--- a/src/m/ibmps2-aix.h	Mon Aug 13 11:19:22 2007 +0200
+++ b/src/m/ibmps2-aix.h	Mon Aug 13 11:20:41 2007 +0200
@@ -30,6 +30,11 @@
   work with certain new X window managers, and may be suboptimal.
 NOTE-END */
 
+/* Define WORD_MACHINE if addresses and such have
+ * to be corrected before they can be used as byte counts.  */
+
+/* #define WORD_MACHINE */
+
 /* Now define a symbol for the cpu type, if your compiler
    does not define it automatically:
    Ones defined so far include vax, m68000, ns16000, pyramid,
@@ -80,6 +85,11 @@
 #define DATA_START 0x00800000
 #define DATA_END 0
 
+/* The data segment in this machine always starts at address 0x00800000.
+   An address of data cannot be stored correctly in a Lisp object;
+   we always lose the high bits.  We must tell XPNTR to add them back.  */
+
+#define DATA_SEG_BITS 0x00800000
 #endif
 
 #if 0 /* I refuse to promulgate a recommendation that would make