diff --git a/src/libmach/t.c b/src/libmach/t.c
new file mode 100644
index 0000000..d11cb7d
--- /dev/null
+++ b/src/libmach/t.c
@@ -0,0 +1,269 @@
+#include <u.h>
+#include <thread_db.h>
+#include <sys/ptrace.h>
+#include <errno.h>
+#include <sys/procfs.h>	/* psaddr_t */
+#include <libc.h>
+#include <mach.h>
+#include "ureg386.h"
+
+int td_get_allthreads(td_thragent_t *ta, td_thrhandle_t **pall);
+
+static char *tderrstr[] =
+{
+[TD_OK]			"no error",
+[TD_ERR]		"some error",
+[TD_NOTHR]		"no matching thread found",
+[TD_NOSV]		"no matching synchronization handle found",
+[TD_NOLWP]		"no matching light-weight process found",
+[TD_BADPH]		"invalid process handle",
+[TD_BADTH]		"invalid thread handle",
+[TD_BADSH]		"invalid synchronization handle",
+[TD_BADTA]		"invalid thread agent",
+[TD_BADKEY]		"invalid key",
+[TD_NOMSG]		"no event available",
+[TD_NOFPREGS]	"no floating-point register content available",
+[TD_NOLIBTHREAD]	"application not linked with thread library",
+[TD_NOEVENT]	"requested event is not supported",
+[TD_NOEVENT]	"requested event is not supported",
+[TD_NOCAPAB]	"capability not available",
+[TD_DBERR]		"internal debug library error",
+[TD_NOAPLIC]	"operation is not applicable",
+[TD_NOTSD]		"no thread-specific data available",
+[TD_MALLOC]		"out of memory",
+[TD_PARTIALREG]	"not entire register set was read or written",
+[TD_NOXREGS]	"X register set not available for given threads",
+[TD_TLSDEFER]	"thread has not yet allocated TLS for given module",
+[TD_VERSION]	"version mismatch twixt libpthread and libthread_db",
+[TD_NOTLS]		"there is no TLS segment in the given module",
+};
+
+static char*
+terr(int e)
+{
+	static char buf[50];
+
+	if(e < 0 || e >= nelem(tderrstr) || tderrstr[e] == nil){
+		snprint(buf, sizeof buf, "thread err %d", e);
+		return buf;
+	}
+	return tderrstr[e];
+}
+
+void
+usage(void)
+{
+	fprint(2, "usage: t pid\n");
+	exits("usage");
+}
+
+#define	STRINGSZ	128
+
+/*
+ *	print the value of dot as file:line
+ */
+void
+printsource(long dot)
+{
+	char str[STRINGSZ];
+
+	if (fileline(dot, str, STRINGSZ) >= 0)
+		print("%s", str);
+}
+
+void
+printlocals(Symbol *fn, Regs *regs)
+{
+	int i;
+	u32int v;
+	Symbol s;
+
+	for (i = 0; indexlsym(fn, i, &s)>=0; i++) {
+		if (s.class != CAUTO)
+			continue;
+		if(lget4(cormap, regs, s.loc, &v) >= 0)
+			print("\t%s.%s/\t%#lux\n", fn->name, s.name, v);
+		else
+			print("\t%s.%s/\t?\n", fn->name, s.name);
+	}
+}
+
+void
+printparams(Symbol *fn, Regs *regs)
+{
+	int i;
+	Symbol s;
+	u32int v;
+	int first = 0;
+	ulong pc, sp, bp;
+
+	if(0) print("pc=%lux sp=%lux bp=%lux ", 
+		(rget(regs, "PC", &pc), pc),
+		(rget(regs, "SP", &sp), sp),
+		(rget(regs, "BP", &bp), bp));
+	for (i = 0; indexlsym(fn, i, &s)>=0; i++) {
+		if (s.class != CPARAM)
+			continue;
+		if (first++)
+			print(", ");
+		if(0) print("(%d.%s.%ux.%x)", s.loc.type, s.loc.reg, s.loc.addr, s.loc.offset);
+		if(lget4(cormap, regs, s.loc, &v) >= 0)
+			print("%s=%#lux", s.name, v);
+		else
+			print("%s=?", s.name);
+	}
+}
+
+/*
+ *	callback on stack trace
+ */
+static int
+xtrace(Map *map, Regs *regs, ulong pc, ulong nextpc, Symbol *sym, int depth)
+{
+	char buf[512];
+
+	USED(map);
+	print("\t");
+	if(sym){
+		print("%s(", sym->name);
+		printparams(sym, regs);
+		print(")+0x%ux ", pc-sym->loc.addr);
+	}else
+		print("%#lux ", pc);
+	printsource(pc);
+
+	print(" called from ");
+	symoff(buf, 512, nextpc, CTEXT);
+	print("%s ", buf);
+/*	printsource(nextpc); */
+	print("\n");
+	if(sym)
+		printlocals(sym, regs);
+	return depth<40;
+}
+
+void
+main(int argc, char **argv)
+{
+	struct ps_prochandle p;
+	prgregset_t regs;
+	int e;
+	td_thragent_t *ta;
+	td_thrhandle_t *ts;
+	td_thrinfo_t info;
+	int i, n;
+	Ureg *u;
+	UregRegs r;
+
+	ARGBEGIN{
+	default:
+		usage();
+	}ARGEND
+
+	attachargs(argc, argv, OREAD);
+	attachdynamic();
+
+	if(!corpid && !corhdr)
+		sysfatal("could not attach to process");
+
+	p.pid = corpid;
+	if((e = td_ta_new(&p, &ta)) != TD_OK)
+		sysfatal("td_ta_new: %s", terr(e));
+	if((e = td_ta_get_nthreads(ta, &n)) != TD_OK)
+		sysfatal("td_ta_get_nthreads: %s", terr(e));
+	print("%d threads\n", n);
+
+	if((n = td_get_allthreads(ta, &ts)) < 0)
+		sysfatal("td_get_allthreads: %r");
+	print("%d threads - regs = %p\n", n, regs);
+	for(i=0; i<n; i++){
+		if((e = td_thr_get_info(&ts[i], &info)) != TD_OK)
+			sysfatal("td_thr_get_info: %s", terr(e));
+		print("%d: startfunc=%lux stkbase=%lux pc=%lux sp=%lux lid=%d\n",
+			i, info.ti_startfunc, info.ti_stkbase, info.ti_pc, info.ti_sp, info.ti_lid);	
+		if((e = td_thr_getgregs(&ts[i], regs)) != TD_OK)
+			sysfatal("td_thr_getregs: %s", terr(e));
+		print("%d: pc=%lux sp=%lux gs=%lux\n", i, regs[12], regs[15], regs[10]);
+		if((u = _linux2ureg386((UregLinux386*)regs)) == nil)
+			sysfatal("%r");
+		r.r.rw = _uregrw;
+		r.ureg = (uchar*)u;
+		stacktrace(cormap, &r.r, xtrace);
+	}
+	exits(0);
+}
+
+typedef struct AllThread AllThread;
+struct AllThread
+{
+	td_thrhandle_t *a;
+	int n;
+	int err;
+};
+
+static int
+thritercb(const td_thrhandle_t *th, void *cb)
+{
+	td_thrhandle_t **p;
+	AllThread *a;
+	int n;
+
+	a = cb;
+	if((a->n&(a->n-1)) == 0){
+		if(a->n == 0)
+			n = 1;
+		else
+			n = a->n<<1;
+		if((p = realloc(a->a, n*sizeof a->a[0])) == 0){
+			a->err = -1;
+			return -1;	/* stop iteration */
+		}
+		a->a = p;
+	}
+	a->a[a->n++] = *th;
+	return 0;
+}
+
+int
+td_get_allthreads(td_thragent_t *ta, td_thrhandle_t **pall)
+{
+	int e;
+	AllThread a;
+
+	a.a = nil;
+	a.n = 0;
+	a.err = 0;
+	if((e = td_ta_thr_iter(ta, thritercb, &a, 
+		TD_THR_ANY_STATE,
+		TD_THR_LOWEST_PRIORITY,
+		TD_SIGNO_MASK,
+		TD_THR_ANY_USER_FLAGS)) != TD_OK){
+		werrstr("%s", terr(e));
+		return -1;
+	}
+
+	if(a.err){
+		free(a.a);
+		return -1;
+	}
+
+	*pall = a.a;
+	return a.n;
+}
+
+/* 
+td_err_e td_ta_map_id2thr(const td_thragent_t *ta_p, thread_t tid,td_thrhandle_t *th_p);
+*/
+
+/*
+int
+threadregs(int tid, Regs **rp)
+{
+	check pid
+	look up tid (td_ta_map_id2thr)
+	create Regs with thr handle inside
+	rw function calls thr_getregs and then
+		pulls out the desired register
+}
+
+*/