangeLog.arm
index 73f32135c0..1e7a35c6a9 100644
--- a/ports/ChangeLog.arm
+++ b/ports/ChangeLog.arm
@@ -1,3 +1,9 @@
+2013-07-03  Joseph Myers  <joseph@codesourcery.com>
+
+	* sysdeps/arm/include/bits/setjmp.h [_ISOMAC] (JMP_BUF_REGLIST):
+	Do not define.
+	[_ISOMAC] (__JMP_BUF_SP): Likewise.
+
 2013-07-02  Joseph Myers  <joseph@codesourcery.com>
 
 	* sysdeps/arm/libm-test-ulps: Regenerated.
diff --git a/ports/sysdeps/arm/include/bits/setjmp.h b/ports/sysdeps/arm/include/bits/setjmp.h
index 23d8f75cf2..1559d7b8e6 100644
--- a/ports/sysdeps/arm/include/bits/setjmp.h
+++ b/ports/sysdeps/arm/include/bits/setjmp.h
@@ -24,11 +24,13 @@
 # include <sysdeps/arm/bits/setjmp.h>
 #endif
 
+#ifndef _ISOMAC
 /* Register list for a ldm/stm instruction to load/store
    the general registers from a __jmp_buf.  */
-#define JMP_BUF_REGLIST		{v1-v6, sl, fp, sp, lr}
+# define JMP_BUF_REGLIST	{v1-v6, sl, fp, sp, lr}
 
 /* Index of __jmp_buf where the sp register resides.  */
-#define __JMP_BUF_SP		8
+# define __JMP_BUF_SP		8
+#endif
 
 #endif  /* include/bits/setjmp.h */