diff --git a/mach/6500/as/mach0.c b/mach/6500/as/mach0.c
new file mode 100644
index 000000000..7cf4e3b77
--- /dev/null
+++ b/mach/6500/as/mach0.c
@@ -0,0 +1,10 @@
+#define DUK
+#define RCSID0 "$Header$"
+
+/*
+ * Mostek 6500 options.
+ */
+#define	THREE_PASS	/* Distinguish short and long branches. */
+#define	LISTING		/* Enable listing facilities. */
+#define RELOCATION	/* Produce relocation information. */
+#define NOLD		/* Output must be fed into separate linker. */
diff --git a/mach/6500/as/mach1.c b/mach/6500/as/mach1.c
new file mode 100644
index 000000000..118df68f7
--- /dev/null
+++ b/mach/6500/as/mach1.c
@@ -0,0 +1,7 @@
+#define RCSID1 "$Header$"
+
+/*
+ * Mostek 6500 dependent C declarations.
+ */
+
+#define fits_zeropage(x)	(lowb(x) == (int)(x))
diff --git a/mach/6500/as/mach2.c b/mach/6500/as/mach2.c
new file mode 100644
index 000000000..b1bc54986
--- /dev/null
+++ b/mach/6500/as/mach2.c
@@ -0,0 +1,28 @@
+#define RCSID2 "$Header$"
+
+/*
+ * Mostek 6500 tokens.
+ */
+
+%token <y_word> A
+%token <y_word> X
+%token <y_word> Y
+%token <y_word> EXTENSION
+%token <y_word> ADDOP
+%token <y_word> ROLOP
+%token <y_word> BRAOP
+%token <y_word> BITOP
+%token <y_word> NOPOP
+%token <y_word> CPXOP
+%token <y_word> INCOP
+%token <y_word> JMPOP
+%token <y_word> JSROP
+%token <y_word> LDXOP
+%token <y_word> LDYOP
+%token <y_word> STXOP
+%token <y_word> STYOP
+%token <y_word> PSEU
+
+%type <y_word> addop
+
+%nonassoc EXTENSION
diff --git a/mach/6500/as/mach3.c b/mach/6500/as/mach3.c
new file mode 100644
index 000000000..ce701582b
--- /dev/null
+++ b/mach/6500/as/mach3.c
@@ -0,0 +1,69 @@
+#define RCSID3 "$Header$"
+
+/*
+ * Mostek 6500 keywords
+ */
+
+0,	EXTENSION,	0,		".l",
+0,	EXTENSION,	8,		".h",
+0,	A,		0,		"a",
+0,	X,		0,		"x",
+0,	Y,		0,		"y",
+0,	ADDOP,		0x60,		"adc",
+0,	ADDOP,		0x20,		"and",
+0,	ADDOP,		0xC0,		"cmp",
+0,	ADDOP,		0x40,		"eor",
+0,	ADDOP,		0xA0,		"lda",
+0,	ADDOP,		0x00,		"ora",
+0,	ADDOP,		0xE0,		"sbc",
+0,	ADDOP,		0x80,		"sta",
+0,	ROLOP,		0x00,		"asl",
+0,	ROLOP,		0x40,		"lsr",
+0,	ROLOP,		0x20,		"rol",
+0,	ROLOP,		0x60,		"ror",
+0,	BRAOP,		0x90,		"bcc",
+0,	BRAOP,		0xB0,		"bcs",
+0,	BRAOP,		0xF0,		"beq",
+0,	BRAOP,		0x30,		"bmi",
+0,	BRAOP,		0xD0,		"bne",
+0,	BRAOP,		0x10,		"bpl",
+0,	BRAOP,		0x50,		"bvc",
+0,	BRAOP,		0x70,		"bvs",
+0,	BITOP,		0x24,		"bit",
+0,	NOPOP,		0x00,		"brk",
+0,	NOPOP,		0x18,		"clc",
+0,	NOPOP,		0xD8,		"cld",
+0,	NOPOP,		0x58,		"cli",
+0,	NOPOP,		0xB8,		"clv",
+0,	NOPOP,		0xCA,		"dex",
+0,	NOPOP,		0x88,		"dey",
+0,	NOPOP,		0xE8,		"inx",
+0,	NOPOP,		0xC8,		"iny",
+0,	NOPOP,		0xEA,		"nop",
+0,	NOPOP,		0x48,		"pha",
+0,	NOPOP,		0x08,		"php",
+0,	NOPOP,		0x68,		"pla",
+0,	NOPOP,		0x28,		"plp",
+0,	NOPOP,		0x40,		"rti",
+0,	NOPOP,		0x60,		"rts",
+0,	NOPOP,		0x38,		"sec",
+0,	NOPOP,		0xF8,		"sed",
+0,	NOPOP,		0x78,		"sei",
+0,	NOPOP,		0xAA,		"tax",
+0,	NOPOP,		0xA8,		"tay",
+0,	NOPOP,		0x98,		"tya",
+0,	NOPOP,		0xBA,		"tsx",
+0,	NOPOP,		0x8A,		"txa",
+0,	NOPOP,		0x9A,		"txs",
+0,	CPXOP,		0xE0,		"cpx",
+0,	CPXOP,		0xC0,		"cpy",
+0,	INCOP,		0xC0,		"dec",
+0,	INCOP,		0xE0,		"inc",
+0,	JMPOP,		0x4C,		"jmp",
+0,	JSROP,		0x20,		"jsr",
+0,	LDXOP,		0xA0,		"ldx",
+0,	LDYOP,		0xA0,		"ldy",
+0,	STXOP,		0x80,		"stx",
+0,	STYOP,		0x80,		"sty",
+0,	PSEU,		0x1860,		"add",
+0,	PSEU,		0x38E0,		"sub",
diff --git a/mach/6500/as/mach4.c b/mach/6500/as/mach4.c
new file mode 100644
index 000000000..bbef65381
--- /dev/null
+++ b/mach/6500/as/mach4.c
@@ -0,0 +1,157 @@
+#define RCSID4 "$Header$"
+
+/*
+ * (c) copyright 1983 by the Vrije Universiteit, Amsterdam, The Netherlands.
+ *
+ *          This product is part of the Amsterdam Compiler Kit.
+ *
+ * Permission to use, sell, duplicate or disclose this software must be
+ * obtained in writing. Requests for such permissions may be sent to
+ *
+ *      Dr. Andrew S. Tanenbaum
+ *      Wiskundig Seminarium
+ *      Vrije Universiteit
+ *      Postbox 7161
+ *      1007 MC Amsterdam
+ *      The Netherlands
+ *
+ */
+
+/*
+ * Mostek 6500 parsing tables.
+ */
+
+expr
+	:	expr	EXTENSION
+			{ $$.val = ($1.val >> $2) & 0xFF;
+			  $$.typ = combine($1.typ, S_ABS, '&');
+			}
+	;
+operation
+	:	NOPOP
+			{ emit1($1); }
+	|	BITOP	expr
+			{ code($2,$1,$1+8); }
+	|	JMPOP	expr
+			{ emit1($1);
+#ifdef RELOCATION
+			  newrelo($2.typ, RELO2);
+#endif
+			  emit2($2.val);
+			}
+	|	JMPOP	'(' expr ')'
+			{ emit1($1+0x20);
+#ifdef RELOCATION
+			  newrelo($3.typ, RELO2);
+#endif
+			  emit2($3.val);
+			}
+	|	JSROP	expr
+			{ emit1($1);
+#ifdef RELOCATION
+			  newrelo($2.typ, RELO2);
+#endif
+			  emit2($2.val);
+			}
+	|	LDXOP	'#' expr
+			{ emit1(0xA2);
+#ifdef RELOCATION
+			  newrelo($3.typ, RELO1);
+#endif
+			  emit1($3);
+			}
+	|	LDXOP	expr
+			{ code($2,0xA6,0xAE); }
+	|	LDXOP	expr ',' Y
+			{ code($2,0xB6,0xBE); }
+	|	LDYOP	'#' expr
+			{ emit1(0xA0);
+#ifdef RELOCATION
+			  newrelo($3.typ, RELO1);
+#endif
+			  emit1($3);
+			}
+	|	LDYOP	expr
+			{ code($2,0xA4,0xAC); }
+	|	LDYOP	expr ',' X
+			{ code($2,0xB4,0xBC); }
+	|	STXOP	expr
+			{ code($2,$1+0x06,$1+0x0E); }
+	|	STXOP	expr ',' Y
+			{ emit1($1+0x16);
+#ifdef RELOCATION
+			  newrelo($2.typ, RELO1);
+#endif
+			  emit1(lowb($2.val));
+			}
+	|	STYOP	expr
+			{ code($2,$1+0x04,$1+0x0C); }
+	|	STYOP	expr ',' X
+			{ emit1($1+0x14);
+#ifdef RELOCATION
+			  newrelo($2.typ, RELO1);
+#endif
+			  emit1(lowb($2.val));
+			}
+	|	addop	'#' expr
+			{ if ($1==0x80) serror("no store immediate");
+			  emit1($1+0x09);
+#ifdef RELOCATION
+			  newrelo($3.typ, RELO1);
+#endif
+			  emit1($3);
+			}
+	|	addop	expr
+			{ code($2,$1+0x05,$1+0x0D); }
+	|	addop	expr ',' X
+			{ code($2,$1+0x15,$1+0x1D); }
+	|	addop	expr ',' Y
+			{ emit1($1+0x19);
+#ifdef RELOCATION
+			  newrelo($2.typ, RELO2);
+#endif
+			  emit2($2.val);
+			}
+	|	addop	'(' expr ',' X ')'
+			{ emit1($1+0x01);
+#ifdef RELOCATION
+			  newrelo($3.typ, RELO1);
+#endif
+			  emit1(lowb($3.val));
+			}
+	|	addop	'(' expr ')' ',' Y
+			{ emit1($1+0x11);
+#ifdef RELOCATION
+			  newrelo($3.typ, RELO1);
+#endif
+			  emit1(lowb($3.val));
+			}
+	|	ROLOP	/* Default is A. */
+			{ emit1($1+0x0A); }
+	|	ROLOP	A
+			{ emit1($1+0x0A); }
+	|	ROLOP	expr
+			{ code($2,$1+0x06,$1+0x0E); }
+	|	ROLOP	expr ',' X
+			{ code($2,$1+0x16,$1+0x1E); }
+	|	BRAOP	expr
+			{ branch($1,$2); }
+	|	CPXOP	'#' expr
+			{ emit1($1+0x00);
+#ifdef RELOCATION
+			  newrelo($3.typ, RELO1);
+#endif
+			  emit1($3);
+			}
+	|	CPXOP	expr
+			{ code($2,$1+0x04,$1+0x0C); }
+	|	INCOP	expr
+			{ code($2,$1+0x06,$1+0x0E); }
+	|	INCOP	expr ',' X
+			{ code($2,$1+0x16,$1+0x1E); }
+	;
+addop
+	:	ADDOP
+	|	PSEU
+			{ emit1($1>>8); $$ = $1 & 0xFF; }
+	;
diff --git a/mach/6500/as/mach5.c b/mach/6500/as/mach5.c
new file mode 100644
index 000000000..2f45af9e0
--- /dev/null
+++ b/mach/6500/as/mach5.c
@@ -0,0 +1,41 @@
+#define RCSID5 "$Header$"
+
+/*
+ * Mostek 6500 special routines.
+ */
+
+branch(opc, exp)
+register int	opc;
+expr_t		exp;
+{
+	register int	dist;
+
+	dist = exp.val - (DOTVAL + 2);
+	if (pass == PASS_2 && dist > 0 && !(exp.typ & S_DOT))
+		dist -= DOTGAIN;
+	if (small(fitb(dist) && (exp.typ & ~S_DOT) == DOTTYP, 3)) {
+		emit1(opc); emit1(dist);
+	} else {
+		emit1(opc^0x20); emit1(0x03);	/* Skip over ... */
+		emit1(0x4C);			/* ... far jump. */
+#ifdef RELOCATION
+		newrelo(exp.typ, RELO2);
+#endif
+		emit2(exp.val);
+	}
+}
+
+code(exp, opc1, opc2)
+expr_t		exp;
+register int	opc1, opc2;
+{
+	if (small((exp.typ & S_TYP) == S_ABS && fits_zeropage(exp.val), 1)) {
+		emit1(opc1); emit1(exp.val);
+	} else {
+		emit1(opc2);
+#ifdef RELOCATION
+		newrelo(exp.typ, RELO2);
+#endif
+		emit2(exp.val);
+	}
+}