These instructions are used in order to execute arithmetic instructions like addition, subtraction, multiplication, division, increment or decrement. SHR. This instruction shifts each bit in the specified destination to the left and 0 is stored at LSB position. when working with BCD values. MOV AL, 100b ; Turn on the third OUT 7, AL ; magnet of the stepper-motor. And then a sequence of OUT instructions are used by the 8086 to send the command and data to the 8087? In Operands Example Imm 8, acc OUT 32, AX (OR) OUT PORT, AL DX, acc OUT DX, AL (OR) OUT DX, AX I/O mode (direct) : Port number is an 8 bit immediate operand. Branch Instructions 6. This Paper. OUT DX, AX ; write 16-bit value at the port. instruction queue, address generation unit and bus control unit. Arithmetic and Logical Instructions 3. When immediate is greater then 1, assembler generates several RCL xx, 1 instructions because 8086 has machine code only for this instruction (the same principle works for all other shift/rotate instructions). It jumps to the specified location if the Zero Flag (ZF) is cleared (0). The eight and 16 bit registers are certainly valid operands for this instruction. Loop Instructions in 8086: loop instructions are used to simplify the decrementing, testing and branching portion of the loop. - Arithmetic instructions: As their name suggest these instructions are used to perform arithmetic operations for ex. We will look at 8086 encoding in detail Extension to Pentium instruction is straightforward Encoding of 8086 Instructions 8086 instructions are encoded as binary numbers Instructions vary in length from 1 to 6 bytes Note that many RISC architectures have fixed length instructions Below is the general 2-operand instruction format We will not discuss them all. AL Sends the content of AL to the port with address 48H. Example : MOV reg1, 2. ADD AX, 0100HADD AX, BXADD AX, [SI]ADD AX, [5000H]ADD [5000H], 0100HADD 0100HADC : Add with CarryThis instruction performs the The second operand could be either in a register, memory or a constant value. OUT The OUT instruction transfers a byte from AL or a word from AX to the port. Now lets look at some actual 8086 mov instructions: mov ax, bx ;Copies the value from BX into AX. IN & OUT instructions The IN instruction will copy data from a port to the accumulator. Basically, the status of the result of the operations is reflected by the flag. The MSB is shifted into the carry flag. 1. Example: MOV AX, 1234h PUSH AX POP DX ; DX = 1234h RET C Z S O P A unchanged PUSHA No operands Push all general purpose registers AX, CX, DX, BX, SP, BP, SI, DI in the stack. Data Copy / Transfer Instructions 2. MOV reg/mem,reg/mem! It can be in a register or in a memory location. Every Instruction has a unique 6-bit opcode. The destination can be a register or a memory location. 8086 Microprocessor is an enhanced version of 8085Microprocessor that was designed by Intel in 1976. There are examples of different processors that have the same instruction set.
It works according to the following Algorithm: clear the high nibble of AL. As processor families evolved, more instructions were typically added to the original instruction set. SAL/SHL. There are two basic mechanisms for the processor to service a device. CF OF undefined if count 1 ROR Rotate Right ROR D,Count Rotate the (D) right by the Example: PUSH C. This instruction specifies the transfer of the data present at the top of the stack to the register given as the operand. Microprocessor Multiple Choice Questions on Instruction Set of 8086/8088 1. Clear Carry Flag: This instruction resets the carry flag CF to 0. The instruction will specify the name of the register which holds the data to be operated by the instruction. 8086 Microprocessor is an enhanced version of 8085Microprocessor that was designed by Intel in 1976. ADD, SUB etc. It is confusing, and I may be missing something, but I've tried tonnes of combinations using my two EEPROM chips (Lower and upper byte per chip, even and odd address chips etc.). The flags of the 8086 microprocessor are altered when arithmetic and logical instructions are executed. The AND instruction is used for performing operations on bits. For example fld might be encoded as command 0 and for data the value of rbp-0xc is encoded which the 8087 would know is an address in memory holding the value it needs? 37 Full PDFs related to this paper. Data tranfer instructions are the instructions which transfers data in the microprocessor. The 8086 microprocessor is a16-bit, N-channel, HMOS microprocessor. 5. The 8086 family manual defines the use of rep / repe / repz (0xf3) and repne / repnz (0xf2) prefixes only in conjunction with string instructions, which are movs, cmps, scas, lods and stos; all other uses of those two prefixes are illegal. Data transfer instructions in 8086 microprocessor. Example: MOV DX, 0FE00h ; load DX with the port address. The instruction that is used for finding out the codes in case of code conversion problems is In 8086 microprocessor the following has the highest priority among all type interrupts. Arithmetic Instructions are the instructions which perform basic arithmetic operations such as addition, subtraction and a few more. Each bit shifted out from the left most bit goes back into the rightmost bit position. The arithmetic operations in the 8086 can be categorized as follows: - Data transfer instructions: These types of instructions involve transfer data using commands such as MOV etc. Fig. INSTRUCTION TO PERFORM LOGICAL OPERATION IN 8086 1 Presented by: Rabin BK BSc.CSIT 2nd Semester. Algorithm: shift all bits left, the bit that goes off is set to CF and previous value of CF is inserted to the right-most position. Briefly explain how instruction operations in 8086 can be classified. - Shift instructions: Used for shift operations in special conditions ex. SHL, SHR. - Rotate instructions: They are used to rotate left, right ex. ROL, ROR. instruction-set floating-point 8086. As shown in the Fig. Contents of AL or AX are transferred only between I/O device and microprocessor. This tutorials we will discuss different 8086 microprocessor addressing mode. SAL and SHL are two mnemonics for the same instruction. MOV AL, 100b ; Turn on the third OUT 7, AL ; magnet of the stepper-motor. Microprocessors and Peripherals. Data Transfer Instructions: Data Transfer Instructions defines the data transfer operation. The 8086 provides many arithmetic operations: addition, subtraction, negation,multiplication and comparing two values.ADD :The add instruction adds the contents of the source operand to the destinationoperand.Eg. The source of the word can be a general purpose register, a segment register or memory. Instruction Set 8086 - Free download as Powerpoint Presentation (.ppt), PDF File (.pdf), Text File (.txt) or view presentation slides online. REP Used to repeat the given instruction till CX 0. For example, the opcode for MOV is 100010. It consists of powerful instruction set, which It pushes the operand into top of stack. If 8 bit is read the data will go to AL and if 16 bit then to AX. Where the HMOS is used for " High-speed Metal Oxide Semiconductor ". In 8085 Instruction set, OUT is a mnemonic that stands for OUTput Accumulator contents to an output port whose8-bit address is indicated in the instruction as a8. It occupies 2 Bytes in the memory. Loop Instructions 5. This addressing mode is normally preferred because the instructions are compact and fastest executing of all instruction forms. In this type of architecture, the processor's functional and execution units can work independently and simultaneously. Algorithm for both are same, which The architecture of 8086 can be internally divided into 2 parts. MOV AX,BX - w = 1 because we are dealing with words Flag Manipulation Instructions 8. This instruction bit by bit ORs the source operand with the destination operand The result is stored in the destination operand The general format of the OR instruction is oOR destination, source Eg. The jnz (or jne) instruction is a conditional jump that follows a test. Ecessed using the IN instruction. C: Z: S: O: P: A: unchanged : POP REG 1 instructions because 8086 has machine code only for this instruction (the same principle works for all other shift/rotate instructions). Both IN and OUT instructions can be done using direct and indirect addressing modes. Similar to the IN instruction, the OUT instruction has two forms ixed port and variable port. Unlike in 8085 microprocessor, in 8086 microprocessor the destination operand need not be the accumulator. Answer (1 of 6): 8086 microprocessor has a pipelined architecture. Example: Addressing modes of 8086 are as follows: Immediate addressing mode-. A device indicates that it is ready for a command or data (through some I/O pin or port). An interrupt in 8086 can come from one of the following three sources. The interrupts initiated by applying appropriate signals to Or if you used LAHF: Not funny instructions. Operating frequency= 5 MHz. The opcode and the addressing mode is specified using first two bytes of an instruction. These instructions date 8bit CPUs, They provide 16-bit I/O address space (just 64k addresses). 4) Sources of Interrupts in 8086. String Instructions 7. LSB is placed as a new carry and previous carry is placed as a new MSB. The syntax of this instruction is: The destination operand can be any register or a memory location whereas the source operand can be a register, memory address, or a constant/immediate. The 8086 MOV instruction supports the following operands: This Rotate Instruction in 8086 with example all of the bits in a specified word or byte some number of bit positions to the left along with the carry flag. POP REG SREG 1 instructions because 8086 has machine code only for this instruction (the same principle works for all other shift/rotate instructions). Write an 8086 assembly program that computes the value of Z where. The Shift Instructions in 8086 are follows. FFFF FFFD 0003 0001 D 15 -- D 8 FFFE FFFC 0002 0000 D 7 -- D 0 High bank BHE BLE (A0) FFFB 0005 Low bank FFFA 0004 Data tranfer instructions are the instructions which transfers data in the microprocessor. The first operand in most cases refers to a register or memory. 8086. 1. Address lines define how much memory the processor can access. where D8 is byte displacement from current IP. The processor issues a command to the device, and the device indicates it is busy (not ready). In 8085 Instruction set, OUT is a mnemonic that stands for OUTput Accumulator contents to an output port whose8-bit address is indicated in the instruction as a8. The PUSH instruction decrements stack pointer by two and copies a word from some source to the location in the stack where the stack pointer points. If D=0, then the direction is from the register. Intel 8086 is built on a single semiconductor chip and packaged in a 40-pin IC package. There are 20 address lines for 8086. In this mode, the operand is specified in the instruction itself.
. At the operand an 8 These instructions are used in order to execute arithmetic instructions like addition, subtraction, multiplication, division, increment or decrement. Chapter 2: 8086 Instruction Set and Assembler Directives 1 Machine Language Instruction Format A machine language instruction format has one or more number of fields associated with it. The source can be a register, a. memory location, or an immediate number. Example: 1. Example: MOV AX, 0FFFh ; Turn on all OUT 4, AX ; traffic lights. 8086 Assembly Program for Subtraction of Two 8 bit Numbers; 8086 Assembly Program to Display String hello Implementing JUMP, PUSH, POP, IN & OUT in Assembly Program on 8086; Interrupting BIOS with 8086 Assembly Program; 8086 Assembly Program to Print hello using 09H; 8086 Assembly Program to Search an Element in an Array CLI: Clear Interrupt Flag: This instruction resets the interrupt flag IF to 0. Hi friends, Here i am giving a file which contains Complete Instruction set of 8086 Microprocessor 2 Responses to Complete 8086 Instruction Set with Examples Anonymous said September 11, 2011 at 9:53 AM nice dude. Result is stored in operand1. Here the source must be a word (16 bit). In this case, it is 220=1 Mb memory. These instructions are used in order to execute arithmetic instructions like addition, subtraction, multiplication, division, increment or decrement. For example, every x86-compatible processor can carry out all the instructions of the original Intel 8086 processor. STI: Set interrupt flag IF to 1. Thus, if x is such a processor, and y is the 8086 processor, then xRy. For example: memory, immediate 8086 instructions Page 2 of 53 REG, immediate memory, REG REG, SREG z Some examples contain macros, so it is advisable to use Shift + F8 hot key to Step Over (to make macro code execute at maximum speed set step delay to zero), otherwise emulator will step through each instruction of a macro. 8086 PUSH Instruction. Similar to shift instructions, there are rotate instructions in the 8086 microprocessor where bits of operand are rotated either to the left or right side. CMC: This instruction take complement of carry flag CF. This instruction is useful at the beginning of a loop to bypass the loop if CX = 0. In 8086 microprocessor, the destination operand need not be the accumulator. This instruction has the structure: 100010dw MOD REG R/M Disp1 Disp2 where displacements are optional depending on the MOD bits! EXAMPLE; MOV: D, S: D = S: MOV AX, [SI] PUSH: D: pushes D to the stack: PUSH DX; POP: D: pops the stack to D: POP AS; PUSHA: none: put all the registers into the stack: PUSHA; POPA: none: gets words from the stack to all registers: POPA; XCHG: D, S: exchanges contents of D and S: XCHG [2050], AX; IN: D, S: copies a byte or word from S to D: IN AX, DX; OUT: D, S: CLD: Clear Direction Flag: This instruction resets the direction flag DF to 0. Arithmetic Instructions: 8086 processor can perform four arithmetic operations. Data Movement Instructions IN and OUT IN & OUT instructions perform I/O operations. MOV instruction has seven possible formats. 8086 Instruction Hex Code; Write a program to two add 16 bit Hexadecimal numbers without carry; Write a program to two add 16 bit Hexadecimal numbers with carry; Write a program to find the greatest number from an array of 10 numbers; Write a program to calculate the factorial of a number
