diff --git a/sys/src/libmp/ntest.c b/sys/src/libmp/ntest.c
index 820eaa8a7..688c9df7d 100644
--- a/sys/src/libmp/ntest.c
+++ b/sys/src/libmp/ntest.c
@@ -1,3 +1,42 @@
+/*
+
+tests missing for:
+
+          mpint*  strtomp(char *buf, char **rptr, int base, mpint *b)
+          char*   mptoa(mpint *b, int base, char *buf, int blen)
+          mpint*  betomp(uchar *buf, uint blen, mpint *b)
+          int     mptobe(mpint *b, uchar *buf, uint blen, uchar **bufp)
+          void    mptober(mpint *b, uchar *buf, int blen)
+          mpint*  letomp(uchar *buf, uint blen, mpint *b)
+          int     mptole(mpint *b, uchar *buf, uint blen, uchar **bufp)
+          void    mptolel(mpint *b, uchar *buf, int blen)
+          uint    mptoui(mpint*)
+          mpint*  uitomp(uint, mpint*)
+          int     mptoi(mpint*)
+          mpint*  itomp(int, mpint*)
+          mpint*  vtomp(vlong, mpint*)
+          vlong   mptov(mpint*)
+          mpint*  uvtomp(uvlong, mpint*)
+          uvlong  mptouv(mpint*)
+          mpint*  dtomp(double, mpint*)
+          double  mptod(mpint*)
+          void    mpexp(mpint *b, mpint *e, mpint *m, mpint *res)
+          void    mpmod(mpint *b, mpint *m, mpint *remainder)
+          void    mpmodadd(mpint *b1, mpint *b2, mpint *m, mpint *sum)
+          void    mpmodsub(mpint *b1, mpint *b2, mpint *m, mpint *diff)
+          void    mpmodmul(mpint *b1, mpint *b2, mpint *m, mpint *prod)
+          void    mpsel(int s, mpint *b1, mpint *b2, mpint *res)
+          void    mpextendedgcd(mpint *a, mpint *b, mpint *d, mpint *x, mpint *y)
+          void    mpinvert(mpint *b, mpint *m, mpint *res)
+          void    mpdigdiv(mpdigit *dividend, mpdigit divisor, mpdigit *quotient)
+          void    mpvecadd(mpdigit *a, int alen, mpdigit *b, int blen, mpdigit *sum)
+          void    mpvecsub(mpdigit *a, int alen, mpdigit *b, int blen, mpdigit *diff)
+          void    mpvecdigmuladd(mpdigit *b, int n, mpdigit m, mpdigit *p)
+          int     mpvecdigmulsub(mpdigit *b, int n, mpdigit m, mpdigit *p)
+          void    mpvecmul(mpdigit *a, int alen, mpdigit *b, int blen,mpdigit *p)
+          int     mpveccmp(mpdigit *a, int alen, mpdigit *b, int blen)
+*/
+
 #include <u.h>
 #include <libc.h>
 #include <mp.h>
@@ -40,6 +79,9 @@ ldnorm(ldint *a)
 			if(a->b[i] != a->b[a->n-1])
 				break;
 		ldbits(a, i + 2);
+	}else{
+		ldbits(a, 1);
+		a->b[0] = 0;
 	}
 	return a;
 }
@@ -55,6 +97,10 @@ ldneg(ldint *a)
 		a->b[i] = c & 1;
 		c >>= 1;
 	}
+	if(c != a->b[a->n - 1]){
+		ldbits(a, a->n + 1);
+		a->b[a->n - 1] = c;
+	}
 }
 
 static int
@@ -69,6 +115,7 @@ ldnew(int n)
 	ldint *a;
 	
 	a = malloc(sizeof(ldint));
+	if(n <= 0) n = 1;
 	a->b = malloc(n);
 	a->n = n;
 	return a;
@@ -87,6 +134,7 @@ ldsanity(ldint *a)
 {
 	int i;
 	
+	assert(a->n > 0);
 	for(i = 0; i < a->n; i++)
 		assert(a->b[i] < 2);
 }
@@ -177,6 +225,7 @@ pow2told(int n, ldint *a)
 	memset(a->b, 0, k+2);
 	a->b[k] = 1;
 	if(n < 0) ldneg(a);
+	ldnorm(a);
 	return a;
 }
 
@@ -206,6 +255,74 @@ ldfmt(Fmt *f)
 	return 0;
 }
 
+static int
+mpdetfmt(Fmt *f)
+{
+	mpint *a;
+	int i, j;
+	
+	a = va_arg(f->args, mpint *);
+	fmtprint(f, "(sign=%d,top=%d,size=%d,", a->sign, a->top, a->size);
+	for(i=0;i<a->top;){
+		fmtprint(f, "%ullx", (uvlong)a->p[i]);
+		if(++i == a->top) break;
+		fmtrune(f, ',');
+		for(j = i+1; j < a->top;  j++)
+			if(a->p[i] != a->p[j])
+				goto next;
+		fmtprint(f, "...");
+		break;
+	next:;
+	}
+	fmtrune(f, '|');
+	for(i=a->top;i<a->size;){
+		fmtprint(f, "%ullx", (uvlong)a->p[i]);
+		if(++i == a->size) break;
+		fmtrune(f, ',');
+		for(j = i+1; j < a->top;  j++)
+			if(a->p[i] != a->p[j])
+				goto next2;
+		fmtprint(f, "...");
+		break;
+	next2:;
+	}
+	fmtrune(f, ')');
+	return 0;
+}
+
+static int
+ldcmp(ldint *a, ldint *b)
+{
+	int x, y;
+	int i, r;
+	
+	r = max(a->n, b->n);
+	if(a->b[a->n-1] != b->b[b->n-1])
+		return b->b[b->n - 1] - a->b[a->n - 1];
+	for(i = r - 1; --i >= 0; ){
+		x = ldget(a, i);
+		y = ldget(b, i);
+		if(x != y)
+			return x - y;
+	}
+	return 0;
+}
+
+static int
+ldmagcmp(ldint *a, ldint *b)
+{
+	int s1, s2, r;
+	
+	s1 = a->b[a->n - 1];
+	s2 = b->b[b->n - 1];
+	if(s1) ldneg(a);
+	if(s2) ldneg(b);
+	r = ldcmp(a, b);
+	if(s1) ldneg(a);
+	if(s2) ldneg(b);
+	return r;
+}
+
 static int
 ldmpeq(ldint *a, mpint *b)
 {
@@ -265,6 +382,50 @@ ldadd(ldint *a, ldint *b, ldint *q)
 	ldnorm(q);
 }
 
+static void
+ldmagadd(ldint *a, ldint *b, ldint *q)
+{
+	int i, r, s1, s2, c1, c2, co;
+	
+	r = max(a->n, b->n) + 2;
+	ldbits(q, r);
+	co = 0;
+	s1 = c1 = a->b[a->n - 1] & 1;
+	s2 = c2 = b->b[b->n - 1] & 1;
+	for(i = 0; i < r; i++){
+		c1 += s1 ^ ldget(a, i) & 1;
+		c2 += s2 ^ ldget(b, i) & 1;
+		co += (c1 & 1) + (c2 & 1);
+		q->b[i] = co & 1;
+		co >>= 1;
+		c1 >>= 1;
+		c2 >>= 1;
+	}
+	ldnorm(q);
+}
+
+static void
+ldmagsub(ldint *a, ldint *b, ldint *q)
+{
+	int i, r, s1, s2, c1, c2, co;
+	
+	r = max(a->n, b->n) + 2;
+	ldbits(q, r);
+	co = 0;
+	s1 = c1 = a->b[a->n - 1] & 1;
+	s2 = c2 = 1 ^ b->b[b->n - 1] & 1;
+	for(i = 0; i < r; i++){
+		c1 += s1 ^ ldget(a, i) & 1;
+		c2 += s2 ^ ldget(b, i) & 1;
+		co += (c1 & 1) + (c2 & 1);
+		q->b[i] = co & 1;
+		co >>= 1;
+		c1 >>= 1;
+		c2 >>= 1;
+	}
+	ldnorm(q);
+}
+
 static void
 ldsub(ldint *a, ldint *b, ldint *q)
 {
@@ -474,6 +635,108 @@ ldxor(ldint *a, ldint *b, ldint *q)
 	ldnorm(q);
 }
 
+static void
+ldleft(ldint *a, int n, ldint *b)
+{
+	int i, c;
+
+	if(n < 0){
+		if(a->n <= -n){
+			b->n = 0;
+			ldnorm(b);
+			return;
+		}
+		c = 0;
+		if(a->b[a->n - 1])
+			for(i = 0; i < -n; i++)
+				if(a->b[i]){
+					c = 1;
+					break;
+				}
+		ldbits(b, a->n + n);
+		for(i = 0; i < a->n + n; i++){
+			c += a->b[i - n] & 1;
+			b->b[i] = c & 1;
+			c >>= 1;
+		}
+	}else{
+		ldbits(b, a->n + n);
+		memmove(b->b + n, a->b, a->n);
+		memset(b->b, 0, n);
+	}
+	ldnorm(b);
+}
+
+static void
+ldasr(ldint *a, int n, ldint *b)
+{
+	if(n < 0){
+		ldleft(a, -n, b);
+		return;
+	}
+	if(a->n <= n){
+		ldbits(b, 1);
+		b->b[0] = a->b[a->n - 1];
+		return;
+	}
+	ldbits(b, a->n - n);
+	memmove(b->b, a->b + n, a->n - n);
+	ldnorm(b);
+}
+
+static void
+ldtrunc(ldint *a, int n, ldint *b)
+{
+	ldbits(b, n+1);
+	b->b[n] = 0;
+	if(a->n >= n)
+		memmove(b->b, a->b, n);
+	else{
+		memmove(b->b, a->b, a->n);
+		memset(b->b + a->n, a->b[a->n - 1], n - a->n);
+	}
+	ldnorm(b);
+}
+
+static void
+ldxtend(ldint *a, int n, ldint *b)
+{
+	ldbits(b, n);
+	if(a->n >= n)
+		memmove(b->b, a->b, n);
+	else{
+		memmove(b->b, a->b, a->n);
+		memset(b->b + a->n, a->b[a->n - 1], n - a->n);
+	}
+	ldnorm(b);
+}
+
+static void
+mpnot_(mpint *a, int, mpint *b)
+{
+	mpnot(a, b);
+}
+
+static void
+ldnot(ldint *a, int, ldint *b)
+{
+	int i;
+	
+	ldbits(b, a->n);
+	for(i = 0; i < a->n; i++)
+		b->b[i] = a->b[i] ^ 1;
+}
+
+enum { NTEST = 2*257 };
+static void
+testgen(int i, ldint *a)
+{
+	if(i < 257)
+		itold(i-128, a);
+	else
+		pow2told(i-385, a);
+}
+
 typedef struct Test2 Test2;
 struct Test2 {
 	char *name;
@@ -481,6 +744,14 @@ struct Test2 {
 	void (*ref)(ldint *, ldint *, ldint *);
 };
 
+typedef struct Test1i Test1i;
+struct Test1i {
+	char *name;
+	enum { NONEG = 1 } flags;
+	void (*dut)(mpint *, int, mpint *);
+	void (*ref)(ldint *, int, ldint *);
+};
+
 int
 validate(char *name, ldint *ex, mpint *res, char *str)
 {
@@ -564,31 +835,21 @@ run2(Test2 *t)
 	b = ldnew(32);
 	c = ldnew(32);
 	ok = 1;
-	for(i = -128; i <= 128; i++)
-		for(j = -128; j <= 128; j++){
-			itold(i, a);
-			itold(j, b);
+	for(i = 0; i < NTEST; i++){
+		for(j = 0; j < NTEST; j++){
+			testgen(i, a);
+			testgen(j, b);
 			ok &= test2(t, a, b);
-			pow2told(i, a);
-			itold(j, b);
-			ok &= test2(t, a, b);
-			ok &= test2(t, b, a);
-			pow2told(i, a);
-			pow2told(j, b);
-			ok &= test2(t, a, b);			
 		}
+		itold(i, a);
+		ok &= test2x(t, a);
+	}
 	for(i = 1; i <= 4; i++)
 		for(j = 1; j <= 4; j++){
 			ldrand(i * Dbits, a);
 			ldrand(j * Dbits, b);
 			ok &= test2(t, a, b);
 		}
-	for(i = -128; i <= 128; i++){
-		itold(i, a);
-		ok &= test2x(t, a);
-		pow2told(i, a);
-		ok &= test2x(t, a);
-	}
 	ldfree(a);
 	ldfree(b);
 	if(ok)
@@ -596,15 +857,17 @@ run2(Test2 *t)
 }
 
 Test2 tests2[] = {
-	"mpdiv(q)", mpdivq, lddivq,
-	"mpdiv(r)", mpdivr, lddivr,
-	"mpmul", mpmul, ldmul,
 	"mpadd", mpadd, ldadd,
+	"mpmagadd", mpmagadd, ldmagadd,
 	"mpsub", mpsub, ldsub,
+	"mpmagsub", mpmagsub, ldmagsub,
 	"mpand", mpand, ldand,
 	"mpor", mpor, ldor,
 	"mpbic", mpbic, ldbic,
 	"mpxor", mpxor, ldxor,
+	"mpmul", mpmul, ldmul,
+	"mpdiv(q)", mpdivq, lddivq,
+	"mpdiv(r)", mpdivr, lddivr,
 };
 
 void
@@ -616,10 +879,168 @@ all2(void)
 		run2(t);
 }
 
+int
+test1i(Test1i *t, ldint *a, int b)
+{
+	ldint *c;
+	mpint *ma, *rc;
+	int rv;
+	
+	c = ldnew(0);
+	t->ref(a, b, c);
+	ldsanity(a);
+	ldsanity(c);
+	ma = ldtomp(a, nil);
+	rc = mptarget();
+	t->dut(ma, b, rc);
+	rv = validate(t->name, c, rc, smprint("%L and %d", a, b));
+	ldtomp(a, ma);
+	t->dut(ma, b, ma);
+	rv = validate(t->name, c, ma, smprint("%L (aliased to result) and %d", a, b));
+	ldfree(c);
+	mpfree(rc);
+	mpfree(ma);
+	return rv;
+}
+
+void
+run1i(Test1i *t)
+{
+	int i, j, ok;
+	ldint *a, *c;
+	
+	a = ldnew(32);
+	c = ldnew(32);
+	ok = 1;
+	for(i = 0; i < NTEST; i++)
+		for(j = (t->flags & NONEG) != 0 ? 0 : -128; j <= 128; j++){
+			testgen(i, a);
+			ok &= test1i(t, a, j);		
+		}
+	ldfree(a);
+	ldfree(c);
+	if(ok)
+		fprint(2, "%s: passed\n", t->name);
+}
+
+
+Test1i tests1i[] = {
+	"mpleft", 0, mpleft, ldleft,
+	"mpasr", 0, mpasr, ldasr,
+	"mptrunc", NONEG, mptrunc, ldtrunc,
+	"mpxtend", NONEG, mpxtend, ldxtend,
+	"mpnot", NONEG, mpnot_, ldnot, /* hack */
+};
+
+void
+all1i(void)
+{
+	Test1i *t;
+	
+	for(t = tests1i; t < tests1i + nelem(tests1i); t++)
+		run1i(t);
+}
+
+void
+siglo(void)
+{
+	int i, j, k;
+	ldint *a;
+	mpint *ma;
+	int sigok, lowok0;
+	
+	a = ldnew(32);
+	ma = mpnew(0);
+	sigok = 1;
+	lowok0 = 1;
+	for(i = 0; i < NTEST; i++){
+		testgen(i, a);
+		for(j = 0; j < a->n; j++)
+			if(a->b[j] != 0)
+				break;
+		if(j == a->n) j = 0;
+		ldtomp(a, ma);
+		k = mplowbits0(ma);
+		if(k != j){
+			fprint(2, "FAIL: mplowbits0: %#B: got %d, expected %d\n", ma, k, j);
+			lowok0 = 0;
+		}
+		for(j = a->n - 2; j >= 0; j--)
+			if(a->b[j] != a->b[a->n-1])
+				break;
+		for(k = j-1; k >= 0; k--)
+			if(a->b[k] != 0)
+				break;
+		if(a->b[a->n - 1] && k < 0) j++;
+		j++;
+		ldtomp(a, ma);
+		k = mpsignif(ma);
+		if(k != j){
+			fprint(2, "FAIL: mpsignif: %#B: got %d, expected %d\n", ma, k, j);
+			sigok = 0;
+		}
+	}
+	if(sigok) fprint(2, "mpsignif: passed\n");
+	if(lowok0) fprint(2, "mplowbits0: passed\n");
+	ldfree(a);
+	mpfree(ma);
+}
+
+void
+cmptest(void)
+{
+	int i, j, k, l;
+	ldint *a, *b;
+	mpint *ma, *mb;
+	int cmpok, magcmpok;
+	
+	a = ldnew(32);
+	b = ldnew(32);
+	ma = mpnew(0);
+	mb = mpnew(0);
+	cmpok = 1;
+	magcmpok = 1;
+	for(i = 0; i < NTEST; i++)
+		for(j = 0; j < NTEST; j++){
+			testgen(i, a);
+			testgen(j, b);
+			ldtomp(a, ma);
+			ldtomp(b, mb);
+			l = ldcmp(a, b);
+			k = mpcmp(ma, mb);
+			if(k < 0) k = -1;
+			if(k > 0) k = 1;
+			if(k != l){
+				fprint(2, "FAIL: mpcmp: %L and %L: got %d, expected %d\n", a, b, k, l);
+				cmpok = 1;
+			}
+			ldtomp(a, ma);
+			ldtomp(b, mb);
+			l = ldmagcmp(a, b);
+			k = mpmagcmp(ma, mb);
+			if(k < 0) k = -1;
+			if(k > 0) k = 1;
+			if(k != l){
+				fprint(2, "FAIL: mpmagcmp: %L and %L: got %d, expected %d\n", a, b, k, l);
+				magcmpok = 1;
+			}
+		}
+	ldfree(a);
+	ldfree(b);
+	mpfree(ma);
+	mpfree(mb);
+	if(cmpok) fprint(2, "mpcmp: passed\n");
+	if(magcmpok) fprint(2, "mpmagcmp: passed\n");
+}
+
 void
 main()
 {
 	fmtinstall('B', mpfmt);
+	fmtinstall(L'β', mpdetfmt);
 	fmtinstall('L', ldfmt);
+	siglo();
+	cmptest();
+	all1i();
 	all2();
 }