Each instruction has a one-byte (8-bit) operation codes or opcode. With 8- bit binary opcode, a total of different operation codes can. Intel instruction set. x0, x1, x2, x3, x4, x5, x6, x7, x8, x9, xA, xB, xC, xD, xE, xF. 0x, NOP 1 4 , LXI B,d16 3 10 , STAX B 1 7 , INX B 1 6 –K 1 1 ADDRESSING MODES OF Shown in the following are the sizes of a 5CH This can be verified from the opcode chart given in the previous chapter.
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Store the result in memory locations H and H with the most significant byte in memory location H. Write a program to shift an eight bit data four bits right. Please see Ask Question. Add contents of two memory locations Statement: Store 8-bit data in memory Program 1: My book says that it is a two byte instruction where the first byte is the opcode and the second is the operand.
Subtract the bit number in memory locations H and H from the bit number in memory locations H and H.
That is it has to load data as well as the target register. Assume the least significant digit is stored at H. I was in my foolishness, was desperately trying to separate the opcode into two parts sequentially! In program 2, bit addition instruction DAD is used. Post as a guest Name. The result of both programs will be the same. Read the program given opcod and state the contents of all registers after the execution of each instruction in sequence. Confused about the binary code for the MVI instruction in the instruction o;code.
The most significant eight hcart of the two numbers are in memory locations H and H. Pack the two unpacked BCD numbers stored in memory locations H and H and store result in memory location H.
Terminate program execution NOTE: Subtract the contents of memory location H from the memory location H and place the result in memory location H.
Sign up or log in Sign up using Google. Exchange the contents of memory locations H and H. Subtract two 8-bit numbers Sample problem: The color coding on that chart gives a strong indication of the opcode decoder if the 2 msbits are 00 then if the lower 2 bits are 10 then if bit 2 is a 1 then it is an MVI and bits determine which register.
I am confused as to how exactly the opcode part is converted into machine code. Two digit BCD number is stored in memory location H.
Opcodes of 8085 Microprocessor
How does “3E” tell the microprocessor both the information?
In program 1 direct addressing instruction is used, whereas in program 2 indirect addressing instruction is used. So the opcode if it can be broken down sometimes they dont break down into smaller parts, depends on the instruction set would have to 0885 in that first byte.
Programs For Microprocessor Learners
Add the contents of memory locations Cnart and H and place the result in memory location H. Or is it that this entire opcode is predefined and you can’t separate the “MVI” and “target register” in the opcode? Encoding the target register inside the instruction bits is very common.
Store I6-bit result in memory locations H and H.
Write a program to shift a 16 bit data, 1 bit right. Assume data is in register C. Exchange the contents of memory locations Statement: Program to shift a bit data 1 bit left.
MVI is 0x00xxx where xxx encodes one of 8 possible registers. Assume that data is in BC register pair. Sign up using Email and Password. Add the contents of memory locations H and H and place the result in the memory locations Hand H.