1 .\" $Id: 6800_as.6,v 1.3 1994/06/24 14:01:36 ceriel Exp $
2 .TH 6800_AS 6 "$Revision: 1.3 $"
5 6800_as \- assembler for Motorola 6800
7 ~em/lib.bin/6800/as [options] argument ...
9 This assembler is made with the general framework
10 described in \fIuni_ass\fP(6). It is an assembler generating relocatable
11 object code in \fIAck.out\fP(5) format.
14 The 6800 has two accumulator registers, A and B. An instruction that refers
15 to accumulator A, has an "a" as last character. In the same way a "b" means
16 that the instruction uses B as accumulator.
17 .IP "addressing modes"
19 .ta 8n 16n 24n 32n 40n 48n
22 #expr with cpx, ldx, lds a 2-byte value,
23 otherwise a 1-byte value (immediate)
25 <expr 1-byte address. Not allowed with:
26 asl, asr, clr, com, dec, inc, lsl, lsr,
27 neg, rol, ror, tst (base page direct)
29 expr 2-byte address (extended direct)
31 expr, x 1-byte expr + contents of x
32 yields address (indexed)
39 A. Osborne, 6800 programming for logic design,
40 Adam Osborne and Associates Inc., 1977
42 An example of Motorola 6800 assembly code.
45 .ta 8n 16n 32n 40n 48n 56n 64n
46 .sect .text; .sect .data
51 bhs someplace ! branch on carry clear
53 adda #18 ! add 18 to accumulator A