68HC16 REGISTER SET
The following is a list of the 68HC16 registers used by AS6816:
a,b - 8-bit accumulators
d - 16-bit accumulator <a:b>
e - 16-bit accumulator
x,y,z - index registers
k - address extension register
s - stack pointer
ccr - condition code
68HC16 INSTRUCTION SET
The following tables list all 68HC16 mnemonics recognized by
the AS6816 assembler. The designation [] refers to a required
addressing mode argument. The following list specifies the
format for each addressing mode supported by AS6816:
#data immediate data
byte or word data
#xo,#yo local immediate data (mac / rmac)
label branch label
r register
ccr,a,b,d,e,x,y,z,s
,x zero offset register indexed addressing
,x8
,x16
offset,x register indexed addressing
0 <= offset <= 255 --- 8-bit
-32768 <= offset <= -1 --- 16-bit
256 <= offset <= 32767 --- 16-bit
(external definition of offset
uses 16-bit mode)
offset,x8 unsigned 8-bit offset indexed addressing
offset,x16 signed 16-bit offset indexed addressing
e,x accumulator offset indexed addressing
ext extended addressing
bank 64K bank number (jmp / jsr)
The terms data, label, offset, bank, and ext may all be expres-
sions.
Note that not all addressing modes are valid with every in-
struction, refer to the 6816 technical data for valid modes.
Instruction Notes
Several instructions have argument conditions that can be
confusing to the uninitiated. The AIS, AIX, AIY, AIZ, ADDD, and
ADDE instructions have 8 and 16 bit immediate forms:
AIS ii and
AIS jjkk
Where each argument is sign extended to 20 bits. This means
that the 8 bit value is between -128 and +127 and the 16 bit
value is between -32768 and +32765. The assembler checks for a
constant argument with a value from -128 to +127 and emits the
8 bit opcode and signed 8 bit value. This implies that that an
argument 0xFC, often used to specify a value of -4 when dealing
with 8 bit arguments, is not -4 but +252. The assembler will
emit the 16 bit opcode and the value 0x00FC, not what was ex-
pected.
Inherent Instructions
aba abx aby abz
ace aced ade adx
ady adz aex aey
aez bgnd cba daa
ediv edivs emul emuls
fdiv fmuls idiv ldhi
lpstop mul nop psha
pshb pshmac pula pulb
pulmac rtr rts sba
sde sted swi sxt
tab tap tba tbek
tbsk tbxk tbyk tbzk
tde tdmsk tdp ted
tedm tekb tem tmer
tmet tmxed tpa tpd
tskb tsx tsy tsz
txkb txs txy txz
tykb tys tyx tyz
tzkb tzs tzx tzy
wai xgab xgde xgdx
xgdy xgdz xgex xgey
xgez
Push/Pull Multiple Register Instructions
pshm r,... pulm r,...
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
Bit Manipulation Instructions
bclr [],#data
bset [],#data
brclr [],#data,label
brset [],#data,label
Single Operand Instructions
asla aslb
asld asle
aslm
asl [] aslw []
asra asrb
asrd asre
asrm
asr [] asrw []
clra clrb
clrd clre
clrm
clr [] clrw []
coma comb
comd come
com [] comw []
deca decb
dec [] decw []
inca incb
inc [] incw []
lsla lslb
lsld lsle
lslm
lsl [] lslw []
lsra lsrb
lsrd lsre
lsr [] lsrw []
nega negb
negd nege
neg [] negw []
rola rolb
rold role
rol [] rolw []
rora rorb
rord rore
ror [] rorw []
tsta tstb
tsta tste
tst [] tstw []
Double Operand Instructions
adca [] adcb []
adcd [] adce []
adda [] addb []
addd [] adde []
anda [] andb []
andd [] ande []
bita [] bitb []
cmpa [] cmpb []
cpd [] cpe []
eora [] eorb []
eord [] eore []
ldaa [] ldab []
ldd [] lde []
oraa [] orab []
ord [] ore []
sbca [] sbcb []
sbcd [] sbce []
staa [] stab []
std [] ste []
suba [] subb []
subd [] sube []
Index/Stack Register Instructions
cps [] cpx []
cpy [] cpz []
lds [] ldx []
ldy [] ldz []
sts [] stx []
sty [] stz []
Jump and Jump to Subroutine Instructions
jmp bank,[] jsr bank,[]
Condition Code Register Instructions
andp #data orp #data
Multiply and Accumulate Instructions
mac #data rmac #data
mac #xo,#yo rmac #xo,#yo
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