Index

A 
above MEMTOP 184
absolute 92
absolute addressing 92, 95
absolute indexed,
   X 92
   X addressing 92
   Y 92
   Y addressing 92
accumulator 45, 92
Accumulator addressing 92, 95
ADC 45, 65
ADC, example of usage 65
ADDNRS source program 92
add with carry 45, 65
addition operations 44
addition routine 45
address bus 44
address locations 29
addressing modes 91
allocating memory 185
alphabetical symbols 18
ALU 27, 43-45
AND operator 157
ANTIC MODE 214
ANTIC chip 212
Apple II, II+, //e, /// 15
Arithmetic Logic Unit 27, 43-44
arithmetic shift left 142
ASL 142
ASM 77
assembled programs 19
assemblers 18
assembling 66
assembling your program 76
assembly language instruction 19
assembly language loops 117
assembly language programmers 27
Atari BASIC 51
Atari XL computers 15
Atari hardware Read/Write registers 185
Atari rainbow program 151
ATASCII 107, 112, 188, 223
ATASCII characters 99
ATASCII codes 121
ATASCII-ASCII conversion subroutines 225

B
B 47,52
base, numbers 34
BASIC 13,18,19,32
BASIC, Atari 51
BASIC program 33
BCD 51, 162
BCD arithmetic 51
BCD numbers 51
binary coded decimal 51, 162
binary math, examples of 23-25
binary mode operation
binary multiplication 168
binary number chart 31
binary numbers 20,23,30
binary operations, multiple precision 161
binary style machine language 20
binary system 23
binary to hexadecimal 36
binary to hexadecimal conversion 36
binary to decimal 36
bit 0 49
bit 1 50
bit 2 50
bit 3 51
bit 4 52
bit 5 52
bit 6 52
bit 7 52
BIT operator 160
bits 26
bonus program 53
borrowing and carrying 49
break flag 47, 52
break instruction in debugging 52
BRK 52
BSAVE 51, 71
bus, address 44
bus, data 44, 45
buses 44
.BYTE directive 111-112
byte, least signifcant 32
byte, most signifcant 32
bytes 26

C
C 47,  49
calculating and indexed or relative address 98
carriage return 100
carry bit 142
carry bit set 153
carry flag (C) 47
carry flag 47, 49
carrying and borrowing 49
cartridge slot A 184
cartridge slot B 184
cassette data recorder 14
central processing unit 14, 43
central I/O utility 196
changing the value of the MEMLOpointer program 192
character set, foreign language 15
chart for writing conditional branching instructions 116
CIO 196
CIO vector 199
CIOV 199
circuit 14
CLC 50
CLD 51
clear carry 50
clear carry bit 153
clear flag 49
clear interrupt 51
clear the decimal flag 51
clearing a text buffer 122
clearing the stack 135
CLI 51
closing a device 209
CLV 52
coarse scrolling 227-228
COBOL 18, 19
color clocks 240
color register 147
command error 80
command 
  BSAVE 83
  ENTER 83
  Graphics 0 13
  LIST 83
  LOAD 83
  SAVE 83
comments 61, 62
Commodore 64 computer 15
Commodore PET computer 15
comparing values 44
comparison instructions 97, 113
compiler 18
complement 176
computer languages 18
computer programs 17
computer, 16 bit 28, 29
condition flags 47
conditional branching 96
conditional branching instructions 96-97
conditional branching instructions, writing 116
conserving memory 22
contents 94
conversion chart 35
conversion remainders 35
conversion routine 223
converting ATASCII to screen code 223
converting binary to hexadecimal numbers 37
converting decimal numbers to binary numbers 37-38
CP/M 15
CPU 14, 43
CTIA chip 214
customized screen display program 220

D
D 47
D command 78, 80
data bus 44, 45
data bytes 196
data, packing 144
data, unpacking 145
debug mode 81
debugging utility 75-76
dec-hex conversion program 38-39
decimal mode flag 47, 49
decimal number chart 31
decimal numbers 30
decimal programs, ordinary 33
decimal to hexadecimal conversion 38
decimal to binary 35
decimal to binary conversion chart 35
decoding ATASCII 107
digital computer 23
directive, BYTE 111-112
directive, example of usage 66
directives 61
disk drive 14
display list 212
division operations 44
dollar signs 32
dollar signs in hexadecimal numbers 32
dot matrix characters 213

E
encoding ATASCII 107
END 84
ENTER command 83
entering your program 67
EOR 159
EOR truth table 159
examining RAM 5-4 78
example of coarse scrolling 228
executing a machine language program 75

F
files 196
fine scrolling 235-240
flag for test purposes only 53
flag, break 52
flag, carry 49
flag, negative 53
flag, overflow 52
flags 47
flags, condition 47
floating point 161
floating point ROM 185
floating point math 181
foreign language character set 15
FP 161
free RAM 183

G
G command 75, 81
GOSUB 21
Graphics 0 command 13
Graphics 0 214
Graphics 1 214
Graphics 2 214
graphic tablet 14
graphics chip 214
graphics modes 215
GTIA chip 212, 214

H
hardware Read/Write registers 185
hex code 204
hex dec conversion program 38-40
hexadecimal number chart 31
hexadecimal number system 30
hexadecimal numbers 30, 46
high level languages 18
horizontal scan lines 212
hortizontal scroll register 241
hortizontal scrolling 232

I
I 47
IBM PC 15, 28, 29
immediate 91
immediate addressing 91, 93
implicit(or implied) addressing 91, 93
indexed address 98
indexed addressing 99
indexed indirect 92
indexed indirect addressing 92, 101
indirect addressing 92, 100
indirect indexed 92
indirect indexed addressing 92
INIT 87
INIT address 83
input 43
input/output control blocks 197
input/output devices 14
instructions 20
instructions, comparison 113
interface 14
interpretation as memory address 46
interpreters 18
interrupt disable flag 47, 50
interrupts 50
I/O 14
I/O devices 195
I/O operations 196, 204
I/O system 200
I/O tokens 204
IOCB 197
IOCB address and bytes 205
IOCB error 209
IOCB offsets 203


J
JSR 21, 22
jump to subroutine 21

K
keeping track of pluses and minuses 52
keyboard 14

L
label length 61
labels 61
languages 17
last in, first out 104
L command 80
LDA 45
least significant bit 34
least significant byte 32
left-most bit 34
LIFO 104
line number ranges 58
line numbers 58
LIST 71, 83
literal numbers 46
LMS 217
LOAD 83
load memory scan 217
load the accumulator 45
logical shift right 142, 145
LOGO 18
LOMEM pointer 186
loops, assembly language 117
LSB 34
LSR 142, 145

M
machine language 18, 20
machine language instructions 19, 20
machine language program 22, 75
macro assembler 18
maskable interrupts 50
masking instructions 50-51
matrix system 29
maximum memory capacity 29
megabyte 29
MEMLO 183
MEMLO pointer 187-188
MEMLO to MEMTOP 183
memory 14, 16
memory address 16, 44, 46
memory addresses 183
memory location 16, 20, 28
memory locations 13, 28, 180, 181
memory map 28, 180, 181
memory map for page zero 181
memory register, 8 bit 27
memory, screen 184
MEMTOP 183
MEMTOP, above 184
microprocessor unit 14, 15
microprocessor, 6502 14, 15
mnemonics 61
mnemonics requiring operands 61
mode lines 214
modes of 6502 processor 92
MOS Technology 14
most significant byte 32
moving and modifying a character set 248
MPU 14, 43
MSB 34
multiple digit hex number to binary 36
multiple precision addition program 165
multiple precision binary operations 161
multiple precision multiplication program 169
multiplication operations 44

N
N 47
negative flag 47, 53
nibble 26
nonmaskable interrupts 51
notation system 18, 24
number base 34
number comparisons 50
number systems 34
numbers, literal 46
nybble 26, 32

O
object code 19, 21
Ohio Scientific computers 15
one's complement 176
op code 58, 61
op code column 111
OPEN command 199
OPEN statement 198
opening devices 197
operands 61
operating system 15
operating system ROM 185
operation code 61
optional parameters 84
Optimized System Software, Inc. 57
ordinary decimal programs 33
origin line 52
origin line, example of 52
OS 15
OSS 57
output 43
overflow flag 47, 52, 177
overflow flag (V) 47
overscan 213

P
packing data 144
page 6 179
page zero 94, 180
Pascal 18, 19
PC 47
PCH 47
PCL 47
PEEK 78
Penguin Math 23, 24, 30
PET computer 15
PHP 164
Pilot 18
player missile graphics 251
player missiles graphics program 256
pointer, LOMEM 186
pointer, MEMLO 187-189
pointer, changing LOMEM 188
POKE command 13
pound sign 45
P register 49-50
P register bits 47
P register's carry flag 50
processor status register 46, 47
processor status register, flags 47
processor status register, illustration 49
program counter 46, 82
program counter high 47
program counter low 47
program pointer 47
program  
  8 bit addition program 57
  ADDNRS source 92
  ATASCII ASCII conversion 225
  bonus no. 3 53
  changing the value of the MEMLO pointer 192
  coarse scrolling 230
  converting binary to hexadecimal numbers 37
  converting decimal numbers to binary numbers 37
  customized screen display 220
  dec-hex and hex-dec conversion program 38-40
  moving and modifying a character set 248
  multiple precision multiplication 169
  player missile graphics 256
  Response 125
  simple division 173
  the Atari rainbow 151
  The Visitor 110, 124
programmer 19
programmers 17
programming languages 17, 18
programs 17, 18
programs, assembly language 18
programs, computer 17
programs, machine language 22
pseudo op 111
pseudo operation code 111
pseudo ops 61

R
Radio Shack 15
Random Access Memory 14-16, 27
RAM 14-16, 27
RAM, examining 78
RAM, free 183
raster scan 212
Read Only Memory 14-16, 27
Read/Write registers 185
records 196
registers 46
relative 92
relative addressing 92, 96
remainders 35
rename file 85
Response program 125
RETURN 21
right-most bit 34, 49
ROL 142
ROM 14-16, 27
ROM, floating point 185
ROM, operating system 185
ROR 142
rotate left 142
rotate operations 50
rotate right 142
RTS 21, 22, 65
RTS instruction 79
RTS, example of usage 65
RUN address 82

S
S 47
SAVE 71
SAVE command 83
saving a machine language program 83
saving object code 71
saving your program 71
scan line 212, 214, 240
screen memory 184
scroll register, horizontal 241
scrolling registers 241
scrolling, fine 235-241
scrolling, hortizontal 232
scrolling, vertical 228
SDLSTH 220
SDLSTL 220
SDMCTL 220
SEC 50, 51
SED 51
SEI 51
self-diagnostic system 15
semicolons 61
set carry 50
set carry bit 153
set the decimal flag 51
set the interrupt flag 51
setting zero flag 50
shadow, direct memory access control 220
shadow, display list pointer-high 220
shadow, lisplay list pointer-low 220
shift operations 50
simple division program 173
SIZE command 189
sorting 16-bit numbers 32
source code 19
source code 21
SP 47
spacing directives 67
spacing for labels 61 
spacing in assembly language programs 58
special instruction list 212
STA 45, 46, 65
STA, example of usage 65
stack operations 135
stack pointer 46, 47
START 84
status flags 47
store the contents of the accumlator 45, 46
subtraction operations 44

T
telephone modem 14
text buffer, clearing 122
Text Editor package 18
The Atari rainbow 40
token 204
transmission lines 43
turning your keyboard into musical keyboard 53
two's complement 176
two state logic 23

U
unpacking data 145
unused bit 52
user addressable memory 16
USR function 133

V
V 52
vertical blank 213
vertical scrolling 211
video modem 14
video monitor 14
Visitor Program, The 110, 124
volatile 14

W
word 26
writing assembly language programs 58
writing conditional branching instructions 116

X
X register 44
X register, decrementing the 113
X register, incrementing the 114

Y
Y register 44
Y register, incrementing and decrementing 113

Z
Z 47, 50
Z 80 chip 15
zero flag 47, 50
zero flag, clear 50
zero page 91
zero page addressing 91, 94
zero page, X 92
zero page, X addressing 92, 100
zero page, Y 92
zero page, Y addressing 92, 100