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ADC: Difference between revisions

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=== External Links ===
=== External Links ===
* [[Eyes & Lichty]] page 423, on ADC: https://archive.org/details/0893037893ProgrammingThe65816/page/n449
* [[Eyes & Lichty]] page 423, on ADC: https://archive.org/details/0893037893ProgrammingThe65816/page/423
* [[Labiak]] page 115 on ADC: https://archive.org/details/Programming_the_65816/page/n125
* [[Labiak]] page 115 on ADC: https://archive.org/details/Programming_the_65816/page/n125
* [[MCS6500 Manual]] page 7 on ADC: https://archive.org/details/mos_microcomputers_programming_manual/page/n22
* [[MCS6500 Manual]] page 7 on ADC: https://archive.org/details/mos_microcomputers_programming_manual/page/n22

Revision as of 04:41, 15 July 2024

Basic Info
Addressing Mode Opcode Length Speed
Immediate 69 2/3 bytes 2 cycles*
Absolute 6D 3 bytes 4 cycles*
Absolute Long 6F 4 bytes 5 cycles*
Direct Page 65 2 bytes 3 cycles*
Direct Page Indirect 72 2 bytes 5 cycles*
Direct Page Indirect Long 67 2 bytes 6 cycles*
Absolute Indexed by X 7D 3 bytes 4 cycles*
Absolute Long Indexed by X 7F 4 bytes 5 cycles*
Absolute Indexed by Y 79 3 bytes 4 cycles*
Direct Page Indexed by X 75 2 bytes 4 cycles*
Direct Page Indexed Indirect by X 61 2 bytes 6 cycles*
Direct Page Indirect Indexed by Y 71 2 bytes 5 cycles*
Direct Page Indirect Long Indexed by Y 77 2 bytes 6 cycles*
Stack Relative 63 2 bytes 4 cycles*
Stack Relative Indirect Indexed by Y 73 2 bytes 7 cycles*
Flags Affected
N V M X D I Z C
. . . .

ADC (Add with Carry) is 65x instruction that performs an addition. As there is no add-without-carry instruction, a CLC should be run (or the carry flag otherwise ensured to be clear) before an ADC, or else the sum will be one greater than expected.

The accumulator is always one of the addends. The sum is stored in the accumulator.

After ADC runs, the carry flag will indicate whether the addition caused an unsigned overflow. The zero flag will be set if the sum is zero and cleared otherwise.

If the decimal flag is set, then binary coded decimal addition is performed, otherwise binary addition.

Syntax

ADC #const
ADC addr
ADC long
ADC dp
ADC (dp)
ADC [dp]
ADC addr, X
ADC long, X
ADC addr, Y
ADC dp, X
ADC (dp, X)
ADC (dp), Y
ADC [dp], Y
ADC sr, S
ADC (sr, S), Y

Cycle Penalties

TODO

See Also

External Links