diff --git a/blink/machine.c b/blink/machine.c
index ad309eb2..af8211dc 100644
--- a/blink/machine.c
+++ b/blink/machine.c
@@ -1046,40 +1046,40 @@ static u64 AluPopcnt(u64 x, struct Machine *m) {
   return popcount(x);
 }
 
-static u64 AluLzcnt(u64 x, struct Machine *m, int bits) {
+static u64 AluTzcnt(u64 x, struct Machine *m, int bits) {
   u64 r = x ? bsf(x) : bits;
   m->flags = SetFlag(m->flags, FLAGS_CF, !x);
   m->flags = SetFlag(m->flags, FLAGS_ZF, !r);
   return r;
 }
-static u64 AluLzcnt64(u64 x, struct Machine *m) {
-  return AluLzcnt(x, m, 64);
+static u64 AluTzcnt64(u64 x, struct Machine *m) {
+  return AluTzcnt(x, m, 64);
 }
-static u64 AluLzcnt32(u64 x, struct Machine *m) {
-  return AluLzcnt(x, m, 32);
+static u64 AluTzcnt32(u64 x, struct Machine *m) {
+  return AluTzcnt(x, m, 32);
 }
-static u64 AluLzcnt16(u64 x, struct Machine *m) {
-  return AluLzcnt(x, m, 16);
+static u64 AluTzcnt16(u64 x, struct Machine *m) {
+  return AluTzcnt(x, m, 16);
 }
 static u64 AluBsf(u64 x, struct Machine *m) {
   m->flags = SetFlag(m->flags, FLAGS_ZF, !x);
   return x ? bsf(x) : 0;
 }
 
-static u64 AluTzcnt(u64 x, struct Machine *m, int bits) {
-  u64 r = x ? bsr(x) : bits;
+static u64 AluLzcnt(u64 x, struct Machine *m, int bits) {
+  u64 r = x ? bits - 1 - bsr(x) : bits;
   m->flags = SetFlag(m->flags, FLAGS_CF, !x);
   m->flags = SetFlag(m->flags, FLAGS_ZF, !r);
   return r;
 }
-static u64 AluTzcnt64(u64 x, struct Machine *m) {
-  return AluTzcnt(x, m, 64);
+static u64 AluLzcnt64(u64 x, struct Machine *m) {
+  return AluLzcnt(x, m, 64);
 }
-static u64 AluTzcnt32(u64 x, struct Machine *m) {
-  return AluTzcnt(x, m, 32);
+static u64 AluLzcnt32(u64 x, struct Machine *m) {
+  return AluLzcnt(x, m, 32);
 }
-static u64 AluTzcnt16(u64 x, struct Machine *m) {
-  return AluTzcnt(x, m, 16);
+static u64 AluLzcnt16(u64 x, struct Machine *m) {
+  return AluLzcnt(x, m, 16);
 }
 static u64 AluBsr(u64 x, struct Machine *m) {
   m->flags = SetFlag(m->flags, FLAGS_ZF, !x);
@@ -1105,11 +1105,11 @@ static void OpBsf(P) {
   u64 (*op)(u64, struct Machine *);
   if (Rep(rde) == 3) {
     if (Rexw(rde)) {
-      op = AluLzcnt64;
+      op = AluTzcnt64;
     } else if (!Osz(rde)) {
-      op = AluLzcnt32;
+      op = AluTzcnt32;
     } else {
-      op = AluLzcnt16;
+      op = AluTzcnt16;
     }
   } else {
     op = AluBsf;
@@ -1121,11 +1121,11 @@ static void OpBsr(P) {
   u64 (*op)(u64, struct Machine *);
   if (Rep(rde) == 3) {
     if (Rexw(rde)) {
-      op = AluTzcnt64;
+      op = AluLzcnt64;
     } else if (!Osz(rde)) {
-      op = AluTzcnt32;
+      op = AluLzcnt32;
     } else {
-      op = AluTzcnt16;
+      op = AluLzcnt16;
     }
   } else {
     op = AluBsr;