| Mode |
Assembler example |
Nr.of bytes |
Description |
| Immediate |
ADC #xx |
2 |
The instruction is relative to the value xx. |
| Accumulator |
ASL A |
1 |
The instruction is relative to the accumulator.
This mode exists in instructions that can
operate in memory or in the accumulator. |
| Relative |
BCC xx |
2 |
This mode is used in branch instruction.
The program counter is incremented or
decremented by xx steps, with signal bit. |
| Implied |
INX |
1 |
This mode refers to instructions that
need no arguments, as the value to be
manipulated is implied in the instruction's name |
| Zero Page |
LDA xx |
2 |
One of the most interesting features of the 6502
is the Zero Page addressing. Addresses ranging from
0000 to 00FF can be accessed faster by this special mode. |
| Zero Page,X |
DEC xx,X |
2 |
The value manipulated by the instruction is the one
contained in 00xx added with the content of the X register. |
| Zero Page,Y |
LDX xx,Y |
2 |
The value manipulated by the instruction is the one
contained in 00xx added to the content of Y register. Appears
only in instructions that manipulate the X register. |
| Absolute |
JSR xxxx |
3 |
The instruction is relative to the content of the address xxxx. |
| Absolute,X |
EOR xxxx,X |
3 |
The instruction is relative to the content of the address (xxxx + X). |
| Absolute,Y |
CMP xxxx,Y |
3 |
The instruction is relative to the content of the address (xxxx + Y). |
| (Indirect,X) |
ORA (xx,X) |
2 |
The sum of the xx address and the X register
result in a Zero Page address which contains the effective address. |
| (Indirect),Y |
STA (xx),Y |
2 |
The Zero Page address contains an address
which is added to the value of the Y register
to obtain the effective address. |
| (Indirect) |
JMP (xxxx) |
3 |
The content of the xxxx address will be the address
that will contain the effective address. |
