diff --git a/src/libthread/BSD.c b/src/libthread/BSD.c
new file mode 100644
index 0000000..2679cd2
--- /dev/null
+++ b/src/libthread/BSD.c
@@ -0,0 +1,384 @@
+#undef exits
+#undef _exits
+
+extern int __isthreaded;
+
+/*
+ * spin locks
+ */
+extern int _tas(int*);
+
+void
+_threadunlock(Lock *l, ulong pc)
+{
+	USED(pc);
+
+	l->held = 0;
+}
+
+int
+_threadlock(Lock *l, int block, ulong pc)
+{
+	int i;
+
+	USED(pc);
+
+	/* once fast */
+	if(!_tas(&l->held))
+		return 1;
+	if(!block)
+		return 0;
+
+	/* a thousand times pretty fast */
+	for(i=0; i<1000; i++){
+		if(!_tas(&l->held))
+			return 1;
+		sched_yield();
+	}
+	/* increasingly slow */
+	for(i=0; i<10; i++){
+		if(!_tas(&l->held))
+			return 1;
+		usleep(1);
+	}
+	for(i=0; i<10; i++){
+		if(!_tas(&l->held))
+			return 1;
+		usleep(10);
+	}
+	for(i=0; i<10; i++){
+		if(!_tas(&l->held))
+			return 1;
+		usleep(100);
+	}
+	for(i=0; i<10; i++){
+		if(!_tas(&l->held))
+			return 1;
+		usleep(1000);
+	}
+	for(i=0; i<10; i++){
+		if(!_tas(&l->held))
+			return 1;
+		usleep(10*1000);
+	}
+	/* now nice and slow */
+	for(i=0; i<1000; i++){
+		if(!_tas(&l->held))
+			return 1;
+		usleep(100*1000);
+	}
+	/* take your time */
+	while(_tas(&l->held))
+		usleep(1000*1000);
+	return 1;
+}
+
+/*
+ * For libc.
+ */
+
+typedef struct {
+	volatile long	access_lock;
+	volatile long	lock_owner;
+	volatile char	*fname;
+	volatile int	lineno;
+} spinlock_t;
+
+void
+_spinlock(spinlock_t *lk)
+{
+	lock((Lock*)&lk->access_lock);
+}
+
+/*
+ * sleep and wakeup
+ */
+static void
+ign(int x)
+{
+	USED(x);
+}
+
+static void /*__attribute__((constructor))*/
+ignusr1(int restart)
+{
+	struct sigaction sa;
+
+	memset(&sa, 0, sizeof sa);
+	sa.sa_handler = ign;
+	sigemptyset(&sa.sa_mask);
+	sigaddset(&sa.sa_mask, SIGUSR1);
+	if(restart)
+		sa.sa_flags = SA_RESTART;
+	sigaction(SIGUSR1, &sa, nil);
+}
+
+void
+_procsleep(_Procrendez *r)
+{
+	sigset_t mask;
+
+	/*
+	 * Go to sleep.
+	 *
+	 * Block USR1, set the handler to interrupt system calls,
+	 * unlock the vouslock so our waker can wake us,
+	 * and then suspend.
+	 */
+again:
+	r->asleep = 1;
+	r->pid = getpid();
+
+	sigprocmask(SIG_SETMASK, nil, &mask);
+	sigaddset(&mask, SIGUSR1);
+	sigprocmask(SIG_SETMASK, &mask, nil);
+	ignusr1(0);
+	unlock(r->l);
+	sigdelset(&mask, SIGUSR1);
+	sigsuspend(&mask);
+
+	/*
+	 * We're awake.  Make USR1 not interrupt system calls.
+	 */
+	lock(r->l);
+	ignusr1(1);
+	if(r->asleep && r->pid == getpid()){
+		/* Didn't really wake up - signal from something else */
+		goto again;
+	}
+}
+
+void
+_procwakeup(_Procrendez *r)
+{
+	if(r->asleep){
+		r->asleep = 0;
+		assert(r->pid >= 1);
+		kill(r->pid, SIGUSR1);
+	}
+}
+
+void
+_procwakeupandunlock(_Procrendez *r)
+{
+	_procwakeup(r);
+	unlock(r->l);
+}
+
+
+/*
+ * process creation and exit
+ */
+typedef struct Stackfree Stackfree;
+struct Stackfree
+{
+	Stackfree	*next;
+	int	pid;
+};
+static Lock stacklock;
+static Stackfree *stackfree;
+
+static void
+delayfreestack(uchar *stk)
+{
+	Stackfree *sf;
+
+	sf = (Stackfree*)stk;
+	sf->pid = getpid();
+	lock(&stacklock);
+	sf->next = stackfree;
+	stackfree = sf;
+	unlock(&stacklock);
+}
+
+static void
+dofreestacks(void)
+{
+	Stackfree *sf, *last, *next;
+
+	if(stackfree==nil || !canlock(&stacklock))
+		return;
+
+	for(last=nil,sf=stackfree; sf; last=sf,sf=next){
+		next = sf->next;
+		if(sf->pid >= 1 && kill(sf->pid, 0) < 0 && errno == ESRCH){
+			free(sf);
+			if(last)
+				last->next = next;
+			else
+				stackfree = next;
+			sf = last;
+		}
+	}
+	unlock(&stacklock);
+}
+
+static int
+startprocfn(void *v)
+{
+	void **a;
+	uchar *stk;
+	void (*fn)(void*);
+	Proc *p;
+
+	a = (void**)v;
+	fn = a[0];
+	p = a[1];
+	stk = a[2];
+	free(a);
+	p->osprocid = getpid();
+
+	(*fn)(p);
+
+	delayfreestack(stk);
+	_exit(0);
+	return 0;
+}
+
+void
+_procstart(Proc *p, void (*fn)(Proc*))
+{
+	void **a;
+	uchar *stk;
+	int pid;
+
+	dofreestacks();
+	a = malloc(3*sizeof a[0]);
+	if(a == nil)
+		sysfatal("_procstart malloc: %r");
+	stk = malloc(65536);
+	if(stk == nil)
+		sysfatal("_procstart malloc stack: %r");
+
+	a[0] = fn;
+	a[1] = p;
+	a[2] = stk;
+
+	pid = rfork_thread(RFPROC|RFMEM|RFNOWAIT, stk+65536-64, startprocfn, a);
+	if(pid < 0){
+		fprint(2, "_procstart rfork_thread: %r\n");
+		abort();
+	}
+}
+
+static char *threadexitsmsg;
+void
+sigusr2handler(int s)
+{
+/*	fprint(2, "%d usr2 %d\n", time(0), getpid()); */
+	if(threadexitsmsg)
+		_exits(threadexitsmsg);
+}
+
+void
+threadexitsall(char *msg)
+{
+	static int pid[1024];
+	int i, npid, mypid;
+	Proc *p;
+
+	if(msg == nil)
+		msg = "";
+	mypid = getpid();
+	lock(&_threadprocslock);
+	threadexitsmsg = msg;
+	npid = 0;
+	for(p=_threadprocs; p; p=p->next)
+		if(p->osprocid != mypid && p->osprocid >= 1)
+			pid[npid++] = p->osprocid;
+	for(i=0; i<npid; i++)
+		kill(pid[i], SIGUSR2);
+	unlock(&_threadprocslock);
+	exits(msg);
+}
+
+/*
+ * per-process data, indexed by pid
+ */
+typedef struct Perproc Perproc;
+struct Perproc
+{
+	int		pid;
+	Proc	*proc;
+};
+
+static Lock perlock;
+static Perproc perproc[1024];
+#define P ((Proc*)-1)
+
+static Perproc*
+myperproc(void)
+{
+	int i, pid, h;
+	Perproc *p;
+
+	pid = getpid();
+	h = pid%nelem(perproc);
+	for(i=0; i<nelem(perproc); i++){
+		p = &perproc[(i+h)%nelem(perproc)];
+		if(p->pid == pid)
+			return p;
+		if(p->pid == 0){
+			print("found 0 at %d (h=%d)\n", (i+h)%nelem(perproc), h);
+			break;
+		}
+	}
+	fprint(2, "myperproc %d: cannot find self\n", pid);
+	abort();
+	return nil;
+}
+
+static Perproc*
+newperproc(void)
+{
+	int i, pid, h;
+	Perproc *p;
+
+	lock(&perlock);
+	pid = getpid();
+	h = pid%nelem(perproc);
+	for(i=0; i<nelem(perproc); i++){
+		p = &perproc[(i+h)%nelem(perproc)];
+		if(p->pid == pid || p->pid == -1 || p->pid == 0){
+			p->pid = pid;
+			unlock(&perlock);
+			return p;
+		}
+	}
+	fprint(2, "newperproc %d: out of procs\n", pid);
+	abort();
+	return nil;
+}
+
+Proc*
+_threadproc(void)
+{
+	return myperproc()->proc;
+}
+
+void
+_threadsetproc(Proc *p)
+{
+	Perproc *pp;
+
+	if(p)
+		p->osprocid = getpid();
+	pp = newperproc();
+	pp->proc = p;
+	if(p == nil)
+		pp->pid = -1;
+}
+
+void
+_pthreadinit(void)
+{
+	__isthreaded = 1;
+	signal(SIGUSR2, sigusr2handler);
+}
+
+void
+_threadpexit(void)
+{
+	_exit(0);
+}
+
diff --git a/src/libthread/FreeBSD.c b/src/libthread/FreeBSD.c
index d80aaec..e6ce09b 100644
--- a/src/libthread/FreeBSD.c
+++ b/src/libthread/FreeBSD.c
@@ -1,368 +1,6 @@
 #include "threadimpl.h"
 
-#undef exits
-#undef _exits
-
-extern int __isthreaded;
-
-/*
- * spin locks
- */
-extern int _tas(int*);
-
-void
-_threadunlock(Lock *l, ulong pc)
-{
-	USED(pc);
-
-	l->held = 0;
-}
-
-int
-_threadlock(Lock *l, int block, ulong pc)
-{
-	int i;
-
-	USED(pc);
-
-	/* once fast */
-	if(!_tas(&l->held))
-		return 1;
-	if(!block)
-		return 0;
-
-	/* a thousand times pretty fast */
-	for(i=0; i<1000; i++){
-		if(!_tas(&l->held))
-			return 1;
-		sched_yield();
-	}
-	/* now nice and slow */
-	for(i=0; i<1000; i++){
-		if(!_tas(&l->held))
-			return 1;
-		usleep(100*1000);
-	}
-	/* take your time */
-	while(_tas(&l->held))
-		usleep(1000*1000);
-	return 1;
-}
-
-/*
- * For FreeBSD libc.
- */
-
-typedef struct {
-	volatile long	access_lock;
-	volatile long	lock_owner;
-	volatile char	*fname;
-	volatile int	lineno;
-} spinlock_t;
-
-void
-_spinlock(spinlock_t *lk)
-{
-	lock((Lock*)&lk->access_lock);
-}
-
-/*
- * sleep and wakeup
- */
-static void
-ign(int x)
-{
-	USED(x);
-}
-
-static void /*__attribute__((constructor))*/
-ignusr1(int restart)
-{
-	struct sigaction sa;
-
-	memset(&sa, 0, sizeof sa);
-	sa.sa_handler = ign;
-	sigemptyset(&sa.sa_mask);
-	sigaddset(&sa.sa_mask, SIGUSR1);
-	if(restart)
-		sa.sa_flags = SA_RESTART;
-	sigaction(SIGUSR1, &sa, nil);
-}
-
-void
-_procsleep(_Procrendez *r)
-{
-	sigset_t mask;
-
-	/*
-	 * Go to sleep.
-	 *
-	 * Block USR1, set the handler to interrupt system calls,
-	 * unlock the vouslock so our waker can wake us,
-	 * and then suspend.
-	 */
-again:
-	r->asleep = 1;
-	r->pid = getpid();
-
-	sigprocmask(SIG_SETMASK, nil, &mask);
-	sigaddset(&mask, SIGUSR1);
-	sigprocmask(SIG_SETMASK, &mask, nil);
-	ignusr1(0);
-	unlock(r->l);
-	sigdelset(&mask, SIGUSR1);
-	sigsuspend(&mask);
-
-	/*
-	 * We're awake.  Make USR1 not interrupt system calls.
-	 */
-	lock(r->l);
-	ignusr1(1);
-	if(r->asleep && r->pid == getpid()){
-		/* Didn't really wake up - signal from something else */
-		goto again;
-	}
-}
-
-void
-_procwakeup(_Procrendez *r)
-{
-	if(r->asleep){
-		r->asleep = 0;
-		assert(r->pid >= 1);
-		kill(r->pid, SIGUSR1);
-	}
-}
-
-void
-_procwakeupandunlock(_Procrendez *r)
-{
-	_procwakeup(r);
-	unlock(r->l);
-}
-
-
-/*
- * process creation and exit
- */
-typedef struct Stackfree Stackfree;
-struct Stackfree
-{
-	Stackfree	*next;
-	int	pid;
-};
-static Lock stacklock;
-static Stackfree *stackfree;
-
-static void
-delayfreestack(uchar *stk)
-{
-	Stackfree *sf;
-
-	sf = (Stackfree*)stk;
-	sf->pid = getpid();
-	lock(&stacklock);
-	sf->next = stackfree;
-	stackfree = sf;
-	unlock(&stacklock);
-}
-
-static void
-dofreestacks(void)
-{
-	Stackfree *sf, *last, *next;
-
-	if(stackfree==nil || !canlock(&stacklock))
-		return;
-
-	for(last=nil,sf=stackfree; sf; last=sf,sf=next){
-		next = sf->next;
-		if(sf->pid >= 1 && kill(sf->pid, 0) < 0 && errno == ESRCH){
-			free(sf);
-			if(last)
-				last->next = next;
-			else
-				stackfree = next;
-			sf = last;
-		}
-	}
-	unlock(&stacklock);
-}
-
-static int
-startprocfn(void *v)
-{
-	void **a;
-	uchar *stk;
-	void (*fn)(void*);
-	Proc *p;
-
-	a = (void**)v;
-	fn = a[0];
-	p = a[1];
-	stk = a[2];
-	free(a);
-	p->osprocid = getpid();
-
-	(*fn)(p);
-
-	delayfreestack(stk);
-	_exit(0);
-	return 0;
-}
-
-void
-_procstart(Proc *p, void (*fn)(Proc*))
-{
-	void **a;
-	uchar *stk;
-	int pid;
-
-	dofreestacks();
-	a = malloc(3*sizeof a[0]);
-	if(a == nil)
-		sysfatal("_procstart malloc: %r");
-	stk = malloc(65536);
-	if(stk == nil)
-		sysfatal("_procstart malloc stack: %r");
-
-	a[0] = fn;
-	a[1] = p;
-	a[2] = stk;
-
-	pid = rfork_thread(RFPROC|RFMEM|RFNOWAIT, stk+65536-64, startprocfn, a);
-	if(pid < 0){
-		fprint(2, "_procstart rfork_thread: %r\n");
-		abort();
-	}
-}
-
-static char *threadexitsmsg;
-void
-sigusr2handler(int s)
-{
-/*	fprint(2, "%d usr2 %d\n", time(0), getpid()); */
-	if(threadexitsmsg)
-		_exits(threadexitsmsg);
-}
-
-void
-threadexitsall(char *msg)
-{
-	static int pid[1024];
-	int i, npid, mypid;
-	Proc *p;
-
-	if(msg == nil)
-		msg = "";
-	mypid = getpid();
-	lock(&_threadprocslock);
-	threadexitsmsg = msg;
-	npid = 0;
-	for(p=_threadprocs; p; p=p->next)
-		if(p->osprocid != mypid && p->osprocid >= 1)
-			pid[npid++] = p->osprocid;
-	for(i=0; i<npid; i++)
-		kill(pid[i], SIGUSR2);
-	unlock(&_threadprocslock);
-	exits(msg);
-}
-
-/*
- * per-process data, indexed by pid
- *
- * could use modify_ldt and a segment register
- * to avoid the many calls to getpid(), but i don't
- * care -- this is compatibility code.  linux 2.6 with
- * nptl is a good enough pthreads to avoid this whole file.
- */
-typedef struct Perproc Perproc;
-struct Perproc
-{
-	int		pid;
-	Proc	*proc;
-};
-
-static Lock perlock;
-static Perproc perproc[1024];
-#define P ((Proc*)-1)
-
-static Perproc*
-myperproc(void)
-{
-	int i, pid, h;
-	Perproc *p;
-
-	pid = getpid();
-	h = pid%nelem(perproc);
-	for(i=0; i<nelem(perproc); i++){
-		p = &perproc[(i+h)%nelem(perproc)];
-		if(p->pid == pid)
-			return p;
-		if(p->pid == 0){
-			print("found 0 at %d (h=%d)\n", (i+h)%nelem(perproc), h);
-			break;
-		}
-	}
-	fprint(2, "myperproc %d: cannot find self\n", pid);
-	abort();
-	return nil;
-}
-
-static Perproc*
-newperproc(void)
-{
-	int i, pid, h;
-	Perproc *p;
-
-	lock(&perlock);
-	pid = getpid();
-	h = pid%nelem(perproc);
-	for(i=0; i<nelem(perproc); i++){
-		p = &perproc[(i+h)%nelem(perproc)];
-		if(p->pid == pid || p->pid == -1 || p->pid == 0){
-			p->pid = pid;
-			unlock(&perlock);
-			return p;
-		}
-	}
-	fprint(2, "newperproc %d: out of procs\n", pid);
-	abort();
-	return nil;
-}
-
-Proc*
-_threadproc(void)
-{
-	return myperproc()->proc;
-}
-
-void
-_threadsetproc(Proc *p)
-{
-	Perproc *pp;
-
-	if(p)
-		p->osprocid = getpid();
-	pp = newperproc();
-	pp->proc = p;
-	if(p == nil)
-		pp->pid = -1;
-}
-
-void
-_pthreadinit(void)
-{
-	__isthreaded = 1;
-	signal(SIGUSR2, sigusr2handler);
-}
-
-void
-_threadpexit(void)
-{
-	_exit(0);
-}
-
+#include "BSD.c"
 
 /*
  * FreeBSD 4 and earlier needs the context functions.
diff --git a/src/libthread/OpenBSD-power-asm.S b/src/libthread/OpenBSD-power-asm.S
new file mode 100644
index 0000000..25ceb45
--- /dev/null
+++ b/src/libthread/OpenBSD-power-asm.S
@@ -0,0 +1,125 @@
+#include <sys/syscall.h>
+#include <machine/asm.h>
+
+ENTRY(_tas)
+	li	%r0, 0
+	mr	%r4, %r3
+	lis	%r5, 0xcafe
+	ori	%r5, %r5, 0xbabe
+1:
+	lwarx	%r3, %r0, %r4
+	cmpwi	%r3, 0
+	bne	2f
+	stwcx.	%r5, %r0, %r4
+	bne-	1b
+2:
+	sync
+	blr
+
+ENTRY(_getmcontext)				/* xxx: instruction scheduling */
+	mflr	%r0
+	mfcr	%r5
+	mfctr	%r6
+	mfxer	%r7
+	stw	%r0, 0*4(%r3)
+	stw	%r5, 1*4(%r3)
+	stw	%r6, 2*4(%r3)
+	stw	%r7, 3*4(%r3)
+
+	stw	%r1, 4*4(%r3)
+	stw	%r2, 5*4(%r3)
+	li	%r5, 1			/* return value for setmcontext */
+	stw	%r5, 6*4(%r3)
+
+	stw	%r13, (0+7)*4(%r3)	/* callee-save GPRs */
+	stw	%r14, (1+7)*4(%r3)	/* xxx: block move */
+	stw	%r15, (2+7)*4(%r3)
+	stw	%r16, (3+7)*4(%r3)
+	stw	%r17, (4+7)*4(%r3)
+	stw	%r18, (5+7)*4(%r3)
+	stw	%r19, (6+7)*4(%r3)
+	stw	%r20, (7+7)*4(%r3)
+	stw	%r21, (8+7)*4(%r3)
+	stw	%r22, (9+7)*4(%r3)
+	stw	%r23, (10+7)*4(%r3)
+	stw	%r24, (11+7)*4(%r3)
+	stw	%r25, (12+7)*4(%r3)
+	stw	%r26, (13+7)*4(%r3)
+	stw	%r27, (14+7)*4(%r3)
+	stw	%r28, (15+7)*4(%r3)
+	stw	%r29, (16+7)*4(%r3)
+	stw	%r30, (17+7)*4(%r3)
+	stw	%r31, (18+7)*4(%r3)
+
+	li	%r3, 0			/* return */
+	blr
+
+ENTRY(_setmcontext)
+	lwz	%r13, (0+7)*4(%r3)	/* callee-save GPRs */
+	lwz	%r14, (1+7)*4(%r3)	/* xxx: block move */
+	lwz	%r15, (2+7)*4(%r3)
+	lwz	%r16, (3+7)*4(%r3)
+	lwz	%r17, (4+7)*4(%r3)
+	lwz	%r18, (5+7)*4(%r3)
+	lwz	%r19, (6+7)*4(%r3)
+	lwz	%r20, (7+7)*4(%r3)
+	lwz	%r21, (8+7)*4(%r3)
+	lwz	%r22, (9+7)*4(%r3)
+	lwz	%r23, (10+7)*4(%r3)
+	lwz	%r24, (11+7)*4(%r3)
+	lwz	%r25, (12+7)*4(%r3)
+	lwz	%r26, (13+7)*4(%r3)
+	lwz	%r27, (14+7)*4(%r3)
+	lwz	%r28, (15+7)*4(%r3)
+	lwz	%r29, (16+7)*4(%r3)
+	lwz	%r30, (17+7)*4(%r3)
+	lwz	%r31, (18+7)*4(%r3)
+
+	lwz	%r1, 4*4(%r3)
+	lwz	%r2, 5*4(%r3)
+
+	lwz	%r0, 0*4(%r3)
+	mtlr	%r0
+	lwz	%r0, 1*4(%r3)
+	mtcr	%r0			/* mtcrf 0xFF, %r0 */
+	lwz	%r0, 2*4(%r3)
+	mtctr	%r0
+	lwz	%r0, 3*4(%r3)
+	mtxer	%r0
+
+	lwz	%r3,	6*4(%r3)
+	blr
+
+ENTRY(rfork_thread)
+	/* sanity check */
+	cmpwi	%r4, 0
+	beq	1f
+	cmpwi	%r5, 0
+	beq	1f
+	
+	mr	%r7,%r4
+	
+	/* call rfork */
+	li	%r0, SYS_rfork
+	sc
+	cmpwi	%r0, 0
+	bne	2f
+	
+	/* check if we are parent or child */
+	cmpwi	%r3, 0
+	bnelr
+	
+	/* child */
+	mtlr	%r5	/* fp */
+	mr	%r3, %r6	/* arg */
+	mr	%r1, %r7	/* new sp */
+	blrl
+	
+	/* child returned, call _exit */
+	li	%r0, SYS_exit
+	sc
+1:
+	li	%r3, -1
+2:
+	b PIC_PLT(_C_LABEL(__cerror))
+
diff --git a/src/libthread/OpenBSD-power.c b/src/libthread/OpenBSD-power.c
new file mode 100644
index 0000000..c3c7e72
--- /dev/null
+++ b/src/libthread/OpenBSD-power.c
@@ -0,0 +1,38 @@
+#include "threadimpl.h"
+
+void
+makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
+{
+	ulong *sp, *tos;
+	va_list arg;
+
+	tos = (ulong*)ucp->uc_stack.ss_sp+ucp->uc_stack.ss_size/sizeof(ulong);
+	sp = (ulong*)((ulong)(tos-16) & ~15);
+	ucp->mc.pc = (long)func;
+	ucp->mc.sp = (long)sp;
+	va_start(arg, argc);
+	ucp->mc.r3 = va_arg(arg, long);
+	va_end(arg);
+}
+
+int
+getcontext(ucontext_t *uc)
+{
+	return _getmcontext(&uc->mc);
+}
+
+int
+setcontext(ucontext_t *uc)
+{
+	_setmcontext(&uc->mc);
+	return 0;
+}
+
+int
+swapcontext(ucontext_t *oucp, ucontext_t *ucp)
+{
+	if(getcontext(oucp) == 0)
+		setcontext(ucp);
+	return 0;
+}
+
diff --git a/src/libthread/OpenBSD.c b/src/libthread/OpenBSD.c
new file mode 100644
index 0000000..9aaa28c
--- /dev/null
+++ b/src/libthread/OpenBSD.c
@@ -0,0 +1,4 @@
+#include "threadimpl.h"
+
+#include "BSD.c"
+
diff --git a/src/libthread/mkfile b/src/libthread/mkfile
index b1bf3cc..3750c79 100644
--- a/src/libthread/mkfile
+++ b/src/libthread/mkfile
@@ -15,6 +15,8 @@
 <$PLAN9/src/mksyslib
 
 HFILES=thread.h threadimpl.h
+OpenBSD.$O FreeBSD.$O: BSD.c
+NetBSD.$O: Linux.c
 
 tprimes: tprimes.$O
 	9l -o $target $target.$O $PLAN9/lib/$LIB -l9 -lpthread
@@ -24,9 +26,8 @@
 	9l -o $target $target.$O $PLAN9/lib/$LIB -l9 -lpthread
 
 %.$O: %.c
-	$CC -I. $stem.c
+	$CC $CFLAGS -I. $stem.c
 
-NetBSD.$O: Linux.c
 
 test:V: tprimes tspawn
 	primes 1 10007 >p1.txt
@@ -40,5 +41,3 @@
 
 CLEANFILES=p1.txt p2.txt tp1.txt tp2.txt
 
-
-
diff --git a/src/libthread/Darwin-ucontext.h b/src/libthread/power-ucontext.h
similarity index 100%
rename from src/libthread/Darwin-ucontext.h
rename to src/libthread/power-ucontext.h
diff --git a/src/libthread/sysofiles.sh b/src/libthread/sysofiles.sh
index 37ab6eb..4832145 100644
--- a/src/libthread/sysofiles.sh
+++ b/src/libthread/sysofiles.sh
@@ -23,6 +23,9 @@
 *-Darwin-*)
 	echo ${SYSNAME}-${OBJTYPE}-asm.o ${SYSNAME}-${OBJTYPE}.o pthread.o
 	;;
+*-OpenBSD-*)
+	echo ${SYSNAME}-${OBJTYPE}-asm.o ${SYSNAME}-${OBJTYPE}.o $SYSNAME.o
+	;;
 *)
 	echo pthread.o
 esac
diff --git a/src/libthread/threadimpl.h b/src/libthread/threadimpl.h
index 346288d..fff874d 100644
--- a/src/libthread/threadimpl.h
+++ b/src/libthread/threadimpl.h
@@ -5,7 +5,9 @@
 #include <sys/wait.h>
 #include <sched.h>
 #include <signal.h>
-#include <ucontext.h>
+#if !defined(_OpenBSD__)
+#	include <ucontext.h>
+#endif
 #include <sys/utsname.h>
 #include "libc.h"
 #include "thread.h"
@@ -22,7 +24,12 @@
 #	define mcontext_t libthread_mcontext_t
 #	define ucontext libthread_ucontext
 #	define ucontext_t libthread_ucontext_t
-#	include "Darwin-ucontext.h"
+#	include "power-ucontext.h"
+#endif
+
+#if defined(__OpenBSD__)
+#	include "power-ucontext.h"
+extern pid_t rfork_thread(int, void*, int(*)(void*), void*);
 #endif
 
 typedef struct Context Context;