ADC

Basic Info
Addressing Mode	Opcode	Length	Speed
Immediate	69	2 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.

See Also

• SBC
• ADC (SPC700)
• ADC (Super FX)

External Links

• Eyes & Lichty page 423, on ADC: https://archive.org/details/0893037893ProgrammingThe65816/page/n449
• Labiak page 115 on ADC: https://archive.org/details/Programming_the_65816/page/n125
• MCS6500 Manual page on ADC: https://archive.org/details/mos_microcomputers_programming_manual/page/n22
• Carr page on ADC: https://archive.org/details/6502UsersManual/page/n258
• Leventhal page 3-38 on ADC: https://archive.org/details/6502-assembly-language-programming/page/n87
• undisbeliever on ADC: https://undisbeliever.net/snesdev/65816-opcodes.html#adc-add-with-carry