Motorola M6800 manual BIT N0 Function

Page 6

 

 

 

 

MPU-6

Stack

Pointer

Address-5

: Contents

of ACCB

Stack

Pointer

Address-6

: 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 (Carry-Borrow Test)

1V (Overflow Test)

2Z (Zero Test)

3N (Negative Test)

4I (Interrupt Mask Test)

5H (Half Carry Test)

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Contents MPU-1 Introduction MPU-2 MPU-3 MPU-4 MPU-5 BIT N0 Function MPU-7 READ/WRITE R/W Data BUS EnabledbeMPU-8 Valid Memory AddressvmaMPU-9 NON-MASKABLE InterruptnmiBUS Available BA THREE-STATE Control TSC Address BUS AO/A15ADC ABAINS INXPage MPU-14 Summary of MPU Operation Reset Sequence IRQ Sequence NMI Sequence RTI ExecutionSWI Instruction Page Page Page Page Page Page Page Page
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