diff --git a/libc/intrin/sched_yield.S b/libc/intrin/sched_yield.S
index c0a7d80bd..5efb639cf 100644
--- a/libc/intrin/sched_yield.S
+++ b/libc/intrin/sched_yield.S
@@ -26,6 +26,13 @@
 //	@return	0 on success, or -1 w/ errno
 sched_yield:
 
+#if SupportsXnu()
+	testb	IsXnu()
+	jz	1f
+	pause
+	ret
+#endif
+
 #if SupportsWindows()
 //	Windows Support
 //
diff --git a/libc/sysv/syscalls.sh b/libc/sysv/syscalls.sh
index 8d77dd21d..798200eca 100755
--- a/libc/sysv/syscalls.sh
+++ b/libc/sysv/syscalls.sh
@@ -60,7 +60,7 @@ scall	__sys_pipe		0x02a10721e202a016	globl hidden # NOTE: pipe2() on FreeBSD; XN
 scall	sys_select		0x1a104705d205d017	globl hidden
 scall	pselect			0x1b406e20a218afff	globl
 scall	pselect6		0xfffffffffffff10e	globl
-scall	sys_sched_yield		0x15e12a14b103c018	globl hidden # swtch() on xnu
+scall	sys_sched_yield		0x15e12a14bffff018	globl hidden # swtch on xnu? possibly removed in 12.4
 scall	__sys_mremap		0x19bffffffffff019	globl hidden
 scall	sys_mincore		0x04e04e04e204e01b	globl hidden
 scall	sys_madvise		0x04b04b04b204b01c	globl hidden