RCA COSMAC Operator's Manual page 105

'REGISTER OPERATIONS
-77-
PPFUmIX A- INSTRUCTICl' l SlM' \ t\RY
CONTROL
70 RET RETURN M(R X ,)+xp R(X)+1 1+IE
71 DIS ~LE M(R X ')~XP RCX)+l.O+IE
1/'d I:>AV
iiIiiiii . .
T . . -+M.R.X.)I) . . . .
~
I!m
IfNCRFMFNT R N +1
DEC DECREMENTR~N' -1
aN GL
IGE
L
R N
-+0
9N GHI GET HI
R:N
-+0
IAN
IPL P +1iN
IBN
IPHI PUT HI
[}+R
N .1
MEMORY REFERENCE
roo
IDLIIDLE
ON SEPISET P
')(
WAIT FOR INTERRUPT/DMAIN/DMAOUT
ALU OPERATIONS
~
;r:w
''',In
BY X
M R X
->0
1 OR OR
M R X
[}+
F2 lAND lAND M R X '[}+D
F3 XOR EXCL.OR
M R X )(jl{)+D
F lArD ADD
M R X +0-+0 •C-+OF
lit
F SD SUBrRACT
R x -[)+DC-+OF
lit
F SHR SHIFT RT
SHIFT D RT LSB-+OF
lit F
M SUBTRACT M
D-M R xn+D C-+OF
F LDI LOAD II1'1ED.
M R P
-+0
R P )+1
F ORI OR IM'1ED.
M R P 1/0-+0 R P +1
FA ANI AND IMMED.
M R P .[)+p R P)+1
FB XRI EXCL OR 111' 1 M R P
Q)[}+D
R P +1
lit
FC lAD I ADD IMM
1M R
,
.... +0-+0
C~DF
R P +.1
FD SDI SUBT D 111' 1
M R P -0-+0 C-+OF R P +1
Ft- ISMI I~Utl
Mll1'1
D-M R P))-+O C-+OF R P +1
INPUT-OUTPUT BYTE TRANSFER
60 OUT 0 OUTPUT 0
M R X
~1Jc:. p''){'
.N=O
Dl
OUTPUT 1 M R X
-+-Ell
S. R
'X
.N=1
2 OUT 2 OUTPUT 2
M R X +BUS R X +1 N=2
nl
nI
TPUT
~
M R X
~ -:~
1+ DUT
IOUTPU 4
M
'R .'){'
l+$l 1+
=4
is
OUT
OUTPUT 5 M R X
~
1+
~~
lb
UT IOUTP IT
M R X
~
1+ ="
17 OUT OUTP
101
=7
IN
NPI
RI 1/<;·oM
'li =
N INPU 1 BUS-+M R X
N=
TN
INPUT 2
BUS-+M R X N-A
B
IN INPUT ~
BUS*' R X N=tl
C IN INPUT
4 BUS~
R X
N::(;
D IN INPUT
5
B
-
E IN
I
INPUT
I;
BUS-+M R X
N-E
F IN INPUT 7
BUS-+M R X NO-F
COSMAC REGISTER SUI-t1ARY
HEX IDEC IMAL CODE
D
a BITS DATA REGISTER '"
, .... "
l\Tf'lI)~
DF 1 BIT
DATA FLAG (ALU ~ARRY)
R 116 BITS 1 OF 16 SCRATCHPAD REGISTERS
P
1+
BITS
DES I
f..NA
TFS WH
~H
R IS PR IGM CTR
IX
'+
BITS
DESIGNATES R(X)
N 4 BITS
LOtI RDFR INSTRUCTION DIGIT
I
'+
BITS
HTI:H
()RI')FI:1
"\'<;,1:111rT CN DIGIT
T a BITS
HOLDS OL D XP AFTER INTERRUPT
IE 1 BIT INTERRUPT ENABLE
,
BRANCHING
30 BR LNCOND.BR.
M R P
~R
P .0
32 BZ BR. IF D-OO M R P
~
P .0 IF D-=OO/RCP)+l
BDF BR IF DF
1101'1) ~R
P IF DF=l/R( P)+1
Bl
BR. IF EF1=1 M R(P )+R(p).o IF EFl=I/R P +1
3 B2 BR. IF
EF=~= M R :p .....RCP . IF EF?= rR P +
3 B3 BR. IF EF3=1
M R P ~CP).O IF EF>=lIR 'p' +1
'.R..
BR. IF EF4=1 M R P +R(P).O IF EF4=1/R(P +1
I
SKIP
R'P
+
BR. IF DxOO M R P
,~
'P'
IF
+'
BR. IF NO DF
WI)
P +R P .0 IF DF=O !(P)+1
C BNl BR. IF EFl-
101'1)
P'
I~
P .0 IF EFl= R P +1
IBR. IF EF2=0 M R P +R P .0 IF EF2=
R P +
BR IF EForO- M R P +R P .0 IF EF3
R P +1
F BN4 BR. IF EF4=0 M R P +R P .0 IF EF4=
R P +1
lit
THESE ARE THE ONLY OPERATIONS THAT MODIFY DF.
DF IS SET TO OR BY AN ALU CARRY DURING ADD OR SUBT.
HEX BINARY
0
0000
nor
2 0010
3
1
1+
IOU
5 lCl
b
10
7 11
INTERRUPT
SET TO 1;
rl\ITI=DDIIDT
HEX BINARY
a 1000
9 1001
-A
Ito
B
1 III
C
1 Oil
D 1
)1
E
1110
F
1111
ACTION:
X,P~T;
P
X POINTER SET TO
1="'f.RII= C:I=T TO , .
POINTER
2 •
,