plan9port

commit fa07e3d777fc52a7c564f71c9b7f2bba1d0e7716
parent d9ed72433f25ec45908dede1022425a3f3ed1c67
Author: rsc <devnull@localhost>
Date:   Sat, 22 Apr 2006 00:50:08 +0000

16-byte align

Diffstat:
M
src/libthread/Darwin-386.c
 | 
9
+++++++++

1 file changed, 9 insertions(+), 0 deletions(-)
diff --git a/src/libthread/Darwin-386.c b/src/libthread/Darwin-386.c
@@ -3,10 +3,19 @@
 void
 makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
 {
+	int n;
 	int *sp;
 
 	sp = (int*)ucp->uc_stack.ss_sp+ucp->uc_stack.ss_size/4;
 	sp -= argc;
+	/*
+	 * Stack pointer at call instruction (before return address
+	 * gets pushed) must be 16-byte aligned.
+	 */
+	if((uintptr)sp%4)
+		abort();
+	while((uintptr)sp%16)
+		sp--;
 	memmove(sp, &argc+1, argc*sizeof(int));
 	*--sp = 0;		/* return address */
 	ucp->uc_mcontext.mc_eip = (long)func;