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Stack | Pointer | : Contents | of ACCB | |
Stack | Pointer | : Contents | of CC |
After the status of each register is stored on the stack, the Stack Pointer will be decremented. When the stack is unloaded (status of registers restored), the status of the last register on the stack will be the first register that is restored.
Condition Code Register (CC)
The condition code register is an 8 bit register. Each individual bit may get set or get cleared from execution of an instruction. To see how each instruction effects the condition code register, refer to the M6800 programming manual. The primary use of this register is execution of the conditional branch instruction. Bit 6 and 7 are not used and remain at logic "1."
BIT N0. | FUNCTION |
0C
1V (Overflow Test)
2Z (Zero Test)
3N (Negative Test)
4I (Interrupt Mask Test)
5H (Half Carry Test)