From 110c78b309efa4d9379ead22c639cda9b7f067b3 Mon Sep 17 00:00:00 2001
From: Vitor Santos Costa <vsc@Vitors-MacBook-Pro.local>
Date: Mon, 9 Jan 2012 23:27:47 +0000
Subject: [PATCH] add dereferencing macro.

---
 H/amiops.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/H/amiops.h b/H/amiops.h
index d8abe7460..f6a8e62de 100644
--- a/H/amiops.h
+++ b/H/amiops.h
@@ -44,6 +44,18 @@ Dereferencing macros
                    (D) = *(CELL *)(D);                       \
 		   } while (Unsigned(A) != (D))
 
+#define do_derefa(D,A,LabelUnk,LabelDone)		  \
+                (D) = *(CELL *)(A);                       \
+		if (IsNonVarTerm(D))    goto LabelDone;	     \
+		goto LabelUnk; \
+		do {                                         \
+                   (A) = (CELL *)(D);                        \
+                   (D) = *(CELL *)(D);                       \
+                   if(!IsVarTerm(D)) goto LabelDone;       \
+		LabelUnk: ;				   \
+		} while (Unsigned(A) != (D));\
+             LabelDone:
+
 #define derefa_body(D,A,LabelUnk,LabelNonVar)                \
 		do {                                         \
                    (A) = (CELL *)(D);                        \