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Ethernet TX support
[fpgaboy.git] / daa.txt
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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
23Flags:
24C: See instruction.
25N: Unaffected.
26P/V: Set if Acc. is even parity after operation, reset otherwise.
27H: See instruction.
28Z: Set if Acc. is Zero after operation, reset otherwise.
29S: Set if most significant bit of Acc. is 1 after operation, reset otherwise.
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