diff --git a/src/runtime/sys_windows_386.s b/src/runtime/sys_windows_386.s
index d6b521ab659..d8b14eb6442 100644
--- a/src/runtime/sys_windows_386.s
+++ b/src/runtime/sys_windows_386.s
@@ -5,6 +5,7 @@
 #include "go_asm.h"
 #include "go_tls.h"
 #include "textflag.h"
+#include "time_windows.h"
 
 // void runtime·asmstdcall(void *c);
 TEXT runtime·asmstdcall<ABIInternal>(SB),NOSPLIT,$0
@@ -331,16 +332,6 @@ TEXT runtime·switchtothread(SB),NOSPLIT,$0
 	MOVL	BP, SP
 	RET
 
-// See https://wrkhpi.wordpress.com/2007/08/09/getting-os-information-the-kuser_shared_data-structure/
-// Archived copy at:
-// http://web.archive.org/web/20210411000829/https://wrkhpi.wordpress.com/2007/08/09/getting-os-information-the-kuser_shared_data-structure/
-// Must read hi1, then lo, then hi2. The snapshot is valid if hi1 == hi2.
-#define _INTERRUPT_TIME 0x7ffe0008
-#define _SYSTEM_TIME 0x7ffe0014
-#define time_lo 0
-#define time_hi1 4
-#define time_hi2 8
-
 TEXT runtime·nanotime1(SB),NOSPLIT,$0-8
 	CMPB	runtime·useQPCTime(SB), $0
 	JNE	useQPC
diff --git a/src/runtime/sys_windows_amd64.s b/src/runtime/sys_windows_amd64.s
index ed445610840..868fd9d20f7 100644
--- a/src/runtime/sys_windows_amd64.s
+++ b/src/runtime/sys_windows_amd64.s
@@ -5,6 +5,7 @@
 #include "go_asm.h"
 #include "go_tls.h"
 #include "textflag.h"
+#include "time_windows.h"
 #include "cgo/abi_amd64.h"
 
 // maxargs should be divisible by 2, as Windows stack
@@ -341,16 +342,6 @@ TEXT runtime·switchtothread(SB),NOSPLIT|NOFRAME,$0
 	MOVQ	32(SP), SP
 	RET
 
-// See https://wrkhpi.wordpress.com/2007/08/09/getting-os-information-the-kuser_shared_data-structure/
-// Archived copy at:
-// http://web.archive.org/web/20210411000829/https://wrkhpi.wordpress.com/2007/08/09/getting-os-information-the-kuser_shared_data-structure/
-// Must read hi1, then lo, then hi2. The snapshot is valid if hi1 == hi2.
-#define _INTERRUPT_TIME 0x7ffe0008
-#define _SYSTEM_TIME 0x7ffe0014
-#define time_lo 0
-#define time_hi1 4
-#define time_hi2 8
-
 TEXT runtime·nanotime1(SB),NOSPLIT,$0-8
 	CMPB	runtime·useQPCTime(SB), $0
 	JNE	useQPC
diff --git a/src/runtime/sys_windows_arm.s b/src/runtime/sys_windows_arm.s
index 62342037980..7676bc1ff8c 100644
--- a/src/runtime/sys_windows_arm.s
+++ b/src/runtime/sys_windows_arm.s
@@ -5,6 +5,7 @@
 #include "go_asm.h"
 #include "go_tls.h"
 #include "textflag.h"
+#include "time_windows.h"
 
 // Note: For system ABI, R0-R3 are args, R4-R11 are callee-save.
 
@@ -341,16 +342,6 @@ TEXT runtime·read_tls_fallback(SB),NOSPLIT|NOFRAME,$0
 	MOVW	R0, (R0)
 	RET
 
-// See https://wrkhpi.wordpress.com/2007/08/09/getting-os-information-the-kuser_shared_data-structure/
-// Archived copy at:
-// http://web.archive.org/web/20210411000829/https://wrkhpi.wordpress.com/2007/08/09/getting-os-information-the-kuser_shared_data-structure/
-// Must read hi1, then lo, then hi2. The snapshot is valid if hi1 == hi2.
-#define _INTERRUPT_TIME 0x7ffe0008
-#define _SYSTEM_TIME 0x7ffe0014
-#define time_lo 0
-#define time_hi1 4
-#define time_hi2 8
-
 TEXT runtime·nanotime1(SB),NOSPLIT|NOFRAME,$0-8
 	MOVW	$0, R0
 	MOVB	runtime·useQPCTime(SB), R0
diff --git a/src/runtime/sys_windows_arm64.s b/src/runtime/sys_windows_arm64.s
index 9fce9a8158f..aa9ea7ed980 100644
--- a/src/runtime/sys_windows_arm64.s
+++ b/src/runtime/sys_windows_arm64.s
@@ -6,6 +6,7 @@
 #include "go_tls.h"
 #include "textflag.h"
 #include "funcdata.h"
+#include "time_windows.h"
 
 // Offsets into Thread Environment Block (pointer in R18)
 #define TEB_error 0x68
@@ -407,16 +408,6 @@ TEXT runtime·switchtothread(SB),NOSPLIT,$16-0
 	ADD	$16, RSP
 	RET
 
-// See https://wrkhpi.wordpress.com/2007/08/09/getting-os-information-the-kuser_shared_data-structure/
-// Archived copy at:
-// http://web.archive.org/web/20210411000829/https://wrkhpi.wordpress.com/2007/08/09/getting-os-information-the-kuser_shared_data-structure/
-// Must read hi1, then lo, then hi2. The snapshot is valid if hi1 == hi2.
-#define _INTERRUPT_TIME 0x7ffe0008
-#define _SYSTEM_TIME 0x7ffe0014
-#define time_lo 0
-#define time_hi1 4
-#define time_hi2 8
-
 TEXT runtime·nanotime1(SB),NOSPLIT|NOFRAME,$0-8
 	MOVB	runtime·useQPCTime(SB), R0
 	CMP	$0, R0
diff --git a/src/runtime/time_windows.h b/src/runtime/time_windows.h
new file mode 100644
index 00000000000..cd16fd163bb
--- /dev/null
+++ b/src/runtime/time_windows.h
@@ -0,0 +1,16 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Constants for fetching time values on Windows for use in asm code.
+
+// See https://wrkhpi.wordpress.com/2007/08/09/getting-os-information-the-kuser_shared_data-structure/
+// Archived copy at:
+// http://web.archive.org/web/20210411000829/https://wrkhpi.wordpress.com/2007/08/09/getting-os-information-the-kuser_shared_data-structure/
+
+// Must read hi1, then lo, then hi2. The snapshot is valid if hi1 == hi2.
+#define _INTERRUPT_TIME 0x7ffe0008
+#define _SYSTEM_TIME 0x7ffe0014
+#define time_lo 0
+#define time_hi1 4
+#define time_hi2 8