--- /n/sources/plan9/sys/include/mp.h	Mon Sep  7 20:29:15 2009
+++ /sys/include/mp.h	Wed Jun 26 23:40:07 2024
@@ -45,8 +45,10 @@
 char*	mptoa(mpint*, int, char*, int);
 mpint*	letomp(uchar*, uint, mpint*);	/* byte array, little-endian */
 int	mptole(mpint*, uchar*, uint, uchar**);
+void	mptolel(mpint *b, uchar *p, int n);
 mpint*	betomp(uchar*, uint, mpint*);	/* byte array, big-endian */
 int	mptobe(mpint*, uchar*, uint, uchar**);
+void	mptober(mpint *b, uchar *p, int n);
 uint	mptoui(mpint*);			/* unsigned int */
 mpint*	uitomp(uint, mpint*);
 int	mptoi(mpint*);			/* int */
--- /n/sources/plan9/sys/include/ape/mp.h	Mon Feb  4 14:12:44 2013
+++ /sys/include/ape/mp.h	Wed Jun 26 23:40:09 2024
@@ -54,8 +54,10 @@
 char*	mptoa(mpint*, int, char*, int);
 mpint*	letomp(uchar*, uint, mpint*);	/* byte array, little-endian */
 int	mptole(mpint*, uchar*, uint, uchar**);
+void	mptolel(mpint *b, uchar *p, int n);
 mpint*	betomp(uchar*, uint, mpint*);	/* byte array, big-endian */
 int	mptobe(mpint*, uchar*, uint, uchar**);
+void	mptober(mpint *b, uchar *p, int n);
 uint	mptoui(mpint*);			/* unsigned int */
 mpint*	uitomp(uint, mpint*);
 int	mptoi(mpint*);			/* int */
--- /n/sources/plan9/sys/man/2/mp	Mon May 24 14:37:16 2010
+++ /sys/man/2/mp	Wed Jun 26 23:40:09 2024
@@ -1,6 +1,6 @@
 .TH MP 2
 .SH NAME
-mpsetminbits, mpnew, mpfree, mpbits, mpnorm, mpcopy, mpassign, mprand, strtomp, mpfmt,mptoa, betomp, mptobe, letomp, mptole, mptoui, uitomp, mptoi, itomp, uvtomp, mptouv, vtomp, mptov, mpdigdiv, mpadd, mpsub, mpleft, mpright, mpmul, mpexp, mpmod, mpdiv, mpcmp, mpextendedgcd, mpinvert, mpsignif, mplowbits0, mpvecdigmuladd, mpvecdigmulsub, mpvecadd, mpvecsub, mpveccmp, mpvecmul, mpmagcmp, mpmagadd, mpmagsub, crtpre, crtin, crtout, crtprefree, crtresfree \- extended precision arithmetic
+mpsetminbits, mpnew, mpfree, mpbits, mpnorm, mpcopy, mpassign, mprand, strtomp, mpfmt,mptoa, betomp, mptobe, mptober, letomp, mptole, mptolel, mptoui, uitomp, mptoi, itomp, uvtomp, mptouv, vtomp, mptov, mpdigdiv, mpadd, mpsub, mpleft, mpright, mpmul, mpexp, mpmod, mpdiv, mpcmp, mpextendedgcd, mpinvert, mpsignif, mplowbits0, mpvecdigmuladd, mpvecdigmulsub, mpvecadd, mpvecsub, mpveccmp, mpvecmul, mpmagcmp, mpmagadd, mpmagsub, crtpre, crtin, crtout, crtprefree, crtresfree \- extended precision arithmetic
 .SH SYNOPSIS
 .B #include <u.h>
 .br
@@ -49,12 +49,18 @@
 int	mptobe(mpint *b, uchar *buf, uint blen, uchar **bufp)
 .PP
 .B
+void	mptober(mpint *b, uchar *buf, int blen)
+.PP
+.B
 mpint*	letomp(uchar *buf, uint blen, mpint *b)
 .PP
 .B
 int	mptole(mpint *b, uchar *buf, uint blen, uchar **bufp)
 .PP
 .B
+void	mptolel(mpint *b, uchar *buf, int blen)
+.PP
+.B
 uint	mptoui(mpint*)
 .PP
 .B
@@ -371,6 +377,24 @@
 .IR bufp .
 Sign is ignored in these conversions, i.e., the byte
 array version is always positive.
+.PP
+.I Mptober
+and
+.I mptolel
+fill
+.I blen
+lower bytes of an
+.I mpint
+into a fixed length byte array.
+.I Mptober
+fills the bytes right adjusted in big endian order so that the least
+significant byte is at
+.I buf[blen-1]
+while
+.I mptolel
+fills in little endian order; left adjusted; so that the least
+significant byte is filled into
+.IR buf[0] .
 .PP
 .IR Betomp ,
 and
diff -Nru /n/sources/plan9/sys/src/libmp/port/mkfile /sys/src/libmp/port/mkfile
--- /n/sources/plan9/sys/src/libmp/port/mkfile	Thu May 27 10:20:04 2004
+++ /sys/src/libmp/port/mkfile	Wed Jun 26 23:40:10 2024
@@ -6,7 +6,9 @@
 	mpfmt\
 	strtomp\
 	mptobe\
+	mptober\
 	mptole\
+	mptolel\
 	betomp\
 	letomp\
 	mpadd\
diff -Nru /n/sources/plan9/sys/src/libmp/port/mptobe.c /sys/src/libmp/port/mptobe.c
--- /n/sources/plan9/sys/src/libmp/port/mptobe.c	Wed Jun 26 23:28:58 2024
+++ /sys/src/libmp/port/mptobe.c	Wed Jun 26 23:40:11 2024
@@ -2,57 +2,31 @@
 #include <mp.h>
 #include "dat.h"
 
-// convert an mpint into a big endian byte array (most significant byte first)
+// convert an mpint into a big endian byte array (most significant byte first; left adjusted)
 //   return number of bytes converted
 //   if p == nil, allocate and result array
 int
 mptobe(mpint *b, uchar *p, uint n, uchar **pp)
 {
-	int i, j, suppress;
-	mpdigit x;
-	uchar *e, *s, c;
+	int m;
 
+	m = (mpsignif(b)+7)/8;
+	if(m == 0)
+		m++;
 	if(p == nil){
-		n = (b->top+1)*Dbytes;
+		n = m;
 		p = malloc(n);
 		if(p == nil)
 			sysfatal("mptobe: %r");
 		setmalloctag(p, getcallerpc(&b));
+	} else {
+		if(n < m)
+			return -1;
+		if(n > m)
+			memset(p+m, 0, n-m);
 	}
 	if(pp != nil)
 		*pp = p;
-	memset(p, 0, n);
-
-	// special case 0
-	if(b->top == 0){
-		if(n < 1)
-			return -1;
-		else
-			return 1;
-	}
-		
-	s = p;
-	e = s+n;
-	suppress = 1;
-	for(i = b->top-1; i >= 0; i--){
-		x = b->p[i];
-		for(j = Dbits-8; j >= 0; j -= 8){
-			c = x>>j;
-			if(c == 0 && suppress)
-				continue;
-			if(p >= e)
-				return -1;
-			*p++ = c;
-			suppress = 0;
-		}
-	}
-
-	// guarantee at least one byte
-	if(s == p){
-		if(p >= e)
-			return -1;
-		*p++ = 0;
-	}
-
-	return p - s;
+	mptober(b, p, m);
+	return m;
 }
diff -Nru /n/sources/plan9/sys/src/libmp/port/mptober.c /sys/src/libmp/port/mptober.c
--- /n/sources/plan9/sys/src/libmp/port/mptober.c	Wed Dec 31 19:00:00 1969
+++ /sys/src/libmp/port/mptober.c	Wed Jun 26 23:40:13 2024
@@ -0,0 +1,34 @@
+#include "os.h"
+#include <mp.h>
+#include "dat.h"
+
+void
+mptober(mpint *b, uchar *p, int n)
+{
+	int i, j, m;
+	mpdigit x;
+
+	memset(p, 0, n);
+
+	p += n;
+	m = b->top*Dbytes;
+	if(m < n)
+		n = m;
+
+	i = 0;
+	while(n >= Dbytes){
+		n -= Dbytes;
+		x = b->p[i++];
+		for(j = 0; j < Dbytes; j++){
+			*--p = x;
+			x >>= 8;
+		}
+	}
+	if(n > 0){
+		x = b->p[i];
+		for(j = 0; j < n; j++){
+			*--p = x;
+			x >>= 8;
+		}
+	}
+}
diff -Nru /n/sources/plan9/sys/src/libmp/port/mptole.c /sys/src/libmp/port/mptole.c
--- /n/sources/plan9/sys/src/libmp/port/mptole.c	Wed Jun 26 23:29:08 2024
+++ /sys/src/libmp/port/mptole.c	Wed Jun 26 23:40:13 2024
@@ -9,47 +9,21 @@
 int
 mptole(mpint *b, uchar *p, uint n, uchar **pp)
 {
-	int i, j;
-	mpdigit x;
-	uchar *e, *s;
+	int m;
 
+	m = (mpsignif(b)+7)/8;
+	if(m == 0)
+		m++;
 	if(p == nil){
-		n = (b->top+1)*Dbytes;
+		n = m;
 		p = malloc(n);
 		if(p == nil)
 			sysfatal("mptole: %r");
 		setmalloctag(p, getcallerpc(&b));
-	}
+	} else if(n < m)
+		return -1;
 	if(pp != nil)
 		*pp = p;
-	memset(p, 0, n);
-
-	// special case 0
-	if(b->top == 0){
-		if(n < 1)
-			return -1;
-		else
-			return 0;
-	}
-		
-	s = p;
-	e = s+n;
-	for(i = 0; i < b->top-1; i++){
-		x = b->p[i];
-		for(j = 0; j < Dbytes; j++){
-			if(p >= e)
-				return -1;
-			*p++ = x;
-			x >>= 8;
-		}
-	}
-	x = b->p[i];
-	while(x > 0){
-		if(p >= e)
-			return -1;
-		*p++ = x;
-		x >>= 8;
-	}
-
-	return p - s;
+	mptolel(b, p, n);
+	return m;
 }
diff -Nru /n/sources/plan9/sys/src/libmp/port/mptolel.c /sys/src/libmp/port/mptolel.c
--- /n/sources/plan9/sys/src/libmp/port/mptolel.c	Wed Dec 31 19:00:00 1969
+++ /sys/src/libmp/port/mptolel.c	Wed Jun 26 23:40:14 2024
@@ -0,0 +1,33 @@
+#include "os.h"
+#include <mp.h>
+#include "dat.h"
+
+void
+mptolel(mpint *b, uchar *p, int n)
+{
+	int i, j, m;
+	mpdigit x;
+
+	memset(p, 0, n);
+
+	m = b->top*Dbytes;
+	if(m < n)
+		n = m;
+
+	i = 0;
+	while(n >= Dbytes){
+		n -= Dbytes;
+		x = b->p[i++];
+		for(j = 0; j < Dbytes; j++){
+			*p++ = x;
+			x >>= 8;
+		}
+	}
+	if(n > 0){
+		x = b->p[i];
+		for(j = 0; j < n; j++){
+			*p++ = x;
+			x >>= 8;
+		}
+	}
+}
diff -Nru /n/sources/plan9/sys/src/ape/lib/mp/port/mkfile /sys/src/ape/lib/mp/port/mkfile
--- /n/sources/plan9/sys/src/ape/lib/mp/port/mkfile	Tue May 28 21:27:28 2013
+++ /sys/src/ape/lib/mp/port/mkfile	Wed Jun 26 23:42:10 2024
@@ -8,7 +8,9 @@
 	mpfmt\
 	strtomp\
 	mptobe\
+	mptober\
 	mptole\
+	mptolel\
 	betomp\
 	letomp\
 	mpadd\