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DAA (SPC700): Difference between revisions
From SnesLab
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=== External Links === | === External Links === | ||
* Official Super Nintendo development manual on DAA: Table C-14 in [https://archive.org/details/SNESDevManual/book1/page/n233 Appendix C-8 of Book I] | * Official Super Nintendo development manual on DAA: Table C-14 in [https://archive.org/details/SNESDevManual/book1/page/n233 Appendix C-8 of Book I] | ||
* [https://archive.org/details/SNESDevManual/book1/page/n180 page 3-8-2 of Book I] lbid | * [https://archive.org/details/SNESDevManual/book1/page/n180 page 3-8-2 of Book I], lbid | ||
* ares source code, SPC700::instructionDecimalAdjustAdd | * ares source code, SPC700::instructionDecimalAdjustAdd | ||
* anomie: https://github.com/yupferris/TasmShiz/blob/8fabc9764c33a7ae2520a76d80ed7220bb939f12/spc700.txt#L409 | * anomie: https://github.com/yupferris/TasmShiz/blob/8fabc9764c33a7ae2520a76d80ed7220bb939f12/spc700.txt#L409 | ||
Revision as of 14:54, 15 August 2024
| Basic Info | |||||||
|---|---|---|---|---|---|---|---|
| Addressing Mode | Opcode | Length | Speed | ||||
| Accumulator | DF | 1 byte | 3 cycles | ||||
| Flags Affected | |||||||
|---|---|---|---|---|---|---|---|
| N | V | P | B | H | I | Z | C |
| N | . | . | . | . | . | Z | C |
DAA (Decimal Adjust for Addition) is an SPC700 instruction that corrects a BCD sum:
- If either the carry flag is set or the accumulator exceeds 0x99, add 0x60 to the accumulator and set the carry flag.
- Then, if either the half-carry flag is set, or the lower nibble of the accumulator exceeds 0x09, add 0x06 to the accumulator.
The SPC700 has no decimal mode.
Syntax
DAA DAA A
See Also
External Links
- Official Super Nintendo development manual on DAA: Table C-14 in Appendix C-8 of Book I
- page 3-8-2 of Book I, lbid
- ares source code, SPC700::instructionDecimalAdjustAdd
- anomie: https://github.com/yupferris/TasmShiz/blob/8fabc9764c33a7ae2520a76d80ed7220bb939f12/spc700.txt#L409