Numbers, Bits and ASCII
Atom number forms
| Form | Meaning | Example |
|---|---|---|
42 | decimal | 42 |
$2A | hexadecimal | $2A |
%00101010 | binary | %00101010 |
02AH | Intel hexadecimal suffix | 02AH |
00101010B | Intel binary suffix | 00101010B |
Hex digit table
| Hex | Binary | Decimal |
|---|---|---|
0 | 0000 | 0 |
1 | 0001 | 1 |
2 | 0010 | 2 |
3 | 0011 | 3 |
4 | 0100 | 4 |
5 | 0101 | 5 |
6 | 0110 | 6 |
7 | 0111 | 7 |
8 | 1000 | 8 |
9 | 1001 | 9 |
A | 1010 | 10 |
B | 1011 | 11 |
C | 1100 | 12 |
D | 1101 | 13 |
E | 1110 | 14 |
F | 1111 | 15 |
Common hexadecimal landmarks
| Value | Decimal | Why it matters |
|---|---|---|
$00 | 0 | zero byte |
$0F | 15 | low nibble all set |
$10 | 16 | one hex digit boundary |
$1F | 31 | 5-bit max unsigned |
$20 | 32 | ASCII space |
$7F | 127 | 7-bit signed max / ASCII top |
$80 | 128 | sign bit set |
$FF | 255 | byte all set / -1 in two's complement |
$0100 | 256 | common code base |
$7FFF | 32767 | signed 16-bit positive max |
$8000 | 32768 | high bit set in a word / common RAM base |
$FFFF | 65535 | word all set / -1 as 16-bit two's complement |
7-bit ASCII (0–127)
| Dec | Hex | Character | Meaning |
|---|---|---|---|
| 0 | $00 | NUL | control code |
| 1 | $01 | SOH | control code |
| 2 | $02 | STX | control code |
| 3 | $03 | ETX | control code |
| 4 | $04 | EOT | control code |
| 5 | $05 | ENQ | control code |
| 6 | $06 | ACK | control code |
| 7 | $07 | BEL | control code |
| 8 | $08 | BS | control code |
| 9 | $09 | TAB | control code |
| 10 | $0A | LF | control code |
| 11 | $0B | VT | control code |
| 12 | $0C | FF | control code |
| 13 | $0D | CR | control code |
| 14 | $0E | SO | control code |
| 15 | $0F | SI | control code |
| 16 | $10 | DLE | control code |
| 17 | $11 | DC1 | control code |
| 18 | $12 | DC2 | control code |
| 19 | $13 | DC3 | control code |
| 20 | $14 | DC4 | control code |
| 21 | $15 | NAK | control code |
| 22 | $16 | SYN | control code |
| 23 | $17 | ETB | control code |
| 24 | $18 | CAN | control code |
| 25 | $19 | EM | control code |
| 26 | $1A | SUB | control code |
| 27 | $1B | ESC | control code |
| 28 | $1C | FS | control code |
| 29 | $1D | GS | control code |
| 30 | $1E | RS | control code |
| 31 | $1F | US | control code |
| 32 | $20 | space | printable |
| 33 | $21 | ! | printable |
| 34 | $22 | " | printable |
| 35 | $23 | # | printable |
| 36 | $24 | $ | printable |
| 37 | $25 | % | printable |
| 38 | $26 | & | printable |
| 39 | $27 | ' | printable |
| 40 | $28 | ( | printable |
| 41 | $29 | ) | printable |
| 42 | $2A | * | printable |
| 43 | $2B | + | printable |
| 44 | $2C | , | printable |
| 45 | $2D | - | printable |
| 46 | $2E | . | printable |
| 47 | $2F | / | printable |
| 48 | $30 | 0 | printable |
| 49 | $31 | 1 | printable |
| 50 | $32 | 2 | printable |
| 51 | $33 | 3 | printable |
| 52 | $34 | 4 | printable |
| 53 | $35 | 5 | printable |
| 54 | $36 | 6 | printable |
| 55 | $37 | 7 | printable |
| 56 | $38 | 8 | printable |
| 57 | $39 | 9 | printable |
| 58 | $3A | : | printable |
| 59 | $3B | ; | printable |
| 60 | $3C | < | printable |
| 61 | $3D | = | printable |
| 62 | $3E | > | printable |
| 63 | $3F | ? | printable |
| 64 | $40 | @ | printable |
| 65 | $41 | A | printable |
| 66 | $42 | B | printable |
| 67 | $43 | C | printable |
| 68 | $44 | D | printable |
| 69 | $45 | E | printable |
| 70 | $46 | F | printable |
| 71 | $47 | G | printable |
| 72 | $48 | H | printable |
| 73 | $49 | I | printable |
| 74 | $4A | J | printable |
| 75 | $4B | K | printable |
| 76 | $4C | L | printable |
| 77 | $4D | M | printable |
| 78 | $4E | N | printable |
| 79 | $4F | O | printable |
| 80 | $50 | P | printable |
| 81 | $51 | Q | printable |
| 82 | $52 | R | printable |
| 83 | $53 | S | printable |
| 84 | $54 | T | printable |
| 85 | $55 | U | printable |
| 86 | $56 | V | printable |
| 87 | $57 | W | printable |
| 88 | $58 | X | printable |
| 89 | $59 | Y | printable |
| 90 | $5A | Z | printable |
| 91 | $5B | [ | printable |
| 92 | $5C | \\ | printable |
| 93 | $5D | ] | printable |
| 94 | $5E | ^ | printable |
| 95 | $5F | _ | printable |
| 96 | $60 | ` | printable |
| 97 | $61 | a | printable |
| 98 | $62 | b | printable |
| 99 | $63 | c | printable |
| 100 | $64 | d | printable |
| 101 | $65 | e | printable |
| 102 | $66 | f | printable |
| 103 | $67 | g | printable |
| 104 | $68 | h | printable |
| 105 | $69 | i | printable |
| 106 | $6A | j | printable |
| 107 | $6B | k | printable |
| 108 | $6C | l | printable |
| 109 | $6D | m | printable |
| 110 | $6E | n | printable |
| 111 | $6F | o | printable |
| 112 | $70 | p | printable |
| 113 | $71 | q | printable |
| 114 | $72 | r | printable |
| 115 | $73 | s | printable |
| 116 | $74 | t | printable |
| 117 | $75 | u | printable |
| 118 | $76 | v | printable |
| 119 | $77 | w | printable |
| 120 | $78 | x | printable |
| 121 | $79 | y | printable |
| 122 | $7A | z | printable |
| 123 | $7B | { | printable |
| 124 | $7C | | | printable |
| 125 | $7D | } | printable |
| 126 | $7E | ~ | printable |
| 127 | $7F | DEL | control code |