diff --git a/src/syscall/syscall_windows.go b/src/syscall/syscall_windows.go
index ba69133d819..4a576486d11 100644
--- a/src/syscall/syscall_windows.go
+++ b/src/syscall/syscall_windows.go
@@ -414,19 +414,22 @@ const ptrSize = unsafe.Sizeof(uintptr(0))
 // See https://msdn.microsoft.com/en-us/library/windows/desktop/aa365542(v=vs.85).aspx
 func setFilePointerEx(handle Handle, distToMove int64, newFilePointer *int64, whence uint32) error {
 	var e1 Errno
-	switch runtime.GOARCH {
-	default:
-		panic("unsupported architecture")
-	case "amd64":
+	if unsafe.Sizeof(uintptr(0)) == 8 {
 		_, _, e1 = Syscall6(procSetFilePointerEx.Addr(), 4, uintptr(handle), uintptr(distToMove), uintptr(unsafe.Pointer(newFilePointer)), uintptr(whence), 0, 0)
-	case "386":
-		// distToMove is a LARGE_INTEGER:
-		// https://msdn.microsoft.com/en-us/library/windows/desktop/aa383713(v=vs.85).aspx
-		_, _, e1 = Syscall6(procSetFilePointerEx.Addr(), 5, uintptr(handle), uintptr(distToMove), uintptr(distToMove>>32), uintptr(unsafe.Pointer(newFilePointer)), uintptr(whence), 0)
-	case "arm":
-		// distToMove must be 8-byte aligned per ARM calling convention
-		// https://msdn.microsoft.com/en-us/library/dn736986.aspx#Anchor_7
-		_, _, e1 = Syscall6(procSetFilePointerEx.Addr(), 6, uintptr(handle), 0, uintptr(distToMove), uintptr(distToMove>>32), uintptr(unsafe.Pointer(newFilePointer)), uintptr(whence))
+	} else {
+		// Different 32-bit systems disgaree about whether distToMove starts 8-byte aligned.
+		switch runtime.GOARCH {
+		default:
+			panic("unsupported 32-bit architecture")
+		case "386":
+			// distToMove is a LARGE_INTEGER:
+			// https://msdn.microsoft.com/en-us/library/windows/desktop/aa383713(v=vs.85).aspx
+			_, _, e1 = Syscall6(procSetFilePointerEx.Addr(), 5, uintptr(handle), uintptr(distToMove), uintptr(distToMove>>32), uintptr(unsafe.Pointer(newFilePointer)), uintptr(whence), 0)
+		case "arm":
+			// distToMove must be 8-byte aligned per ARM calling convention
+			// https://msdn.microsoft.com/en-us/library/dn736986.aspx#Anchor_7
+			_, _, e1 = Syscall6(procSetFilePointerEx.Addr(), 6, uintptr(handle), 0, uintptr(distToMove), uintptr(distToMove>>32), uintptr(unsafe.Pointer(newFilePointer)), uintptr(whence))
+		}
 	}
 	if e1 != 0 {
 		return errnoErr(e1)
diff --git a/src/syscall/syscall_windows_386.go b/src/syscall/syscall_windows_386.go
deleted file mode 100644
index e82b540b4b6..00000000000
--- a/src/syscall/syscall_windows_386.go
+++ /dev/null
@@ -1,5 +0,0 @@
-// Copyright 2009 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.
-
-package syscall
diff --git a/src/syscall/syscall_windows_amd64.go b/src/syscall/syscall_windows_amd64.go
deleted file mode 100644
index e82b540b4b6..00000000000
--- a/src/syscall/syscall_windows_amd64.go
+++ /dev/null
@@ -1,5 +0,0 @@
-// Copyright 2009 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.
-
-package syscall
diff --git a/src/syscall/zerrors_windows_386.go b/src/syscall/zerrors_windows_386.go
deleted file mode 100644
index 8bc5b6b1943..00000000000
--- a/src/syscall/zerrors_windows_386.go
+++ /dev/null
@@ -1,5 +0,0 @@
-// Copyright 2011 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.
-
-package syscall
diff --git a/src/syscall/zerrors_windows_amd64.go b/src/syscall/zerrors_windows_amd64.go
deleted file mode 100644
index 8bc5b6b1943..00000000000
--- a/src/syscall/zerrors_windows_amd64.go
+++ /dev/null
@@ -1,5 +0,0 @@
-// Copyright 2011 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.
-
-package syscall
diff --git a/src/syscall/zsysnum_windows_386.go b/src/syscall/zsysnum_windows_386.go
deleted file mode 100644
index 36bf065d1fd..00000000000
--- a/src/syscall/zsysnum_windows_386.go
+++ /dev/null
@@ -1,3 +0,0 @@
-// nothing to see here
-
-package syscall
diff --git a/src/syscall/zsysnum_windows_amd64.go b/src/syscall/zsysnum_windows_amd64.go
deleted file mode 100644
index 36bf065d1fd..00000000000
--- a/src/syscall/zsysnum_windows_amd64.go
+++ /dev/null
@@ -1,3 +0,0 @@
-// nothing to see here
-
-package syscall