Page 137 - Digital Electronics by harish

Exchange H and L with top of stack
pointer XTHL
XTHL
12.
The contents of the L register are exchanged with the stack location pointed by
the contents of the stack pointer register. The contents of the H register are
exchanged with the next stack location (SP+1).
Push register pair onto stack PUSH B
PUSH Reg. pair PUSH D
(PSW „Processor Status Word‟ means PUSH H
13.
Accumulator and Flag register) PUSH PSW
The contents of the register pair designated in the operand are copied onto the
stack.
POP B
Pop off stack to register pair POP D
POP Reg. pair POP H
14.
POP PSW
The contents of the memory location pointed out by the stack pointer register are
copied to registers specified.

Output data from accumulator to a
port with 8-bit address OUT 50H
15. OUT 8-bit port address
The contents of the accumulator are copied into the I/O port specified by the
operand.
Input data to accumulator from a port
with 8-bit address IN 50H
16. IN 8-bit port address
The contents of the input port designated in the operand are read and loaded into
the accumulator.

5.2.4.2 Arithmetic Instructions

S.No Instruction Example
Add register or memory to
accumulator ADD B
ADD R ADD M
1.
ADD M
The contents of the operand (register or memory) are added to the contents of the
accumulator and the result is stored in the accumulator.
Add register to accumulator with carry ADC B
ADC R ADC M
ADC M
2.
The contents of the operand (register or memory) and the Carry flag are added to
the contents of the accumulator and the result is stored in the accumulator.

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