diff --git a/modules/pdp10/lib/cpuops.js b/modules/pdp10/lib/cpuops.js
index fae65d6f0..75f914003 100644
--- a/modules/pdp10/lib/cpuops.js
+++ b/modules/pdp10/lib/cpuops.js
@@ -1686,7 +1686,7 @@ PDP10.opASHC = function(op, acc)
                 /*
                  * For this right shift of 1-35 bits, determine the value of bits shifted in from the left.
                  */
-                bits = (wLeft > PDP10.INT_MASK? PDP10.WORD_LIMIT - Math.pow(2, 36 - s) : 0);
+                bits = (wLeft > PDP10.INT_MASK? PDP10.WORD_LIMIT - Math.pow(2, 36 + s) : 0);
                 /*
                  * The bits that we add to wRight from wLeft must be shifted right one additional bit, because
                  * they must "skip over" the sign bit of wRight.  This means we must zero the sign bit of wRight,
diff --git a/modules/shared/bin/int36 b/modules/shared/bin/int36
index 0e6daf42e..3e0670e93 100644
--- a/modules/shared/bin/int36
+++ b/modules/shared/bin/int36
@@ -179,6 +179,9 @@ test("lsh 3");
 test("lsh -3");
 test("rot 6");
 test("rot -6");
+test("set 0o112233445566 0o123456123456");
+test("rot 18");
+test("ash -3");
 
 repl.start({
     prompt: "int36> ",
diff --git a/modules/shared/lib/int36.js b/modules/shared/lib/int36.js
index ab4c4237a..77f44ee49 100644
--- a/modules/shared/lib/int36.js
+++ b/modules/shared/lib/int36.js
@@ -289,7 +289,7 @@ class Int36 {
         if (radix == 8) {
             var s = Int36.octal(value);
             if (extended) {
-                s = Int36.octal(extended) + ',' + s;
+                s = Int36.octal(extended) + ' ' + s;
             }
             if (this.remainder) {
                 s += ':' + Int36.octal(this.remainder);
@@ -843,7 +843,7 @@ class Int36 {
                         /*
                          * For this right shift of 1-35 bits, determine the value of bits shifted in from the left.
                          */
-                        bits = (wLeft > Int36.INT_MASK? Int36.WORD_LIMIT - Math.pow(2, 36 - s) : 0);
+                        bits = (wLeft > Int36.INT_MASK? Int36.WORD_LIMIT - Math.pow(2, 36 + s) : 0);
                         /*
                          * The bits that we add to wRight from wLeft must be shifted right one additional bit, because
                          * they must "skip over" the sign bit of wRight.  This means we must zero the sign bit of wRight,
@@ -1213,8 +1213,14 @@ class Int36 {
      */
     static octal(value)
     {
-        if (value < 0) value += Int36.WORD_LIMIT;
-        return ("00000000000" + value.toString(8)).slice(-12);
+        if (value < 0) {
+            value += Int36.WORD_LIMIT;
+        }
+        var s = value.toString(8);
+        if (value >= 0 && !Math.trunc(value / Int36.WORD_LIMIT)) {
+            s = "0o" + ("000000000000" + s).slice(-12);
+        }
+        return s;
     }
 
     /**
@@ -1238,7 +1244,7 @@ class Int36 {
         }
         var value = Math.trunc(Math.abs(num)) % Math.pow(2, bits);
         if (DEBUG && num !== value) {
-            console.log("Int36.validate(" + num + " out of range, truncated to " + value + ")");
+            console.log("Int36.validate(" + Int36.octal(num) + " out of range, truncated to " + Int36.octal(value) + ")");
         }
         return value;
     }
diff --git a/versions/pdpjs/1.34.2/pdp10-dbg.js b/versions/pdpjs/1.34.2/pdp10-dbg.js
index e44c685e3..05a6b88db 100644
--- a/versions/pdpjs/1.34.2/pdp10-dbg.js
+++ b/versions/pdpjs/1.34.2/pdp10-dbg.js
@@ -111,7 +111,7 @@ function(a){this.b(a)},function(a){this.b(a)},function(a){this.b(a)},function(a)
 this.g(b)))},function(a,b){a=Od(this,this.g(this.f));this.j(this.f,a);b&&this.j(b,a)},function(a,b){this.j(b,this.abs(this.g(this.f)))},function(a,b){this.j(b,this.f)},function(a,b){this.j(this.f,this.abs(this.g(b)))},function(a,b){a=this.abs(this.g(this.f));this.j(this.f,a);b&&this.j(b,a)},function(a){this.b(a)},function(a){this.b(a)},function(a){this.b(a)},function(a){this.b(a)},function(a){this.b(a)},function(a){this.b(a)},function(a){this.b(a)},function(a){this.b(a)},function(a){this.b(a)},function(a){this.b(a)},
 function(a){this.b(a)},function(a){this.b(a)},function(a){this.b(a)},function(a){this.b(a)},function(a){this.b(a)},function(a){this.b(a)},function(a,b){var c=(this.f<<14>>14)%256;if(c){a=this.g(b);var d=a>I?-(H-a):a;0<c?(35<=c?(d=0>d?F:0,c=Tb):(d=d*Math.pow(2,c)%F,c=F-Math.pow(2,35-c)),a<=I?a+c>I&&(this.w|=131072):a-c<=I&&(this.w|=131072)):d=-35>=c?0>d?-1:0:Math.trunc(d/Math.pow(2,-c));a=0>d?d+H:d;this.j(b,a)}},function(a,b){if(a=(this.f<<14>>14)%36){var c=this.g(b);0>a&&(a=36+a);c=c*Math.pow(2,a)%
 H+Math.trunc(c/Math.pow(2,36-a));this.j(b,c)}},function(a,b){if(a=(this.f<<14>>14)%256){var c=this.g(b),c=0<a?36<=a?0:c*Math.pow(2,a)%H:-36>=a?0:Math.trunc(c/Math.pow(2,-a));this.j(b,c)}},function(a){this.b(a)},function(a,b){if(a=(this.f<<14>>14)%256){var c,d=this.g(b),e=this.g(b+1&15);if(0<a){var g=d;if(36<=a){if(0<d&&d<F||d>Tb&&d<G)this.w|=131072;if(71<=a){if(0<e&&e<F||e>Tb&&e<G)this.w|=131072;d=0}else d=e*Math.pow(2,a-35)%F,c=F-Math.pow(2,70-a),g<=I?e+c>I&&(this.w|=131072):e-c<=I&&(this.w|=131072);
-e=0;g>Tb&&(d+=F,e+=F)}else d=d*Math.pow(2,a)%F+Math.trunc(e%F/Math.pow(2,35-a)),e=e*Math.pow(2,a)%F,c=F-Math.pow(2,35-a),g<=I?g+c>I&&(this.w|=131072):(g-c<=I&&(this.w|=131072),d+=F,e+=F)}else-36>=a?(e=-72>=a?d>Tb?G:0:Math.trunc(d%F/Math.pow(2,-a-35)),d<=Tb?d=0:(d=G,e+=F)):(c=d>Tb?H-Math.pow(2,36-a):0,e=Math.trunc(e%F/Math.pow(2,-a))+d%F*Math.pow(2,35+a)%F,d=Math.trunc(d/Math.pow(2,-a))+c,d>Tb&&(e+=F));this.j(b,d);this.j(b+1&15,e)}},function(a,b){if(a=(this.f<<14>>14)%72){var c=this.g(b),d=this.g(b+
+e=0;g>Tb&&(d+=F,e+=F)}else d=d*Math.pow(2,a)%F+Math.trunc(e%F/Math.pow(2,35-a)),e=e*Math.pow(2,a)%F,c=F-Math.pow(2,35-a),g<=I?g+c>I&&(this.w|=131072):(g-c<=I&&(this.w|=131072),d+=F,e+=F)}else-36>=a?(e=-72>=a?d>Tb?G:0:Math.trunc(d%F/Math.pow(2,-a-35)),d<=Tb?d=0:(d=G,e+=F)):(c=d>Tb?H-Math.pow(2,36+a):0,e=Math.trunc(e%F/Math.pow(2,-a))+d%F*Math.pow(2,35+a)%F,d=Math.trunc(d/Math.pow(2,-a))+c,d>Tb&&(e+=F));this.j(b,d);this.j(b+1&15,e)}},function(a,b){if(a=(this.f<<14>>14)%72){var c=this.g(b),d=this.g(b+
 1&15),e=c;0>a&&(a=72+a);36>a?(c=c*Math.pow(2,a)%H+Math.trunc(d/Math.pow(2,36-a)),d=d*Math.pow(2,a)%H+Math.trunc(e/Math.pow(2,36-a))):(c=d*Math.pow(2,a-36)%H+Math.trunc(c/Math.pow(2,72-a)),d=e*Math.pow(2,a-36)%H+Math.trunc(d/Math.pow(2,72-a)));this.j(b,c);this.j(b+1&15,d)}},function(a,b){if(a=(this.f<<14>>14)%256){var c=this.g(b),d=this.g(b+1&15);0<a?36<=a?(c=72<=a?0:d*Math.pow(2,a-36)%H,d=0):(c=c*Math.pow(2,a)%H+Math.trunc(d/Math.pow(2,36-a)),d=d*Math.pow(2,a)%H):-36>=a?(d=-72>=a?0:Math.trunc(c/Math.pow(2,
 -a-36)),c=0):(d=Math.trunc(d/Math.pow(2,-a))+c*Math.pow(2,36+a)%H,c=Math.trunc(c/Math.pow(2,-a)));this.j(b,c);this.j(b+1&15,d)}},P,function(a,b){a=this.g(b);this.j(b,this.g(this.f));this.j(this.f,a)},function(a,b){a=!1;for(var c=this.g(b),d=c/B|0,c=c&A;!a;)this.j(c,this.g(d)),c==this.f&&(a=!0),d=d+1&A,c=c+1&A,this.v.K||(this.j(b,d*B+c),a||Nd(this,-1),a=!0)},function(a){this.b(a)},function(a){this.b(a)},function(a){this.b(a)},function(a){this.b(a)},function(a){this.b(a)},P,function(a){this.b(a)},function(a,
 b){a=this.g(b);a+=262145;this.j(a&A,this.g(this.f));a>=H&&(a-=H);a/B|0||(this.w|=262144);this.j(b,a)},function(a,b){a=this.g(b);var c=this.g(a&A);this.j(this.f,c);this.f==b&&(a=c);a-=262145;0>a&&(a+=H);(a/B|0)==A&&(this.w|=262144);this.j(b,a)},function(a){this.b(a)},function(a){this.b(a)},function(a){this.b(a)},function(a){this.b(a)},function(a){this.b(a)},function(a){this.b(a)},function(a){this.b(a)},function(a){this.b(a)},function(a){this.b(a)},function(a){this.b(a)},function(a){this.b(a)},function(a){this.b(a)},
diff --git a/versions/pdpjs/1.34.2/pdp10.js b/versions/pdpjs/1.34.2/pdp10.js
index 17fda825e..801494578 100644
--- a/versions/pdpjs/1.34.2/pdp10.js
+++ b/versions/pdpjs/1.34.2/pdp10.js
@@ -106,7 +106,7 @@ function(a){this.a(a)},function(a){this.a(a)},function(a){this.a(a)},function(a)
 this.c(b)))},function(a,b){a=gc(this,this.c(this.b));this.f(this.b,a);b&&this.f(b,a)},function(a,b){this.f(b,this.abs(this.c(this.b)))},function(a,b){this.f(b,this.b)},function(a,b){this.f(this.b,this.abs(this.c(b)))},function(a,b){a=this.abs(this.c(this.b));this.f(this.b,a);b&&this.f(b,a)},function(a){this.a(a)},function(a){this.a(a)},function(a){this.a(a)},function(a){this.a(a)},function(a){this.a(a)},function(a){this.a(a)},function(a){this.a(a)},function(a){this.a(a)},function(a){this.a(a)},function(a){this.a(a)},
 function(a){this.a(a)},function(a){this.a(a)},function(a){this.a(a)},function(a){this.a(a)},function(a){this.a(a)},function(a){this.a(a)},function(a,b){var c=(this.b<<14>>14)%256;if(c){a=this.c(b);var d=a>O?-(N-a):a;0<c?(35<=c?(d=0>d?L:0,c=K):(d=d*Math.pow(2,c)%L,c=L-Math.pow(2,35-c)),a<=O?a+c>O&&(this.h|=131072):a-c<=O&&(this.h|=131072)):d=-35>=c?0>d?-1:0:Math.trunc(d/Math.pow(2,-c));a=0>d?d+N:d;this.f(b,a)}},function(a,b){if(a=(this.b<<14>>14)%36){var c=this.c(b);0>a&&(a=36+a);c=c*Math.pow(2,a)%
 N+Math.trunc(c/Math.pow(2,36-a));this.f(b,c)}},function(a,b){if(a=(this.b<<14>>14)%256){var c=this.c(b),c=0<a?36<=a?0:c*Math.pow(2,a)%N:-36>=a?0:Math.trunc(c/Math.pow(2,-a));this.f(b,c)}},function(a){this.a(a)},function(a,b){if(a=(this.b<<14>>14)%256){var c,d=this.c(b),e=this.c(b+1&15);if(0<a){var f=d;if(36<=a){if(0<d&&d<L||d>K&&d<M)this.h|=131072;if(71<=a){if(0<e&&e<L||e>K&&e<M)this.h|=131072;d=0}else d=e*Math.pow(2,a-35)%L,c=L-Math.pow(2,70-a),f<=O?e+c>O&&(this.h|=131072):e-c<=O&&(this.h|=131072);
-e=0;f>K&&(d+=L,e+=L)}else d=d*Math.pow(2,a)%L+Math.trunc(e%L/Math.pow(2,35-a)),e=e*Math.pow(2,a)%L,c=L-Math.pow(2,35-a),f<=O?f+c>O&&(this.h|=131072):(f-c<=O&&(this.h|=131072),d+=L,e+=L)}else-36>=a?(e=-72>=a?d>K?M:0:Math.trunc(d%L/Math.pow(2,-a-35)),d<=K?d=0:(d=M,e+=L)):(c=d>K?N-Math.pow(2,36-a):0,e=Math.trunc(e%L/Math.pow(2,-a))+d%L*Math.pow(2,35+a)%L,d=Math.trunc(d/Math.pow(2,-a))+c,d>K&&(e+=L));this.f(b,d);this.f(b+1&15,e)}},function(a,b){if(a=(this.b<<14>>14)%72){var c=this.c(b),d=this.c(b+1&15),
+e=0;f>K&&(d+=L,e+=L)}else d=d*Math.pow(2,a)%L+Math.trunc(e%L/Math.pow(2,35-a)),e=e*Math.pow(2,a)%L,c=L-Math.pow(2,35-a),f<=O?f+c>O&&(this.h|=131072):(f-c<=O&&(this.h|=131072),d+=L,e+=L)}else-36>=a?(e=-72>=a?d>K?M:0:Math.trunc(d%L/Math.pow(2,-a-35)),d<=K?d=0:(d=M,e+=L)):(c=d>K?N-Math.pow(2,36+a):0,e=Math.trunc(e%L/Math.pow(2,-a))+d%L*Math.pow(2,35+a)%L,d=Math.trunc(d/Math.pow(2,-a))+c,d>K&&(e+=L));this.f(b,d);this.f(b+1&15,e)}},function(a,b){if(a=(this.b<<14>>14)%72){var c=this.c(b),d=this.c(b+1&15),
 e=c;0>a&&(a=72+a);36>a?(c=c*Math.pow(2,a)%N+Math.trunc(d/Math.pow(2,36-a)),d=d*Math.pow(2,a)%N+Math.trunc(e/Math.pow(2,36-a))):(c=d*Math.pow(2,a-36)%N+Math.trunc(c/Math.pow(2,72-a)),d=e*Math.pow(2,a-36)%N+Math.trunc(d/Math.pow(2,72-a)));this.f(b,c);this.f(b+1&15,d)}},function(a,b){if(a=(this.b<<14>>14)%256){var c=this.c(b),d=this.c(b+1&15);0<a?36<=a?(c=72<=a?0:d*Math.pow(2,a-36)%N,d=0):(c=c*Math.pow(2,a)%N+Math.trunc(d/Math.pow(2,36-a)),d=d*Math.pow(2,a)%N):-36>=a?(d=-72>=a?0:Math.trunc(c/Math.pow(2,
 -a-36)),c=0):(d=Math.trunc(d/Math.pow(2,-a))+c*Math.pow(2,36+a)%N,c=Math.trunc(c/Math.pow(2,-a)));this.f(b,c);this.f(b+1&15,d)}},U,function(a,b){a=this.c(b);this.f(b,this.c(this.b));this.f(this.b,a)},function(a,b){a=!1;for(var c=this.c(b),d=c/J|0,c=c&I;!a;)this.f(c,this.c(d)),c==this.b&&(a=!0),d=d+1&I,c=c+1&I,this.g.A||(this.f(b,d*J+c),a||fc(this),a=!0)},function(a){this.a(a)},function(a){this.a(a)},function(a){this.a(a)},function(a){this.a(a)},function(a){this.a(a)},U,function(a){this.a(a)},function(a,
 b){a=this.c(b);a+=262145;this.f(a&I,this.c(this.b));a>=N&&(a-=N);a/J|0||(this.h|=262144);this.f(b,a)},function(a,b){a=this.c(b);var c=this.c(a&I);this.f(this.b,c);this.b==b&&(a=c);a-=262145;0>a&&(a+=N);(a/J|0)==I&&(this.h|=262144);this.f(b,a)},function(a){this.a(a)},function(a){this.a(a)},function(a){this.a(a)},function(a){this.a(a)},function(a){this.a(a)},function(a){this.a(a)},function(a){this.a(a)},function(a){this.a(a)},function(a){this.a(a)},function(a){this.a(a)},function(a){this.a(a)},function(a){this.a(a)},