git.joshuawise.com / fpgaboy.git / blame
| Commit | Line | Data |
|---|---|---|
| a761b30b JW |
1 | |
| 2 | -------------------------------------------------------------------------------- | |
| 3 | | | C Flag | HEX value in | H Flag | HEX value in | Number | C flag | | |
| 4 | | Operation | Before | upper digit | Before | lower digit | added | After | | |
| 5 | | | DAA | (bit 7-4) | DAA | (bit 3-0) | to byte | DAA | | |
| 6 | |------------------------------------------------------------------------------| | |
| 7 | | | 0 | 0-9 | 0 | 0-9 | 00 | 0 | | |
| 8 | | ADD | 0 | 0-8 | 0 | A-F | 06 | 0 | | |
| 9 | | | 0 | 0-9 | 1 | 0-3 | 06 | 0 | | |
| 10 | | ADC | 0 | A-F | 0 | 0-9 | 60 | 1 | | |
| 11 | | | 0 | 9-F | 0 | A-F | 66 | 1 | | |
| 12 | | INC | 0 | A-F | 1 | 0-3 | 66 | 1 | | |
| 13 | | | 1 | 0-2 | 0 | 0-9 | 60 | 1 | | |
| 14 | | | 1 | 0-2 | 0 | A-F | 66 | 1 | | |
| 15 | | | 1 | 0-3 | 1 | 0-3 | 66 | 1 | | |
| 16 | |------------------------------------------------------------------------------| | |
| 17 | | SUB | 0 | 0-9 | 0 | 0-9 | 00 | 0 | | |
| 18 | | SBC | 0 | 0-8 | 1 | 6-F | FA | 0 | | |
| 19 | | DEC | 1 | 7-F | 0 | 0-9 | A0 | 1 | | |
| 20 | | NEG | 1 | 6-F | 1 | 6-F | 9A | 1 | | |
| 21 | |------------------------------------------------------------------------------| | |
| 22 | ||
| 23 | Flags: | |
| 24 | C: See instruction. | |
| 25 | N: Unaffected. | |
| 26 | P/V: Set if Acc. is even parity after operation, reset otherwise. | |
| 27 | H: See instruction. | |
| 28 | Z: Set if Acc. is Zero after operation, reset otherwise. | |
| 29 | S: Set if most significant bit of Acc. is 1 after operation, reset otherwise. |