diff --git a/src/gopheros/kernel/cpu/cpu_amd64.s b/src/gopheros/kernel/cpu/cpu_amd64.s
index df3bcf3..1304ca4 100644
--- a/src/gopheros/kernel/cpu/cpu_amd64.s
+++ b/src/gopheros/kernel/cpu/cpu_amd64.s
@@ -19,7 +19,8 @@ TEXT ·FlushTLBEntry(SB),NOSPLIT,$0
 
 TEXT ·SwitchPDT(SB),NOSPLIT,$0
 	// loading CR3 also triggers a TLB flush
-	MOVQ pdtPhysAddr+0(FP), CR3
+	MOVQ pdtPhysAddr+0(FP), AX
+	MOVQ AX, CR3
 	RET
 
 TEXT ·ActivePDT(SB),NOSPLIT,$0