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LDA: Difference between revisions
From SnesLab
(clobbered -> affected) |
(additional cycles) |
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Line 10: | Line 10: | ||
|A9 | |A9 | ||
|2 bytes | |2 bytes | ||
|2 cycles | |2 cycles* | ||
|+ | |+ | ||
|absolute | |absolute | ||
|AD | |AD | ||
|3 bytes | |3 bytes | ||
|4 cycles | |4 cycles* | ||
|+ | |+ | ||
|absolute long | |absolute long | ||
|AF | |AF | ||
|4 bytes | |4 bytes | ||
|5 cycles | |5 cycles* | ||
|+ | |+ | ||
|direct page | |direct page | ||
|A5 | |A5 | ||
|2 bytes | |2 bytes | ||
|3 cycles | |3 cycles* | ||
|+ | |+ | ||
|direct page indirect | |direct page indirect | ||
|B2 | |B2 | ||
|2 bytes | |2 bytes | ||
|5 cycles | |5 cycles* | ||
|+ | |+ | ||
|direct page indirect long | |direct page indirect long | ||
|A7 | |A7 | ||
|2 bytes | |2 bytes | ||
|6 cycles | |6 cycles* | ||
|+ | |+ | ||
|absolute indexed by X | |absolute indexed by X | ||
|BD | |BD | ||
|3 bytes | |3 bytes | ||
|4 cycles | |4 cycles* | ||
|+ | |+ | ||
|absolute long indexed by X | |absolute long indexed by X | ||
|BF | |BF | ||
|4 bytes | |4 bytes | ||
|5 cycles | |5 cycles* | ||
|+ | |+ | ||
|absolute indexed by Y | |absolute indexed by Y | ||
|B9 | |B9 | ||
|3 bytes | |3 bytes | ||
|4 cycles | |4 cycles* | ||
|+ | |+ | ||
|direct page indexed by X | |direct page indexed by X | ||
|B5 | |B5 | ||
|2 bytes | |2 bytes | ||
|4 cycles | |4 cycles* | ||
|+ | |+ | ||
|direct page indexed indirect by X | |direct page indexed indirect by X | ||
|A1 | |A1 | ||
|2 bytes | |2 bytes | ||
|6 cycles | |6 cycles* | ||
|+ | |+ | ||
|direct page indirect indexed by Y | |direct page indirect indexed by Y | ||
|B1 | |B1 | ||
|2 bytes | |2 bytes | ||
|5 cycles | |5 cycles* | ||
|+ | |+ | ||
|direct page indirect long indexed by Y | |direct page indirect long indexed by Y | ||
|B7 | |B7 | ||
|2 bytes | |2 bytes | ||
|6 cycles | |6 cycles* | ||
|+ | |+ | ||
|stack relative | |stack relative | ||
|A3 | |A3 | ||
|2 bytes | |2 bytes | ||
|4 cycles | |4 cycles* | ||
|+ | |+ | ||
|stack relative indirect indexed by Y | |stack relative indirect indexed by Y | ||
|B3 | |B3 | ||
|2 bytes | |2 bytes | ||
|7 cycles | |7 cycles* | ||
|} | |} | ||
Line 105: | Line 105: | ||
|} | |} | ||
'''LDA''' (Load Accumulator) is a 65x instruction that loads the accumulator. | '''LDA''' (Load Accumulator) is a 65x instruction that loads the accumulator. In all [[addressing modes]], LDA takes one extra cycle when the accumulator is 16 bits wide. | ||
=== See Also === | === See Also === |
Revision as of 00:06, 20 November 2023
Basic Info | |||||||
---|---|---|---|---|---|---|---|
Addressing Mode | Opcode | Length | Speed | ||||
immediate | A9 | 2 bytes | 2 cycles* | ||||
absolute | AD | 3 bytes | 4 cycles* | ||||
absolute long | AF | 4 bytes | 5 cycles* | ||||
direct page | A5 | 2 bytes | 3 cycles* | ||||
direct page indirect | B2 | 2 bytes | 5 cycles* | ||||
direct page indirect long | A7 | 2 bytes | 6 cycles* | ||||
absolute indexed by X | BD | 3 bytes | 4 cycles* | ||||
absolute long indexed by X | BF | 4 bytes | 5 cycles* | ||||
absolute indexed by Y | B9 | 3 bytes | 4 cycles* | ||||
direct page indexed by X | B5 | 2 bytes | 4 cycles* | ||||
direct page indexed indirect by X | A1 | 2 bytes | 6 cycles* | ||||
direct page indirect indexed by Y | B1 | 2 bytes | 5 cycles* | ||||
direct page indirect long indexed by Y | B7 | 2 bytes | 6 cycles* | ||||
stack relative | A3 | 2 bytes | 4 cycles* | ||||
stack relative indirect indexed by Y | B3 | 2 bytes | 7 cycles* |
Flags Affected | ||||||||
---|---|---|---|---|---|---|---|---|
N | V | M | X | D | I | Z | C | |
. | . | . | . | . | . |
LDA (Load Accumulator) is a 65x instruction that loads the accumulator. In all addressing modes, LDA takes one extra cycle when the accumulator is 16 bits wide.
See Also
External Links
- Eyes & Lichty page on LDA: https://archive.org/details/0893037893ProgrammingThe65816/page/n488
- Labiak page on LDA: https://archive.org/details/Programming_the_65816/page/n159
- MCS6500 Manual page on LDA: https://archive.org/details/mos_microcomputers_programming_manual/page/n19
- Carr page on LDA: https://archive.org/details/6502UsersManual/page/n276
- Leventhal page on LDA: https://archive.org/details/6502-assembly-language-programming/page/n120
- snes9x implementation of LDA: https://github.com/snes9xgit/snes9x/blob/master/cpuops.cpp#L678
- undisbeliever on LDA: https://undisbeliever.net/snesdev/65816-opcodes.html#lda-load-accumulator-from-memory