ADC是进位加法指令( Add with Carry)的缩写符。
A,Z,C,N = A + M +C
该指令将一个内存地址中的内容与进位一起加到累加器中。如果发生溢出,则设置进位标志,这将允许执行多字节加法。
指令执行后处理器状态:
缩写 | 状态标志名称 | 变化情况 |
---|---|---|
C | Carry Flag | Set if overflow in bit 7 |
Z | Zero Flag | Set if A = 0 |
I | Interrupt Disable | Not affected |
D | Decimal Mode Flag | Not affected |
B | Break Command | Not affected |
V | Overflow Flag | Set if sign bit is incorrect |
N | Negative Flag | Set if bit 7 set |
寻址方式(Addressing Mode) | 操作码(Opcode) | 字节数(Bytes) | 循环位数(Cycles) |
---|---|---|---|
Immediate | $69 | 2 | 2 |
Zero Page | $65 | 2 | 3 |
Zero Page,X | $75 | 2 | 4 |
Absolute | $6D | 3 | 4 |
Absolute,X | $75 | 2 | 4(+1 if page crossed) |
Absolute,Y | $75 | 2 | 4(+1 if page crossed) |
(Indirect,X) | $61 | 2 | 6 |
(Indirect,Y) | $71 | 2 | 5(+1 if page crossed) |
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