diff --git a/src/runtime/baremetal.go b/src/runtime/baremetal.go
index ce69e338..5abd1371 100644
--- a/src/runtime/baremetal.go
+++ b/src/runtime/baremetal.go
@@ -52,3 +52,24 @@ func syscall_Exit(code int) {
 }
 
 const baremetal = true
+
+// timeOffset is how long the monotonic clock started after the Unix epoch. It
+// should be a positive integer under normal operation or zero when it has not
+// been set.
+var timeOffset int64
+
+//go:linkname now time.now
+func now() (sec int64, nsec int32, mono int64) {
+	mono = nanotime()
+	sec = (mono + timeOffset) / (1000 * 1000 * 1000)
+	nsec = int32((mono + timeOffset) - sec*(1000*1000*1000))
+	return
+}
+
+// AdjustTimeOffset adds the given offset to the built-in time offset. A
+// positive value adds to the time (skipping some time), a negative value moves
+// the clock into the past.
+func AdjustTimeOffset(offset int64) {
+	// TODO: do this atomically?
+	timeOffset += offset
+}
diff --git a/src/runtime/os_darwin.go b/src/runtime/os_darwin.go
index ac31b67d..be878909 100644
--- a/src/runtime/os_darwin.go
+++ b/src/runtime/os_darwin.go
@@ -11,3 +11,9 @@ const (
 	flag_MAP_PRIVATE   = 0x2
 	flag_MAP_ANONYMOUS = 0x1000 // MAP_ANON
 )
+
+// Source: https://opensource.apple.com/source/Libc/Libc-1439.100.3/include/time.h.auto.html
+const (
+	clock_REALTIME      = 0
+	clock_MONOTONIC_RAW = 4
+)
diff --git a/src/runtime/os_linux.go b/src/runtime/os_linux.go
index 7613134e..aa056173 100644
--- a/src/runtime/os_linux.go
+++ b/src/runtime/os_linux.go
@@ -11,3 +11,9 @@ const (
 	flag_MAP_PRIVATE   = 0x2
 	flag_MAP_ANONYMOUS = 0x20
 )
+
+// Source: https://github.com/torvalds/linux/blob/master/include/uapi/linux/time.h
+const (
+	clock_REALTIME      = 0
+	clock_MONOTONIC_RAW = 4
+)
diff --git a/src/runtime/runtime.go b/src/runtime/runtime.go
index 7b1b4f5a..55102411 100644
--- a/src/runtime/runtime.go
+++ b/src/runtime/runtime.go
@@ -68,27 +68,6 @@ func nanotime() int64 {
 	return ticksToNanoseconds(ticks())
 }
 
-// timeOffset is how long the monotonic clock started after the Unix epoch. It
-// should be a positive integer under normal operation or zero when it has not
-// been set.
-var timeOffset int64
-
-//go:linkname now time.now
-func now() (sec int64, nsec int32, mono int64) {
-	mono = nanotime()
-	sec = (mono + timeOffset) / (1000 * 1000 * 1000)
-	nsec = int32((mono + timeOffset) - sec*(1000*1000*1000))
-	return
-}
-
-// AdjustTimeOffset adds the given offset to the built-in time offset. A
-// positive value adds to the time (skipping some time), a negative value moves
-// the clock into the past.
-func AdjustTimeOffset(offset int64) {
-	// TODO: do this atomically?
-	timeOffset += offset
-}
-
 // Copied from the Go runtime source code.
 //go:linkname os_sigpipe os.sigpipe
 func os_sigpipe() {
diff --git a/src/runtime/runtime_tinygowasm.go b/src/runtime/runtime_tinygowasm.go
index 989fbb80..80eaa8d3 100644
--- a/src/runtime/runtime_tinygowasm.go
+++ b/src/runtime/runtime_tinygowasm.go
@@ -50,6 +50,14 @@ func putchar(c byte) {
 	}
 }
 
+//go:linkname now time.now
+func now() (sec int64, nsec int32, mono int64) {
+	mono = nanotime()
+	sec = mono / (1000 * 1000 * 1000)
+	nsec = int32(mono - sec*(1000*1000*1000))
+	return
+}
+
 // Abort executes the wasm 'unreachable' instruction.
 func abort() {
 	trap()
diff --git a/src/runtime/runtime_unix.go b/src/runtime/runtime_unix.go
index c185c4ab..464d8dfe 100644
--- a/src/runtime/runtime_unix.go
+++ b/src/runtime/runtime_unix.go
@@ -38,8 +38,6 @@ type timespec struct {
 	tv_nsec int // long: on Linux and macOS, follows the platform bitness
 }
 
-const CLOCK_MONOTONIC_RAW = 4
-
 var stackTop uintptr
 
 func postinit() {}
@@ -138,19 +136,31 @@ func sleepTicks(d timeUnit) {
 	usleep(uint(d) / 1000)
 }
 
-// Return monotonic time in nanoseconds.
-//
-// TODO: noescape
-func monotime() uint64 {
+func getTime(clock int32) uint64 {
 	ts := timespec{}
-	clock_gettime(CLOCK_MONOTONIC_RAW, &ts)
+	clock_gettime(clock, &ts)
 	return uint64(ts.tv_sec)*1000*1000*1000 + uint64(ts.tv_nsec)
 }
 
+// Return monotonic time in nanoseconds.
+func monotime() uint64 {
+	return getTime(clock_MONOTONIC_RAW)
+}
+
 func ticks() timeUnit {
 	return timeUnit(monotime())
 }
 
+//go:linkname now time.now
+func now() (sec int64, nsec int32, mono int64) {
+	ts := timespec{}
+	clock_gettime(clock_REALTIME, &ts)
+	sec = int64(ts.tv_sec)
+	nsec = int32(ts.tv_nsec)
+	mono = nanotime()
+	return
+}
+
 //go:linkname syscall_Exit syscall.Exit
 func syscall_Exit(code int) {
 	exit(code)