6809 REGISTER SET
The following is a list of the 6809 registers used by AS6809:
a,b - 8-bit accumulators
d - 16-bit accumulator <a:b>
x,y - index registers
s,u - stack pointers
pc - program counter
cc - condition code
dp - direct page
6809 INSTRUCTION SET
The following tables list all 6809 mnemonics recognized by
the AS6809 assembler. The designation [] refers to a required
addressing mode argument. The following list specifies the
format for each addressing mode supported by AS6809:
#data immediate data
byte or word data
*dir direct page addressing
(see .setdp directive)
0 <= dir <= 255
label branch label
r,r1,r2 registers
cc,a,b,d,dp,x,y,s,u,pc
,-x ,--x register indexed
autodecrement
,x+ ,x++ register indexed
autoincrement
,x register indexed addressing
zero offset
offset,x register indexed addressing
-16 <= offset <= 15 --- 5-bit
-128 <= offset <= -17 --- 8-bit
16 <= offset <= 127 --- 8-bit
-32768 <= offset <= -129 --- 16-bit
128 <= offset <= 32767 --- 16-bit
(external definition of offset
uses 16-bit mode)
a,x accumulator offset indexed addressing
ext extended addressing
ext,pc pc addressing ( pc <- pc + ext )
ext,pcr pc relative addressing
[,--x] register indexed indirect
autodecrement
[,x++] register indexed indirect
autoincrement
[,x] register indexed indirect addressing
zero offset
[offset,x] register indexed indirect addressing
-128 <= offset <= 127 --- 8-bit
-32768 <= offset <= -129 --- 16-bit
128 <= offset <= 32767 --- 16-bit
(external definition of offset
uses 16-bit mode)
[a,x] accumulator offset indexed
indirect addressing
[ext] extended indirect addressing
[ext,pc] pc indirect addressing
( [pc <- pc + ext] )
[ext,pcr] pc relative indirect addressing
The terms data, dir, label, offset, and ext may all be expres-
sions.
Note that not all addressing modes are valid with every in-
struction, refer to the 6809 technical data for valid modes.
Inherent Instructions
abx daa
mul nop
rti rts
sex swi
swi1 swi2
swi3 sync
Short Branch Instructions
bcc label bcs label
beq label bge label
bgt label bhi label
bhis label bhs label
ble label blo label
blos label bls label
blt label bmi label
bne label bpl label
bra label brn label
bvc label bvs label
bsr label
Long Branch Instructions
lbcc label lbcs label
lbeq label lbge label
lbgt label lbhi label
lbhis label lbhs label
lble label lblo label
lblos label lbls label
lblt label lbmi label
lbne label lbpl label
lbra label lbrn label
lbvc label lbvs label
lbsr label
Single Operand Instructions
asla aslb
asl []
asra asrb
asr []
clra clrb
clr []
coma comb
com []
deca decb
dec []
inca incb
inc []
lsla lslb
lsl []
lsra lsrb
lsr []
nega negb
neg []
rola rolb
rol []
rora rorb
ror []
tsta tstb
tst []
Double Operand Instructions
adca [] adcb []
adda [] addb []
anda [] andb []
bita [] bitb []
cmpa [] cmpb []
eora [] eorb []
lda [] ldb []
ora [] orb []
sbca [] sbcb []
sta [] stb []
suba [] subb []
D-register Instructions
addd [] subd []
cmpd [] ldd []
std []
Index/Stack Register Instructions
cmps [] cmpu []
cmpx [] cmpy []
lds [] ldu []
ldx [] ldy []
leas [] leau []
leax [] leay []
sts [] stu []
stx [] sty []
pshs r pshu r
puls r pulu r
Jump and Jump to Subroutine Instructions
jmp [] jsr []
Register - Register Instructions
exg r1,r2 tfr r1,r2
Condition Code Register Instructions
andcc #data orcc #data
cwai #data
6800 Compatibility Instructions
aba cba
clc cli
clv des
dex ins
inx
ldaa [] ldab []
oraa [] orab []
psha pshb
pula pulb
sba sec
sei sev
staa [] stab []
tab tap
tba tpa
tsx txs
wai
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Last Updated: September 2023