diff --git a/src/runtime/sys_darwin_386.s b/src/runtime/sys_darwin_386.s
index 83f4709f385fb..b5e65e686964b 100644
--- a/src/runtime/sys_darwin_386.s
+++ b/src/runtime/sys_darwin_386.s
@@ -196,15 +196,16 @@ timeloop:
 
 systime:
 	// Fall back to system call (usually first call in this thread)
-	LEAL	12(SP), AX	// must be non-nil, unused
+	LEAL	16(SP), AX	// must be non-nil, unused
 	MOVL	AX, 4(SP)
 	MOVL	$0, 8(SP)	// time zone pointer
+	MOVL	$0, 12(SP)	// required as of Sierra; Issue 16570
 	MOVL	$116, AX
 	INT	$0x80
 	CMPL	AX, $0
 	JNE	inreg
-	MOVL	12(SP), AX
-	MOVL	16(SP), DX
+	MOVL	16(SP), AX
+	MOVL	20(SP), DX
 inreg:
 	// sec is in AX, usec in DX
 	// convert to DX:AX nsec
diff --git a/src/runtime/sys_darwin_amd64.s b/src/runtime/sys_darwin_amd64.s
index e4837ce2915ba..ea2cc068f6913 100644
--- a/src/runtime/sys_darwin_amd64.s
+++ b/src/runtime/sys_darwin_amd64.s
@@ -157,6 +157,7 @@ systime:
 	// Fall back to system call (usually first call in this thread).
 	MOVQ	SP, DI
 	MOVQ	$0, SI
+	MOVQ	$0, DX  // required as of Sierra; Issue 16570
 	MOVL	$(0x2000000+116), AX
 	SYSCALL
 	CMPQ	AX, $0