6809 Post Bytes
Date: 2025-01-11 03:50:36 / Updated: 2025-01-11 03:50:36
Post bytes appear after a mnemonic, and describes the operand/address field.
Resources
- Table pulled directly from tim lindner's 6309 Indexed Addressing Mode Post Byte adendum to The 6309 Book.
- See page 29 for assembly language fields, and page 562 for post byte table, in 6809 Assembly Language Programming by Lance Leventhal (online).
6809 & 6309 Post Bytes Reference
6809 & 6309 Post Bytes Table
hex= post byte#= The number of bytes after the post byte~= Cycles for 6809/6309
| hex | binary | mnemonic | # | ~ | | hex | binary | mnemonic | # | ~ |
| --- | -------- | --------- |:---:| ----- | | --- | -------- | --------- |:---:| ----- |
| 00 | 00000000 | 0,X | 0 | 1/1 | | 80 | 10000000 | ,X+ | 0 | 2/1 |
| 01 | 00000001 | 1,X | 0 | 1/1 | | 81 | 10000001 | ,X++ | 0 | 3/2 |
| 02 | 00000010 | 2,X | 0 | 1/1 | | 82 | 10000010 | ,-X | 0 | 2/1 |
| 03 | 00000011 | 3,X | 0 | 1/1 | | 83 | 10000011 | ,--X | 0 | 3/2 |
| 04 | 00000100 | 4,X | 0 | 1/1 | | 84 | 10000100 | ,X | 0 | 0/0 |
| 05 | 00000101 | 5,X | 0 | 1/1 | | 85 | 10000101 | B,X | 0 | 1/1 |
| 06 | 00000110 | 6,X | 0 | 1/1 | | 86 | 10000110 | A,X | 0 | 1/1 |
| 07 | 00000111 | 7,X | 0 | 1/1 | | 87 | 10000111 | E, X | 0 | 1/1 |
| 08 | 00001000 | 8,X | 0 | 1/1 | | 88 | 10001000 | nn,X | 1 | 1/1 |
| 09 | 00001001 | 9,X | 0 | 1/1 | | 89 | 10001001 | mmnn,X | 2 | 4/3 |
| 0A | 00001010 | 10,X | 0 | 1/1 | | 8A | 10001010 | F,X | 1 | 1/1 |
| 0B | 00001011 | 11,X | 0 | 1/1 | | 8B | 10001011 | D,X | 0 | 4/2 |
| 0C | 00001100 | 12,X | 0 | 1/1 | | 8C | 10001100 | nn,PC | 1 | 1/1 |
| 0D | 00001101 | 13,X | 0 | 1/1 | | 8D | 10001101 | mmnn,PC | 2 | 5/3 |
| 0E | 00001110 | 14,X | 0 | 1/1 | | 8E | 10001110 | W,X | 0 | 4/1 |
| 0F | 00001111 | 15,X | 0 | 1/1 | | 8F | 10001111 | ,W | 0 | 0/0 |
| 10 | 00010000 | -16,X | 0 | 1/1 | | 90 | 10010000 | [,W] | 0 | 3/3 |
| 11 | 00010001 | -15,X | 0 | 1/1 | | 91 | 10010001 | [,X++] | 0 | 6/5 |
| 12 | 00010010 | -14,X | 0 | 1/1 | | 92 | 10010010 | Illegal | 0 | 20/19 |
| 13 | 00010011 | -13,X | 0 | 1/1 | | 93 | 10010011 | [,--X] | 0 | 6/5 |
| 14 | 00010100 | -12,X | 0 | 1/1 | | 94 | 10010100 | [,X] | 0 | 3/3 |
| 15 | 00010101 | -11,X | 0 | 1/1 | | 95 | 10010101 | [B,X] | 0 | 4/4 |
| 16 | 00010110 | -10,X | 0 | 1/1 | | 96 | 10010110 | [A,X] | 0 | 4/4 |
| 17 | 00010111 | -9,X | 0 | 1/1 | | 97 | 10010111 | [E,X] | 0 | 4/4 |
| 18 | 00011000 | -8,X | 0 | 1/1 | | 98 | 10011000 | [nn,X] | 1 | 4/4 |
| 19 | 00011001 | -7,X | 0 | 1/1 | | 99 | 10011001 | [mmnn,X] | 2 | 7/7 |
| 1A | 00011010 | -6,X | 0 | 1/1 | | 9A | 10011010 | [F,X] | 0 | 4/4 |
| 1B | 00011011 | -5,X | 0 | 1/1 | | 9B | 10011011 | [D,X] | 0 | 7/5 |
| 1C | 00011100 | -4,X | 0 | 1/1 | | 9C | 10011100 | [nn,PC] | 1 | 4/4 |
| 1D | 00011101 | -3,X | 0 | 1/1 | | 9D | 10011101 | [mmnn,PC] | 2 | 8/6 |
| 1E | 00011110 | -2,X | 0 | 1/1 | | 9E | 10011110 | [W,X] | 0 | 7/4 |
| 1F | 00011111 | -1,X | 0 | 1/1 | | 9F | 10011111 | [mmnn] | 2 | 5/5 |
| 20 | 00100000 | 0,Y | 0 | 1/1 | | A0 | 10100000 | ,Y+ | 0 | 2/1 |
| 21 | 00100001 | 1,Y | 0 | 1/1 | | A1 | 10100001 | ,Y++ | 0 | 3/2 |
| 22 | 00100010 | 2,Y | 0 | 1/1 | | A2 | 10100010 | ,-Y | 0 | 2/1 |
| 23 | 00100011 | 3,Y | 0 | 1/1 | | A3 | 10100011 | ,--Y | 0 | 3/1 |
| 24 | 00100100 | 4,Y | 0 | 1/1 | | A4 | 10100100 | ,Y | 0 | 0/0 |
| 25 | 00100101 | 5,Y | 0 | 1/1 | | A5 | 10100101 | B,Y | 0 | 1/1 |
| 26 | 00100110 | 6,Y | 0 | 1/1 | | A6 | 10100110 | A,Y | 0 | 1/1 |
| 27 | 00100111 | 7,Y | 0 | 1/1 | | A7 | 10100111 | E,Y | 0 | 1/1 |
| 28 | 00101000 | 8,Y | 0 | 1/1 | | A8 | 10101000 | nn,Y | 1 | 1/1 |
| 29 | 00101001 | 9,Y | 0 | 1/1 | | A9 | 10101001 | mmnn,Y | 2 | 4/3 |
| 2A | 00101010 | 10,Y | 0 | 1/1 | | AA | 10101010 | F,Y | 0 | 1/1 |
| 2B | 00101011 | 11,Y | 0 | 1/1 | | AB | 10101011 | D,Y | 0 | 4/2 |
| 2C | 00101100 | 12,Y | 0 | 1/1 | | AC | 10101100 | nn,PC | 1 | 1/1 |
| 2D | 00101101 | 13,Y | 0 | 1/1 | | AD | 10101101 | mmnn,PC | 2 | 5/3 |
| 2E | 00101110 | 14,Y | 0 | 1/1 | | AE | 10101110 | W,Y | 0 | 4/1 |
| 2F | 00101111 | 15,Y | 0 | 1/1 | | AF | 10101111 | mmnn,W | 2 | 5/2 |
| 30 | 00110000 | -16,Y | 0 | 1/1 | | B0 | 10110000 | [mmnn,W] | 2 | 5/5 |
| 31 | 00110001 | -15,Y | 0 | 1/1 | | B1 | 10110001 | [,Y++] | 0 | 6/5 |
| 32 | 00110010 | -14,Y | 0 | 1/1 | | B2 | 10110010 | Illegal | 0 | 20/19 |
| 33 | 00110011 | -13,Y | 0 | 1/1 | | B3 | 10110011 | [,--Y] | 0 | 6/5 |
| 34 | 00110100 | -12,Y | 0 | 1/1 | | B4 | 10110100 | [,Y] | 0 | 3/3 |
| 35 | 00110101 | -11,Y | 0 | 1/1 | | B5 | 10110101 | [B,Y] | 0 | 4/4 |
| 36 | 00110110 | -10,Y | 0 | 1/1 | | B6 | 10110110 | [A,Y] | 0 | 4/4 |
| 37 | 00110111 | -9,Y | 0 | 1/1 | | B7 | 10110111 | [E,Y] | 0 | 4/4 |
| 38 | 00111000 | -8,Y | 0 | 1/1 | | B8 | 10111000 | [nn,Y] | 1 | 4/4 |
| 39 | 00111001 | -7,Y | 0 | 1/1 | | B9 | 10111001 | [mmnn,Y] | 2 | 7/7 |
| 3A | 00111010 | -6,Y | 0 | 1/1 | | BA | 10111010 | [F,Y] | 0 | 4/4 |
| 3B | 00111011 | -5,Y | 0 | 1/1 | | BB | 10111011 | [D,Y] | 0 | 7/5 |
| 3C | 00111100 | -4,Y | 0 | 1/1 | | BC | 10111100 | [nn,PC] | 1 | 4/4 |
| 3D | 00111101 | -3,Y | 0 | 1/1 | | BD | 10111101 | [mmnn,PC] | 2 | 8/6 |
| 3E | 00111110 | -2,Y | 0 | 1/1 | | BE | 10111110 | [W,Y] | 0 | 7/4 |
| 3F | 00111111 | -1,Y | 0 | 1/1 | | BF | 10111111 | Illegal | 0 | 20/19 |
| 40 | 01000000 | 0,U | 0 | 1/1 | | C0 | 11000000 | ,U+ | 0 | 2/1 |
| 41 | 01000001 | 1,U | 0 | 1/1 | | C1 | 11000001 | ,U++ | 0 | 3/2 |
| 42 | 01000010 | 2,U | 0 | 1/1 | | C2 | 11000010 | ,-U | 0 | 2/1 |
| 43 | 01000011 | 3,U | 0 | 1/1 | | C3 | 11000011 | ,--U | 0 | 3/2 |
| 44 | 01000100 | 4,U | 0 | 1/1 | | C4 | 11000100 | ,U | 0 | 0/0 |
| 45 | 01000101 | 5,U | 0 | 1/1 | | C5 | 11000101 | B,U | 0 | 1/1 |
| 46 | 01000110 | 6,U | 0 | 1/1 | | C6 | 11000110 | A,U | 0 | 1/1 |
| 47 | 01000111 | 7,U | 0 | 1/1 | | C7 | 11000111 | E,U | 0 | 1/1 |
| 48 | 01001000 | 8,U | 0 | 1/1 | | C8 | 11001000 | nn,U | 1 | 1/1 |
| 49 | 01001001 | 9,U | 0 | 1/1 | | C9 | 11001001 | mmnn,U | 2 | 4/3 |
| 4A | 01001010 | 10,U | 0 | 1/1 | | CA | 11001010 | F,U | 0 | 1/1 |
| 4B | 01001011 | 11,U | 0 | 1/1 | | CB | 11001011 | D,U | 0 | 4/2 |
| 4C | 01001100 | 12,U | 0 | 1/1 | | CC | 11001100 | nn,PC | 1 | 1/1 |
| 4D | 01001101 | 13,U | 0 | 1/1 | | CD | 11001101 | mmnn,PC | 2 | 5/3 |
| 4E | 01001110 | 14,U | 0 | 1/1 | | CE | 11001110 | W,U | 0 | 4/1 |
| 4F | 01001111 | 15,U | 0 | 1/1 | | CF | 11001111 | ,W++ | 0 | 3/1 |
| 50 | 01010000 | -16,U | 0 | 1/1 | | D0 | 11010000 | [,W++] | 0 | 4/4 |
| 51 | 01010001 | -15,U | 0 | 1/1 | | D1 | 11010001 | [,U++] | 0 | 6/5 |
| 52 | 01010010 | -14,U | 0 | 1/1 | | D2 | 11010010 | Illegal | 0 | 20/19 |
| 53 | 01010011 | -13,U | 0 | 1/1 | | D3 | 11010011 | [,--U] | 0 | 6/5 |
| 54 | 01010100 | -12,U | 0 | 1/1 | | D4 | 11010100 | [,U] | 0 | 3/3 |
| 55 | 01010101 | -11,U | 0 | 1/1 | | D5 | 11010101 | [B,U] | 0 | 4/4 |
| 56 | 01010110 | -10,U | 0 | 1/1 | | D6 | 11010110 | [A,U] | 0 | 4/4 |
| 57 | 01010111 | -9,U | 0 | 1/1 | | D7 | 11010111 | [E,U] | 0 | 4/4 |
| 58 | 01011000 | -8,U | 0 | 1/1 | | D8 | 11011000 | [nn,U] | 1 | 4/4 |
| 59 | 01011001 | -7,U | 0 | 1/1 | | D9 | 11011001 | [mmnn,U] | 2 | 7/7 |
| 5A | 01011010 | -6,U | 0 | 1/1 | | DA | 11011010 | [F,U] | 0 | 4/4 |
| 5B | 01011011 | -5,U | 0 | 1/1 | | DB | 11011011 | [D,U] | 0 | 7/5 |
| 5C | 01011100 | -4,U | 0 | 1/1 | | DC | 11011100 | [nn,PC] | 1 | 4/4 |
| 5D | 01011101 | -3,U | 0 | 1/1 | | DD | 11011101 | [mmnn,PC] | 2 | 8/6 |
| 5E | 01011110 | -2,U | 0 | 1/1 | | DE | 11011110 | [W,U] | 0 | 7/4 |
| 5F | 01011111 | -1,U | 0 | 1/1 | | DF | 11011111 | Illegal | 2 | 20/19 |
| 60 | 01100000 | 0,S | 0 | 1/1 | | E0 | 11100000 | ,S+ | 0 | 2/1 |
| 61 | 01100001 | 1,S | 0 | 1/1 | | E1 | 11100001 | ,S++ | 0 | 3/2 |
| 62 | 01100010 | 2,S | 0 | 1/1 | | E2 | 11100010 | ,-S | 0 | 2/1 |
| 63 | 01100011 | 3,S | 0 | 1/1 | | E3 | 11100011 | ,--S | 0 | 3/2 |
| 64 | 01100100 | 4,S | 0 | 1/1 | | E4 | 11100100 | ,S | 0 | 0/0 |
| 65 | 01100101 | 5,S | 0 | 1/1 | | E5 | 11100101 | B,S | 0 | 1/1 |
| 66 | 01100110 | 6,S | 0 | 1/1 | | E6 | 11100110 | A,S | 0 | 1/1 |
| 67 | 01100111 | 7,S | 0 | 1/1 | | E7 | 11100111 | E,S | 0 | 1/1 |
| 68 | 01101000 | 8,S | 0 | 1/1 | | E8 | 11101000 | nn,S | 1 | 1/1 |
| 69 | 01101001 | 9,S | 0 | 1/1 | | E9 | 11101001 | mmnn,S | 2 | 4/3 |
| 6A | 01101010 | 10,S | 0 | 1/1 | | EA | 11101010 | F,S | 0 | 1/1 |
| 6B | 01101011 | 11,S | 0 | 1/1 | | EB | 11101011 | D,S | 0 | 4/2 |
| 6C | 01101100 | 12,S | 0 | 1/1 | | EC | 11101100 | nn,PC | 1 | 1/1 |
| 6D | 01101101 | 13,S | 0 | 1/1 | | ED | 11101101 | mmnn,PC | 2 | 5/3 |
| 6E | 01101110 | 14,S | 0 | 1/1 | | EE | 11101110 | W,S | 0 | 4/1 |
| 6F | 01101111 | 15,S | 0 | 1/1 | | EF | 11101111 | ,--W | 0 | 3/1 |
| 70 | 01110000 | -16,S | 0 | 1/1 | | F0 | 11110000 | [,--W] | 0 | 4/4 |
| 71 | 01110001 | -15,S | 0 | 1/1 | | F1 | 11110001 | [,S++] | 0 | 6/5 |
| 72 | 01110010 | -14,S | 0 | 1/1 | | F2 | 11110010 | Illegal | 0 | 20/19 |
| 73 | 01110011 | -13,S | 0 | 1/1 | | F3 | 11110011 | [,--S] | 0 | 6/5 |
| 74 | 01110100 | -12,S | 0 | 1/1 | | F4 | 11110100 | [,S] | 0 | 3/3 |
| 75 | 01110101 | -11,S | 0 | 1/1 | | F5 | 11110101 | [B,S] | 0 | 4/4 |
| 76 | 01110110 | -10,S | 0 | 1/1 | | F6 | 11110110 | [A,S] | 0 | 4/4 |
| 77 | 01110111 | -9,S | 0 | 1/1 | | F7 | 11110111 | [E,S] | 0 | 4/4 |
| 78 | 01111000 | -8,S | 0 | 1/1 | | F8 | 11111000 | [nn,S] | 1 | 4/4 |
| 79 | 01111001 | -7,S | 0 | 1/1 | | F9 | 11111001 | [mmnn,S] | 2 | 7/7 |
| 7A | 01111010 | -6,S | 0 | 1/1 | | FA | 11111010 | [F,S] | 0 | 4/4 |
| 7B | 01111011 | -5,S | 0 | 1/1 | | FB | 11111011 | [D,S] | 0 | 7/5 |
| 7C | 01111100 | -4,S | 0 | 1/1 | | FC | 11111100 | [nn,PC] | 1 | 4/4 |
| 7D | 01111101 | -3,S | 0 | 1/1 | | FD | 11111101 | [mmnn,PC] | 2 | 8/6 |
| 7E | 01111110 | -2,S | 0 | 1/1 | | FE | 11111110 | [W,S] | 0 | 7/4 |
| 7F | 01111111 | -1,S | 0 | 1/1 | | FF | 11111111 | Illegal | 2 | 20/19 |