diff --git a/bootstrap/unix-44/Out.c b/bootstrap/unix-44/Out.c
index dc9ab60c..090b2c81 100644
--- a/bootstrap/unix-44/Out.c
+++ b/bootstrap/unix-44/Out.c
@@ -354,7 +354,7 @@ void Out_DumpHeap (void)
 		Out_Hex(c->reserved, 1);
 		Out_Ln();
 		baddr = (ADDRESS)&c->firstblock;
-		while (baddr < c->end) {
+		while (c->end - baddr > 0) {
 			Out_String((CHAR*)"  Block at:   ", 15);
 			Out_Hex(baddr, 1);
 			Out_Ln();
diff --git a/bootstrap/unix-48/Out.c b/bootstrap/unix-48/Out.c
index dc9ab60c..090b2c81 100644
--- a/bootstrap/unix-48/Out.c
+++ b/bootstrap/unix-48/Out.c
@@ -354,7 +354,7 @@ void Out_DumpHeap (void)
 		Out_Hex(c->reserved, 1);
 		Out_Ln();
 		baddr = (ADDRESS)&c->firstblock;
-		while (baddr < c->end) {
+		while (c->end - baddr > 0) {
 			Out_String((CHAR*)"  Block at:   ", 15);
 			Out_Hex(baddr, 1);
 			Out_Ln();
diff --git a/bootstrap/unix-88/Out.c b/bootstrap/unix-88/Out.c
index 5b315327..d0223799 100644
--- a/bootstrap/unix-88/Out.c
+++ b/bootstrap/unix-88/Out.c
@@ -354,7 +354,7 @@ void Out_DumpHeap (void)
 		Out_Hex(c->reserved, 1);
 		Out_Ln();
 		baddr = (ADDRESS)&c->firstblock;
-		while (baddr < c->end) {
+		while (c->end - baddr > 0) {
 			Out_String((CHAR*)"  Block at:   ", 15);
 			Out_Hex(baddr, 1);
 			Out_Ln();
diff --git a/bootstrap/windows-48/Out.c b/bootstrap/windows-48/Out.c
index f215ffaf..ef5d74e5 100644
--- a/bootstrap/windows-48/Out.c
+++ b/bootstrap/windows-48/Out.c
@@ -354,7 +354,7 @@ void Out_DumpHeap (void)
 		Out_Hex(c->reserved, 1);
 		Out_Ln();
 		baddr = (ADDRESS)&c->firstblock;
-		while (baddr < c->end) {
+		while (c->end - baddr > 0) {
 			Out_String((CHAR*)"  Block at:   ", 15);
 			Out_Hex(baddr, 1);
 			Out_Ln();
diff --git a/bootstrap/windows-88/Out.c b/bootstrap/windows-88/Out.c
index e8d8713a..bbb5de28 100644
--- a/bootstrap/windows-88/Out.c
+++ b/bootstrap/windows-88/Out.c
@@ -354,7 +354,7 @@ void Out_DumpHeap (void)
 		Out_Hex(c->reserved, 1);
 		Out_Ln();
 		baddr = (ADDRESS)&c->firstblock;
-		while (baddr < c->end) {
+		while (c->end - baddr > 0) {
 			Out_String((CHAR*)"  Block at:   ", 15);
 			Out_Hex(baddr, 1);
 			Out_Ln();