diff --git a/Makefile b/Makefile
index d36bb83fb7..b3db92479c 100644
--- a/Makefile
+++ b/Makefile
@@ -9,7 +9,7 @@ DISK_IMAGE = Factor-$(VERSION).dmg
 LIBPATH = -L/usr/X11R6/lib
 
 ifdef DEBUG
-	CFLAGS = -g
+	CFLAGS = -g -std=gnu99
 	STRIP = touch
 else
 	CFLAGS = -Wall -O3 -ffast-math -std=gnu99 $(SITE_CFLAGS)
diff --git a/core/compiler/amd64/architecture.factor b/core/compiler/amd64/architecture.factor
index e8aeffbce6..43d833531c 100644
--- a/core/compiler/amd64/architecture.factor
+++ b/core/compiler/amd64/architecture.factor
@@ -46,5 +46,4 @@ M: float-regs fastcall-regs vregs ;
 : %prologue ( n -- )
     \ stack-reserve set stack-reg stack-increment SUB ;
 
-: %epilogue ( -- )
-    stack-reg stack-increment ADD ;
+: %epilogue ( -- ) stack-reg stack-increment ADD ;
diff --git a/core/compiler/test/stack-trace.factor b/core/compiler/test/stack-trace.factor
index de1c5c828c..daf8afacc9 100644
--- a/core/compiler/test/stack-trace.factor
+++ b/core/compiler/test/stack-trace.factor
@@ -1,12 +1,28 @@
 IN: temporary
-USING: errors compiler test namespaces sequences kernel-internals ;
+USING: errors compiler test namespaces sequences
+kernel-internals kernel math ;
+
+: nice-stack-trace
+    error-stack-trace get symbolic-stack-trace [ second ] map ;
 
 : foo 3 throw 7 ;
 : bar foo 4 ;
 : baz bar 5 ;
 \ baz compile
 [ 3 ] [ [ baz ] catch ] unit-test
-[ { foo bar baz } ] [
-    error-stack-trace get symbolic-stack-trace
-    [ second ] map [ ] subset
+[ { foo bar baz } ] [ nice-stack-trace ] unit-test
+
+: bleh [ 3 + ] map [ 0 > ] subset ;
+\ bleh compile
+
+: stack-trace-contains? nice-stack-trace memq? ;
+    
+[ t ] [
+    [ { 1 "hi" } bleh ] catch drop \ + stack-trace-contains?
+] unit-test
+    
+[ f t ] [
+    [ { C{ 1 2 } } bleh ] catch drop
+    \ + stack-trace-contains?
+    \ > stack-trace-contains?
 ] unit-test
diff --git a/vm/cpu-amd64.S b/vm/cpu-amd64.S
index eb3c1009ac..9d4946ae2c 100644
--- a/vm/cpu-amd64.S
+++ b/vm/cpu-amd64.S
@@ -9,5 +9,4 @@ void *native_stack_pointer(void) */
 	.globl MANGLE(native_stack_pointer)
 MANGLE(native_stack_pointer):
 	mov %rsp,%rax
-	add $8,%rax
 	ret
diff --git a/vm/cpu-amd64.h b/vm/cpu-amd64.h
index 99318ab687..55d845c48b 100644
--- a/vm/cpu-amd64.h
+++ b/vm/cpu-amd64.h
@@ -8,10 +8,7 @@ INLINE void flush_icache(CELL start, CELL len) {}
 
 void *native_stack_pointer(void);
 
-typedef struct _F_STACK_FRAME {
-	struct _F_STACK_FRAME *previous;
-	CELL return_address;
-} F_STACK_FRAME;
+typedef CELL F_STACK_FRAME;
 
-#define PREVIOUS_FRAME(frame) (frame->previous)
-#define RETURN_ADDRESS(frame) (frame->return_address)
+#define PREVIOUS_FRAME(frame) (frame + 1)
+#define RETURN_ADDRESS(frame) (*(frame))
diff --git a/vm/run.c b/vm/run.c
index a247ab9327..1cf4a55c2e 100644
--- a/vm/run.c
+++ b/vm/run.c
@@ -276,14 +276,16 @@ CELL allot_native_stack_trace(void)
 			GROWABLE_ADD(array,cell);
 		}
 
-		if(PREVIOUS_FRAME(frame) <= frame)
+		F_STACK_FRAME *prev = PREVIOUS_FRAME(frame);
+
+		if(prev <= frame)
 		{
 			fprintf(stderr,"*** Unusual C stack layout (why?)\n");
 			fflush(stderr);
 			break;
 		}
 
-		frame = PREVIOUS_FRAME(frame);
+		frame = prev;
 	}
 
 	GROWABLE_TRIM(array);
diff --git a/vm/types.c b/vm/types.c
index 387d12b085..bbeb90ff8b 100644
--- a/vm/types.c
+++ b/vm/types.c
@@ -46,8 +46,13 @@ F_ARRAY *allot_array(CELL type, F_FIXNUM capacity, CELL fill)
 /* size is in bytes this time */
 F_ARRAY *allot_byte_array(F_FIXNUM size)
 {
-	F_FIXNUM byte_size = (F_FIXNUM)(size + sizeof(CELL) - 1)
-		/ (F_FIXNUM)sizeof(CELL);
+	if(size < 0)
+	{
+		general_error(ERROR_NEGATIVE_ARRAY_SIZE,allot_integer(size),F,true);
+		return NULL;
+	}
+
+	CELL byte_size = (size + sizeof(CELL) - 1) / sizeof(CELL);
 	return allot_array(BYTE_ARRAY_TYPE,byte_size,0);
 }