Jamaica 10 ch11 Illegal Op-codes
From C64 Diskmag Wiki
illegal op-codes tjost
----------------------------------------
we are now going to reveal the deepest
secrets of 6510 coding. this is not a
chapter for beginners, but i hope that
someone can find a use for it.
if you find this chapter interesting,
but not satisfying then you should
contact me (my addy should be in the
addy chapters) for more information
about illegal op-codes or just any
code-related talk.
and now lets roll.....
code addressing name b c
--------------------------
02 implied hlt 1 -
03 (zeropage,x) slo 2 8
04 zeropage nop 2 3
07 zeropage slo 2 5
0b #immediate ana 2 2
0c absolute nop 3 4
0f absolute slo 3 6
12 implied hlt 1 -
13 (zeropage),y slo 2 8
14 zeropage,x nop 2 4
17 zeropage,x slo 2 6
1a implied nop 1 2
1b absolute,y slo 3 7
1c absolute,x nop 3 4*
1f absolute,x slo 3 7
22 implied hlt 1 -
23 (zeropage,x) rla 2 8
27 zeropage rla 2 5
2b #immediate anb 2 2
2f absolute rla 3 6
32 implied hlt 1 -
33 (zeropage),y rla 2 8
34 zeropage,x nop 2 4
37 zeropage,x rla 2 6
3a implied nop 1 2
3b absolute,y rla 3 7
3c absolute,x nop 3 4*
3f absolute,x rla 3 7
42 implied hlt 1 -
43 (zeropage,x) sre 2 8
44 zeropage nop 2 3
47 zeropage sre 2 5
4b #immediate ram 2 2
4f absolute sre 3 6
52 implied hlt 1 -
53 (zeropage),y sre 2 8
54 zeropage,x nop 2 4
57 zeropage,x sre 2 6
5a implied nop 1 2
5b absolute,y sre 3 6
5c absolute,x nop 3 4*
5f absoulte,x sre 3 7
62 implied hlt 1 -
63 (zeropage,x) rra 2 8
64 zeropage nop 2 3
67 zeropage rra 2 5
6b #immediate rbm 2 2
6f absoulte rra 3 6
72 implied hlt 1 -
73 (zeropage),y rra 2 8
74 zeropage,x nop 2 4
77 zeropage,x rra 2 6
7a implied nop 1 2
7b absolute,y rra 3 7
7c absolute,x nop 3 4*
7f absolute,x rra 3 7
80 #immediate nop 2 2
82 #immediate nop 2 2
83 (zeropage,x) aax 2 6
87 zeropage aax 2 3
89 #immediate nop 2 2
8b #immediate axm 2 2
8f absolute aax 3 4
92 implied hlt 1 -
93 (zeropage),y tea 2 6
97 zeropage,y aax 2 4
9b absolute,y axs 3 5
9c absolute,x tey 3 5
9e absolute,y tex 3 5
9f absolute,y tea 3 5
a3 (zeropage,x) lax 2 6
a7 zeropage lax 2 3
ab #immediate lax 2 2
af absolute lax 3 4
b2 implied hlt 1 -
b3 (zeropage),y lax 2 5*
b7 zeropage,y lax 2 4
bb absolute,y las 3 4*
bf absolute,y lax 3 4*
c2 #immediate nop 2 2
c3 (zeropage,x) dcp 2 8
c7 zeropage dcp 2 5
cb #immediate xma 2 2
cf absolute dcp 3 6
d2 implied hlt 1 -
d3 (zeropage),y dcp 2 8
d4 zeropage,x nop 2 4
d7 zeropage,x dcp 2 6
da implied nop 1 2
db absolute,y dcp 3 7
dc absolute,x nop 3 4*
df absolute,x dcp 3 7
e2 #immediate nop 2 2
e3 (zeropage,x) isb 2 8
e7 zeropage isb 2 5
eb #immediate sbc 2 2
ef absolute isb 3 6
f2 implied hlt 1 -
f3 (zeropage),y isb 2 8
f4 zeropage,x nop 2 4
f7 zeropage,x isb 2 6
fa implied nop 1 2
fb absolute,y isb 3 7
fc absolute,x nop 3 4*
ff absolute,x isb 3 7
and here's the description of what the
instruction does.
name flags description
------------------------
aax m = a and x
ana nzc asl #(a and m), and m
anb nzc rol #(a and m), and m
axm nz a = (x and m) and (a or #$ee)
axs m = a and x and #>m+$100
dcp nzc dec m, cmp m
hlt - total halt
isb nvzc inc m, sbc m
las nz lda (sp and m), tax, txs
lax nz lda m, tax
ram nzc and m, lsr a
rbm nzc and n, ror a
rla nzc rol m, and m
rra nvzc ror m, adc m
slo nzc asl m, ora m
sre nzc lsr m, eor m
tea m = a and x and #>m+$100
tex m = x and #>m+$100
tey m = y and #>m+$100
xma nzc x = (a and x) - m
notes:
a = accumulator x = x-register
y = y-register sp = stackpointer
m = byte in memory
addressing is the addressing mode for
that op-code.
name is the instructions mnemonic name.
b is the amount of bytes that the
instruction occupies in memory.
c is the amount of cycles the
instruction will take to execute where
* means add one cycle if page boundary
crossed.
flags is what flags the instruction
will affect while executing.
description briefly shows what each
instruction does.
well, that's it for this short
introduction into the hidden worlds of
the 6510....
signed : TJOST / JAM
