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SBC (SPC700): Difference between revisions
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{| class="wikitable" style="float:right;clear:right;width: | {| class="wikitable" style="float:right;clear:right;width:45%" | ||
!colspan="8"|Basic Info | !colspan="8"|Basic Info | ||
|+ | |+ | ||
| Line 7: | Line 7: | ||
|'''Speed''' | |'''Speed''' | ||
|+ | |+ | ||
| | |[[Immediate]] | ||
|A8 | |A8 | ||
|2 bytes | |2 bytes | ||
|2 cycles | |2 cycles | ||
|+ | |+ | ||
| | |[[Implied Indirect]] (type 1) | ||
|A6 | |A6 | ||
|1 byte | |1 byte | ||
|3 cycles | |3 cycles | ||
|+ | |+ | ||
| | |[[Direct Page Addressing | Direct Page]] | ||
|A4 | |A4 | ||
|2 bytes | |2 bytes | ||
|3 cycles | |3 cycles | ||
|+ | |+ | ||
| | |[[Direct Page Indexed by X]] | ||
|B4 | |B4 | ||
|2 bytes | |2 bytes | ||
|4 cycles | |4 cycles | ||
|+ | |+ | ||
| | |[[Absolute Addressing | Absolute]] | ||
|A5 | |A5 | ||
|3 bytes | |3 bytes | ||
|4 cycles | |4 cycles | ||
|+ | |+ | ||
| | |[[Absolute Indexed by X]] | ||
|B5 | |B5 | ||
|3 bytes | |3 bytes | ||
|5 cycles | |5 cycles | ||
|+ | |+ | ||
| | |[[Absolute Indexed by Y]] | ||
|B6 | |B6 | ||
|3 bytes | |3 bytes | ||
|5 cycles | |5 cycles | ||
|+ | |+ | ||
| | |[[Direct Page Indexed by X]] | ||
|A7 | |A7 | ||
|2 bytes | |2 bytes | ||
|6 cycles | |6 cycles | ||
|+ | |+ | ||
| | |[[Direct Page Indirect Indexed by Y]] | ||
|B7 | |B7 | ||
|2 bytes | |2 bytes | ||
|6 cycles | |6 cycles | ||
|+ | |+ | ||
| | |[[Implied Indirect]] (type 1) | ||
|B9 | |B9 | ||
|1 byte | |1 byte | ||
|5 cycles | |5 cycles | ||
|+ | |+ | ||
| | |[[Direct Page]] | ||
|A9 | |A9 | ||
|3 bytes | |3 bytes | ||
|6 cycles | |6 cycles | ||
|+ | |+ | ||
| | |[[Direct Page Immediate]] | ||
|B8 | |B8 | ||
|3 bytes | |3 bytes | ||
| Line 71: | Line 71: | ||
!colspan="8"|Flags Affected | !colspan="8"|Flags Affected | ||
|+ | |+ | ||
|N | |[[Negative Flag|N]] | ||
|V | |[[Overflow Flag|V]] | ||
|P | |[[Direct Page Flag|P]] | ||
|B | |[[Break Flag|B]] | ||
|H | |[[Half-Carry Flag|H]] | ||
|I | |[[Interrupt Enable Flag|I]] | ||
|Z | |[[Zero Flag|Z]] | ||
|C | |[[Carry Flag|C]] | ||
|+ | |+ | ||
| | | | ||
| Line 91: | Line 91: | ||
'''SBC''' (Subtract) is an [[SPC700]] instruction that subtracts the right operand and the inverse of the [[carry flag]] from the left operand. Often, the left operand is the [[accumulator]]. | '''SBC''' (Subtract) is an [[SPC700]] instruction that subtracts the right operand and the inverse of the [[carry flag]] from the left operand. Often, the left operand is the [[accumulator]]. | ||
The operands are stored in the instruction stream in the opposite order they appear in the assembler source. In the assembler source, the operand on the right is the source and the operand on the left is the destination. | |||
=== See Also === | === See Also === | ||
* [[ADC (SPC700)]] | * [[ADC (SPC700)]] | ||
* [[SBC]] | * [[SBC]] | ||
* [[SUBW]] | |||
=== External Links === | === External Links === | ||
* Official Super Nintendo development manual on SBC: [https://archive.org/details/SNESDevManual/book1/page/n230 Appendix C-5 of Book I] | * Official Super Nintendo development manual on SBC: Table C-7 in [https://archive.org/details/SNESDevManual/book1/page/n230 Appendix C-5 of Book I] | ||
[[Category:ASM]] | [[Category:ASM]] | ||
[[Category:SPC700]] | [[Category:SPC700]] | ||
[[Category:8-bit Arithmetic Operation Commands]] | [[Category:8-bit Arithmetic Operation Commands]] | ||
Latest revision as of 04:53, 27 November 2023
| Basic Info | |||||||
|---|---|---|---|---|---|---|---|
| Addressing Mode | Opcode | Length | Speed | ||||
| Immediate | A8 | 2 bytes | 2 cycles | ||||
| Implied Indirect (type 1) | A6 | 1 byte | 3 cycles | ||||
| Direct Page | A4 | 2 bytes | 3 cycles | ||||
| Direct Page Indexed by X | B4 | 2 bytes | 4 cycles | ||||
| Absolute | A5 | 3 bytes | 4 cycles | ||||
| Absolute Indexed by X | B5 | 3 bytes | 5 cycles | ||||
| Absolute Indexed by Y | B6 | 3 bytes | 5 cycles | ||||
| Direct Page Indexed by X | A7 | 2 bytes | 6 cycles | ||||
| Direct Page Indirect Indexed by Y | B7 | 2 bytes | 6 cycles | ||||
| Implied Indirect (type 1) | B9 | 1 byte | 5 cycles | ||||
| Direct Page | A9 | 3 bytes | 6 cycles | ||||
| Direct Page Immediate | B8 | 3 bytes | 5 cycles | ||||
| Flags Affected | |||||||
|---|---|---|---|---|---|---|---|
| N | V | P | B | H | I | Z | C |
| . | . | . | |||||
SBC (Subtract) is an SPC700 instruction that subtracts the right operand and the inverse of the carry flag from the left operand. Often, the left operand is the accumulator.
The operands are stored in the instruction stream in the opposite order they appear in the assembler source. In the assembler source, the operand on the right is the source and the operand on the left is the destination.
See Also
External Links
- Official Super Nintendo development manual on SBC: Table C-7 in Appendix C-5 of Book I