This is Kees Visser's version, implementing 4-4.

mach/pdp/cg/mach.h

@@ -0,0 +1,46 @@
+/* $Header$ */
+
+/* The next define switches between codegeneration for an ACK assembler
+ * or for the standard UNIX V7 assembler.
+ * If on code is generated for the ACK assembler.
+ */
+/* #define ACK_ASS	/* code for ACK assembler */
+
+#ifdef ACK_ASS
+#define COMMENTCHAR '!'
+#define ex_ap(y)	fprintf(codefile,".extern %s\n",y)
+#else
+#define COMMENTCHAR '/'
+#define ex_ap(y)	fprintf(codefile,".globl %s\n",y)
+#endif
+#define in_ap(y)	/* nothing */
+
+#define newplb(x)	doplb(x)
+#define newilb(x)	fprintf(codefile,"%s:\n",x)
+#define newdlb(x)	fprintf(codefile,"%s:\n",x)
+#ifdef ACK_ASS
+#define newlbss(l,x)	fprintf(codefile,"%s:.space 0%o\n",l,x);
+#else
+#define newlbss(l,x)	fprintf(codefile,"%s:.=.+0%o\n",l,x);
+#endif
+
+#define cst_fmt		"$0%o"
+#define off_fmt		"0%o"
+#define ilb_fmt		"I%03x%x"
+#define dlb_fmt		"_%d"
+#define	hol_fmt		"hol%d"
+
+#define hol_off		"0%o+hol%d"
+
+#ifdef ACK_ASS
+#define con_cst(x)	fprintf(codefile,".short 0%o\n",x)
+#define con_ilb(x)	fprintf(codefile,".short %s\n",x)
+#define con_dlb(x)	fprintf(codefile,".short %s\n",x)
+#else
+#define con_cst(x)	fprintf(codefile,"0%o\n",x)
+#define con_ilb(x)	fprintf(codefile,"%s\n",x)
+#define con_dlb(x)	fprintf(codefile,"%s\n",x)
+#endif
+
+#define id_first	'_'
+#define BSS_INIT	0