diff --git a/sys/src/9/pc/fns.h b/sys/src/9/pc/fns.h
index 7bbaeb551..b107707ae 100644
--- a/sys/src/9/pc/fns.h
+++ b/sys/src/9/pc/fns.h
@@ -78,7 +78,6 @@ int	iprint(char*, ...);
 int	isaconfig(char*, int, ISAConf*);
 void*	kaddr(ulong);
 #define	kmapinval()
-void	ldmxcsr(ulong);
 void	lgdt(ushort[3]);
 void	lldt(ulong);
 void	lidt(ushort[3]);
diff --git a/sys/src/9/pc/fpu.c b/sys/src/9/pc/fpu.c
index c7aa47bb7..e9467fc52 100644
--- a/sys/src/9/pc/fpu.c
+++ b/sys/src/9/pc/fpu.c
@@ -16,6 +16,7 @@ extern void fpsserestore(FPsave*);
 extern void fpssesave(FPsave*);
 extern void fpx87restore0(FPsave*);
 extern void fpx87save0(FPsave*);
+extern void ldmxcsr(ulong);
 
 void
 putxcr0(ulong)