Page 135 - DCAP210_INTRODUCTION__TO_MICROPROCESSORS

Unit 9: Introduction to 8085 Instructions

PO: Parity Odd (P = 0) Notes

PE: Parity Even (P = 1)
P: Plus (S = 0)
M: Minus (S = 1)

Thus, the conditional branching instructions are specified as follows:

Jumps Calls Returns
C CC RC (Carry)
INC CNC RNC (No Carry)

JZ CZ RZ (Zero)
JNZ CNZ RNZ (Not Zero)
JP CP RP (Plus)
JM CM RM (Minus)

JPE CPE RPE (Parity Even)
JP0 CPO RPO (Parity Odd)

Two other instructions can affect a branch by replacing the contents or the program counter:
PCHL: Move H & L to Program Counter

RST: Special Restart Instruction Used with Interrupts

Give the difference between conditional and unconditional branching instructions.

9.5 Machine Control Operations
These instructions control machine functions such as Halt, Interrupt, or do nothing. The
microprocessor operations related to data manipulation can be summarized in four functions:

1. Copying data
2. Performing arithmetic operations

3. Performing logical operations
4. Testing for a given condition and alerting the program sequence
Some important aspects of the instruction set are noted below:

1. In data transfer, the contents of the source are not destroyed; only the contents of the destination
are changed. The data copy instructions do not affect the flags.

2. Arithmetic and Logical operations are performed with the contents of the accumulator, and
the results are stored in the accumulator (with some expectations). The flags are affected
according to the results.
3. Any register including the memory can be used for increment and decrement.

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