| Store Accumulator In Memory |
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STA (Store Accumulator In Memory) stores the accumulator into a specified memory address. It is probably the second most-used opcode in 6502 assembly as it stores the most-used register. It is similar in function to STX and STY.
Operation
This pseudo C code shows how the STA opcode functions when it is executed.
STORE(Operand, ACCUMLATOR); // Stores the Accumulator Register into the memory address specified in the operand.
Addressing Modes
| Addressing Mode
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Assembly Language Form
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Opcode
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# Bytes
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# Cycles
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| Zero Page
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STA Operand
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85
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2
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3
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| Zero Page, X
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STA Operand, X
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95
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2
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4
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| Absolute
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STA Operand
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8D
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3
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4
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| Absolute, X
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STA Operand, X
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9D
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3
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4*
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| Absolute, Y
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STA Operand, Y
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99
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3
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4*
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| (Indirect, X)
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STA (Operand, X)
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81
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2
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6
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| (Indirect), Y
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STA (Operand), Y
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91
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2
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5*
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| * Add 1 if page boundary is crossed.
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Examples
