The 8086 has complete 16-bit architecture - 16-bit internal registers, 16-bit data bus, and 20-bit address bus (1 MB of physical memory). Physical memory: memory as viewed by the hardware designer. We use cookies to make interactions with our website easy and meaningful, to better understand the use of our services, and to tailor advertising. The 8086 can read a 16-bit word at an even address in one operation and at an odd address in two operations. The Intel 80286 introduced a second version of segmentation in 1982 that added support for virtual memory and memory protection. World's Most Famous Hacker Kevin Mitnick & KnowBe4's Stu Sjouwerman Opening Keynote - Duration: 36:30. Logical Address & Physical Address » 3 types of addresses in 8086: 1. This would seem to suggest that the 8086 can address up to 2^32 bytes, or 4 GB, since 32 bits are used for each address. The condition flags are written directly to the end of each operation performed by the processor. Interrupt is the method of creating a temporary halt during program execution and allows peripheral devices to access the microprocessor. Microprocessor 8086 is the first in its family to get more popular than other microprocessor. 8086's BIU produces the 20-bit physical memory address by combining a 16-bit segment address with a 16-bit offset address. It is a physical addressing scheme that takes into account the limitation of the registers to the 16 bits of the processor architecture, while offering a larger address bus. Effective Address: The address which is generated by a program is called an effective address. , Physical address = ( Segment base*10H ) + Offset Value. These segments are • Code Segment (CS) • Stack Segment (SS) • Data Segment (DS) • Extra Segment (ES) Each S. The lower 16 bits of addresses are multiplexed on the data bus. This address is formed by adding an appended 16 bit segment address and a 16 bit offset address. In computing, a physical address (also real address, or binary address), is a memory address that is represented in the form of a binary number on the address bus circuitry in order to enable the data bus to access a particular storage cell of main memory, or a register of memory mapped I/O device. The physical address is loaded into the memory-address register of the memory. To calculate a physical address, you take the address (called the logical address) and add it to the segment address. Once the physical page number had been found, the physical address of the start of that page is found by multiplying the physical page number by the page size. Caring relationships are the foundation of our work. To calculate the addresses 8086 adds the contents of a register BX or a pointer type to that contained in asegment register shifted to the left of 4 positions. ¾the memory is organized as a set of segments ¾Each segment of memory is a linear contiguous sequence of up to 64K bytes In this segmented memory organization, we have to specify two components to. It is a physical addressing scheme that takes into account the limitation of the registers to the 16 bits of the processor architecture, while offering a larger address bus. The Intel 8088, released July 1, 1979, is a slightly modified chip with an external 8-bit data bus (allowing the use of cheaper and fewer supporting ICs), and is notable as the processor used in the original IBM PC design. It is used by fetch or store location. PHYSICAL ADDRESS: The Watermark Business Park, 1st Floor, Riverina Court, Ndege Road, Off Langata Road Karen, Nairobi Kenya. Physical address: segment * 10H + offset • A4FB*10h + 4872 = A4FB0 + 4872 = A9822h (20-bit address) Physical address maps to several logical addresses • physical address 1256Ah=1256:000Ah=1240:016Ah 29 COE-KFUPM Memory Segmentation - Cont. phone: +254 722 55 4989 / +254 733 55 4989 / 020 251 8086 / 020 251 8096. The logic behind this is to save number of pins. By defaultBX, SI andDI registers work withDS segment register; BP andSP work with SS segment register. UNIT-1 INTRODUCTION TO 8086 ECE DEPARTMENT MICROPROCESSORS AND MICROCONTROLLERS Page 2 iv) ADDRESS BUS: The address bus consists of 16, 20, 24, or more parallel signal lines. •Thus the physical address of the logical address A4FB:4872 is: A4FB0 + 4872 A9822 Prof. same 16 lines are used for both address and data transfer operations (named AD0 to AD15). Every memory reference on the 8086 will use one of the segment registers (i. , 1 MB address in the memory. There are four 16-bit segment registers, viz. SBA stand for: a. The effective address is extended with four high order zeros and added to the base to form a linear address as Figure 14-1 illustrates. Thus, is able to access 2 20 i. The 8086-80286 microprocessors allow four memory segments and the 80386 and above allow six memory segments. The internal registers of 8086/8088 processors are 16-bit (4 hex digit) wide, whereas the 1MBytemain memory locations require 20bit (5 hex digit) wide physical address (PA). During resetting, all internal register contents are set to 0000 H, but CS is set to F000 H and IP to FFF0 H. On these lines the CPU sends out the address of the memory location that is to be written to or read from. 8086/8088 16-bit Microprocessor Launched in 1978 16-bit Data bus 20-bit Address bus. This 1MB memory is divided into 16 logical segments, each with a memory of 64KB. Real Mode: identical to 8086. Dear Readers, Welcome to 8086 Microprocessor Objective Questions have been designed specially to get you acquainted with the nature of questions you may encounter during your Job interview for the subject of 8086 Microprocessor MCQs. It has 14 16-bit registers. The Effective Address. As you noted, the physical page is determined by the translation table, indexed using the logical (virtual) address. We look forward to being of service - always. So 8086 can address the locations ranging between 00000 H to FFFFF H. Thus EPROM in 8086 is interfaced so as to have the physical memory location forms FFFF0 H to FFFFF H, i. 8086 has a 20 bit address bus can access up to 2 20 = 1 MB memory locations. From the given data Physical address= 1005*10H+ 5555H = 155A5H. Segmentation was introduced on the Intel 8086 in 1978 as a way to allow programs to address more than 64 KB (65,536 bytes) of memory. The physical address - is the 20-bit address that is actually put on the address pins of the 8086 microprocessor and decoded by memory interfacing circuitry (00000H - FFFFFH) 2. Real Mode: identical to 8086. Advanced Microprocessors and. Hardware interrupt is caused by any peripheral device by sending a signal through a specified pin to the microprocessor. There are some other differences between the logical and physical address. BUS INTERFACE UNIT (BIU) The bus interface unit contains the circuit for physical address calculations and a pre-decoding instruction byte queue (6 bytes long). Intel 8086 has 20 lines address bus. The address-object transfers - load effective address and load pointer - are an 8086 facility not present in the 8080. It is used the 8086 processor. The real-address mode of the 80386 executes object code designed for execution on 8086, 8088, 80186, or 80188 processors, or for execution in the real-address mode of an 80286: In effect, the architecture of the 80386 in this mode is almost identical to that of the 8086, 8088, 80186, and 80188. eg:- MOV CX,START MOV START,BL START can be defined as an address by using the assembler DB(Define Byte) or DW(Define Word. This value must be offset from (added to) the segment base address in CS to produce the required 20-bit physical address. , in one memory location an 8-bit binary information can be stored). Real Address Mode. Segment: Offset Memory address Since all registers in the 8086 are 16 bits wide, the address space is limited to 216, or 65,536 (64 K) locations. Parking for all those who are not patients or visitors of patients is $10, however free or reduced-price…. However, its registers and memory locations which contain logical addresses are just 16-bits wide. The 8086 and 8088 Central Processing Units Processor Overview Processor Architecture - Execution Unit - Bus Interface Unit - General Registers - Segment Register - Instruction Pointer - Flags - 8080 /8085 Register and Flag Correspondance - Mode Selection Memory -Storage Organization - Segmentation - Physical address Generation. why is it so?. the BIOS, operating systems, and some specialized utility programs (e. 4) Register based indirect addressing mode • In this mode, the effective address of the memory may be taken directly from one of the base register or index register specified by instruction. The 8086 (also called iAPX 86) is a 16-bit microprocessor chip designed by Intel between early 1976 and June 8, 1978, when it was released. , the code segment (CS), the stack segment (SS), the extra segment (ES), and the data segment (DS). Each byte has a specific address. Whenever the 8086 executes an IN and OUT instruction to access a port, none of the segment registers are involved in producing the physical address sent out by the 8086. The 8086 has a 20 bit address bus, so it can address any one of 220, or 1,048,576 memory locations. Multitasking and protection capability are the two key characteristics of 80386 microprocessor. Explanation: Physical address = segment address*10H + offset address (or) shift the segment address by four bits to its left and then add the offset address. of Physical lines to carry-out the address are 20) these lines are nothing but 8086-pins. Log in to reply to the answers Post;. Addressing Modes • When the 8088 executes an instruction, it performs the specified function on data • These data, called operands, - May be a part of the instruction - May reside in one of the internal registers of the microprocessor - May be stored at an address in memory • Register Addressing Mode - MOV AX, BX - MOV ES,AX. • For example, the physical address of the next instruction to. 16 MB of physical memory, 1 GB of virtual memory. Intel 8086 has 20 lines address bus. Problems on physical address calculation in 8086 Microprocessor. Interfacing Limitations of the 8-bit Microprocessor. ) reside in the high bank. The 8086 can read a 16-bit word at an even address in one operation and at an odd address in two operations. Explain the functions of BIU and EU. Note that the 8086 contains 20 address pins, so the physical address size is 20. Protected Mode. General Bus Operation: The 8086 has a combined address and data bus commonly referred as a time multiplexed address and data bus. To generate this 20 bit physical address from 2 sixteen bit registers, the following procedure is adopted. The 8088 needs two operations in either case. com Memory Segmentation In 8086, memory has four different types of segments. Hence, the physical memory space of the 8086 is 1Mb (1 Mega-byte). t a) code segment and b) any other segment 46. 8088/8086 Effective Address (EA) Calculation Description Clock Cycles Displacement 6 Base or Index (BX,BP,SI,DI) 5 Displacement+(Base or Index) 9 Base+Index (BP+DI,BX+SI) 7 Base+Index (BP+SI,BX+DI) 8 Base+Index+Displacement (BP+DI,BX+SI) 11 Base+Index+Displacement (BP+SI+disp,BX+DI+disp) 12 - add 4 cycles for word operands at odd addresses - add 2 cycles for segment override - 80188/80186. There are four 16-bit segment registers, viz. , 1 MB address in the memory. The meaning of ALE is address latch enable. O Box 104670-00101 Nairobi, Kenya. Instruction −8085 doesn'thave an instruction queue, whereas 8086 has an instruction queue. These lines are labelled as AD0-AD7. 80386 Microprocessor is a 32-bit processor that holds the ability to carry out 32-bit operation in one cycle. 220 = 1,048,576 bytes (1 MB). Real Address Mode. Finds the physical address of that location in the memory where the instruction is stored and Manages the 6-byte pre-fetch queue where the pipelined instructions are stored. •It can support up to 64K I/O ports. In 8086 we have base registers and index registers. It belongs to a specific block of memory. The 8086 design could have been extended to a 16MiB address space in a fashion compatible with most existing code, and the 80386 design would have benefited from a mode where the lower portion (maybe 28 bits) of 32-bit segment descriptors would be shifted by an amount controlled by the upper portion. Address Bus −8085 has 16-bit address bus while 8086 has 20-bit address bus. What is the difference between logical and physical address in 8086? Find answers now! No. Advertised as a "source-code compatible" with Intel 8080 and Intel 8085 processors, the 8086 was not object code compatible with them. Memory Segmentation. If the first byte of the word is at an odd address, the 8086 will read the first byte in one operation, and the second byte in another. The physical address of the Internal Architecture of 8086 is 20-bits wide to access 1 Mbyte memory locations. It is the highest data carrying capacity of 8086. Intel 8086 has 20 lines address bus. Question: I Am Sharing You A Question From The Subject Modern Micro Processor 8086 1) Assume That The Physical Address For A Location Is 0046CH, Suggest A Possible Logical Address ( Answer Is 0042:004C) ( Kindly Show All Calculations In Proper Steps And Label Steps As 1, 2, 3 And So On And Plz Also Tell Its Vice Virsa, How To Find Physical Address From Logical. 80386 Microprocessor is a 32-bit processor that holds the ability to carry out 32-bit operation in one cycle. • In virtual mode, 8086 can address 1Mbytes of physical memory that may be anywhere in the 4Gbytes address space of the protected mode of 80386. Ø Each segment thus contains 64 KB of memory. Cyber Investing Summit. To specify where in 1 MB of processor memory these 4 segments are located the 8086 microprocessor uses four segment registers: Code segment (CS) is a 16-bit register containing address of 64 KB segment with processor instructions. 8086 Microprocessor. The i8255 was also used with the Intel 8085 and Intel 8086 and their descendants and found wide applicability in digital. The 8086 and 8088 Central Processing Units Processor Overview Processor Architecture - Execution Unit - Bus Interface Unit - General Registers - Segment Register - Instruction Pointer - Flags - 8080 /8085 Register and Flag Correspondance - Mode Selection Memory -Storage Organization - Segmentation - Physical address Generation. • It has multiplexed address and data bus AD0- AD15 and A16 - A19. Microprocessor 8086 is the first in its family to get more popular than other microprocessor. To specify where in 1 MB of processor memory these 4 segments are located the 8086 microprocessor uses four segment registers: Code segment (CS) is a 16-bit register containing address of 64 KB segment with processor instructions. I learnt that the physical address is calculated by shifting the segment address (16-bit) left 4 times and adding it with the 16-bit offset address. Real Mode: identical to 8086. I think 8086 should be much faster than 8088, since it has 16 bit data bus it can fetch 16 bit data at a time, when compared to 8088 which can fetch only 8 bit data from the memory. com - id: 2244f9-Y2FlO 8086 Addressing Modes - To display this on the screen, we need Three. It can support up to 64K I/O ports. In 8086 we have base registers and index registers. Addresses within a segment can range from address 00000h to address 0FFFFh. The logic behind this is to save number of pins. It is a physical addressing scheme that takes into account the limitation of the registers to the 16 bits of the processor architecture, while offering a larger address bus. Finds the physical address of that location in the memory where the instruction is stored and Manages the 6-byte pre-fetch queue where the pipelined instructions are stored. Microprocessor-based System Design Ricardo Gutierrez-Osuna Wright State University 6 Partial address decoding g Let's assume the same microprocessor with 10 address lines (1KB memory) n However, this time we wish to implement only 512 bytes of memory n We still must use 128-byte memory chips n Physical memory must be placed on the upper half of the memory map. (The linear address is equivalent to the physical address, because paging is not used in real-address mode. Aaradhana A. ; It is used by fetch or store location. Explanation: Physical address = segment address*10H + offset address (or) shift the segment address by four bits to its left and then add the offset address. And so it can address 2^20 different addresses. In this, Actual physical address format is difficult to. Pipelining −8085 doesn'tsupport a pipelined architecture while 8086 supports a. We look forward to being of service - always. |Interestingly I am writing a Z80 emulation at the moment. 8088/8086 Effective Address (EA) Calculation Description Clock Cycles Displacement 6 Base or Index (BX,BP,SI,DI) 5 Displacement+(Base or Index) 9 Base+Index (BP+DI,BX+SI) 7 Base+Index (BP+SI,BX+DI) 8 Base+Index+Displacement (BP+DI,BX+SI) 11 Base+Index+Displacement (BP+SI+disp,BX+DI+disp) 12 - add 4 cycles for word operands at odd addresses - add 2 cycles for segment override - 80188/80186. The CPU (or other device) can use the code to access the corresponding memory location. in 8086 microprocessor a 20 bit address is divided in 16bit+4bit address in which 4 bit binary is the segment address. A physical address is also known as a binary address or a real address. 8086 addresses via its A0-A19 address lines. Log in to reply to the answers Post;. both the banks have equal no. The following image shows the types of interrupts we have in a 8086 microprocessor −. ALU:- ALU is used to perform arithmetic and logical operations Address generator: - This unit is used to generate 20 bit physical address by adding 16 bit logical address displacement with base address. 8086 provides an instruction pointer (IP) which holds the 16-bit address of the next code byte within the code segment. It’s 20 bit address bus can address 1MB of memory, it segments it into 4 64kB segments. 1 decade ago. It is used the 8086 processor. 8086 has 20bit address line. Thus has the ability to address 4 GB (or 2 32) of physical memory. Privilege Levels. The processor uses CS segment. In this article, we are going to solve some problems on calculating the physical address (also known as effective address) of 20 bits using the different segment registers and their respective offsets. Calculate the physical address given following 8086 register contents :1)SS=7698h SP=01FFh 2)CS=5526h IP=8874h. - Each of 1 MB memory address of 8086 represents a byte wide location - 16bit words will be stored in two consecutive Memory location - If first byte of the data is stored at an even address , 8086 can read the entire word in one operation. Each byte has a specific address. 8086/8088 16-bit Microprocessor Launched in 1978 16-bit Data bus 20-bit Address bus. Low speed of execution Low memory addressing capability Limited number of general purpose registers Less powerful instruction set. Since the logical address space consists of 8 = 2 3 pages, the logical addresses must be 10+3 = 13 bits. The lower 16 - bit address lines and 16 - bit data lines are multiplexed (AD0 - AD15). 4) Register based indirect addressing mode • In this mode, the effective address of the memory may be taken directly from one of the base register or index register specified by instruction. Whenever the 8086 executes an IN and OUT instruction to access a port, none of the segment registers are involved in producing the physical address sent out by the 8086. 8086 Microprocessor is a 16-bit microprocessor. Let us discuss them with the help of comparison chart shown below. It provides 14, 16 -bit registers. We have also seen how the 8086 accesses the stack using SS and SP. If you turn off paging, the output from the segmentation unit is already a physical address; in 16-bit real mode that is always the case. 8255 Programmable Peripheral Interface(PPI)-The Intel 8255 (or i8255) programmable peripheral interface (PPI) chip was developed and manufactured by Intel in the first half of the 1970s for the Intel 8080 microprocessor and is a member of the MCS-85 Family of chips. Software Architecture of the 8086 Microprocessor 2-1 MICROARCHITECTURE OF THE 8086 MICROPROCESSOR: The microarchitecture of a microprocessor is its internal architecture that is, the Offset address Physical address 0023 002C3 4900 0A23 49A23 1820 FE00 28000. Data bytes associated with an even address (0000016, 0000216, etc. and the Instruction Pointer (IP) will be discussed along with 8086 memory. - By multiplexed we mean that the same pysical pin carries an address bit at one time and the data bit another time • Address lines A0-A15 and Data lines D0-D15 are multiplexed in 8086. ALE (Address Latch Enable): On both the 8086 and 8088 processors the address and data buses are multiplexed. Similarly, since there are 32 = 2 5 physical pages, phyiscal addresses are 5 + 10 = 15 bits long. These objective type 8086 Microprocessor Questions are very important for campus placement test and job. Problems on physical address calculation in 8086 Microprocessor In this article, we are going to solve some problems on calculating the physical address (also known as effective address) of 20 bits using the different segment registers and their respective offsets. 1 Questions & Answers Place. The four segment registers actually contain the upper 16 bits of the starting addresses of the four memory segments of 64 KB each with which the 8086 is working at that instant of time. But this differs with addressing in our Computer Organisation. Discuss the two pins (a) DT/ R and (b) DEN. of Physical lines to carry-out or carry-in are 16 lines some time ALU size also) and 20-bit Address Bus(20-bit Address Bus means : no. One more interrupt pin associated is INTA called interrupt acknowledge. Favourite answer. 8086 provides an instruction pointer (IP) which holds the 16-bit address of the next code byte within the code segment. On these lines the CPU sends out the address of the memory location that is to be written to or read from. , 1 MB address in the memory. The least significant byte of a word on an 8086 family microprocessor is at the lower address. Address Generation Circuit-The BIU has a Physical Address Generation Circuit. For example, if you wanted to calculate the physical address which relates to logical address "1356" in the stack segment - you would also need to know what value is in the SS register, lets assume "2345":. General Bus Operation: The 8086 has a combined address and data bus commonly referred as a time multiplexed address and data bus. Note that the 80386 and above have a far greater selection of segment offset address combinations than do the 8086 through the 80286 microprocessors. Intel 8086 has 20 lines address bus. The Intel 8086 is a 16-bit microprocessor intended to be used as the CPU in a microcomputer. It can support up to 64K I/O ports. The four segment registers actually contain the upper 16 bits of the starting addresses of the four memory segments of 64 KB each with which the 8086 is working at that instant of time. _______ is the most important segment and it contains the actual assembly language instructions to be executed by the microprocessor. The 8086 (also called iAPX 86) is a 16-bit microprocessor chip designed by Intel between early 1976 and June 8, 1978, when it was released. Thus has the ability to address 4 GB (or 2 32) of physical memory. What are the conditions under which the EU enter into the WA. Segment : Offset Address •Logical Address is specified as segment:offset •Physical address is obtained by shifting the segment address 4 bits to the left and adding the offset address. To locate any adress in the memory bank, it needs the Physical address of that memory. But this differs with addressing in our Computer Organisation. ; It is used by fetch or store location. Logical address, base segment address and physical address. It generates the 20 bit physical address using Segment and Offset addresses using the formula: Physical Address = Segment Address x 10H + Offset Address; 6 Byte Pre-fetch Queue-It is a 6 byte first in first out (FIFO) RAM used to implement pipelining. , Code Segment register, Data Segment register, Extra. The physical address of the Internal Architecture of 8086 is 20-bits wide to access 1 Mbyte memory locations. We use cookies to make interactions with our website easy and meaningful, to better understand the use of our services, and to tailor advertising. It has data and address bus of 32-bit each. • It provides 14, 16-bit registers. But 8086 can access at a time only memory. On these lines the CPU sends out the address of the memory location that is to be written to or read from. The Microprocessor 8086 is a 16-bit CPU. The 8086 has two hardware interrupt pins, i. But with the clever use of segmentation, the address space can be expanded to 1 Megabyte. the BIOS, operating systems, and some specialized utility programs (e. In regards to Covid-19, We are reviewing the best guidelines for our city and state for how. There are two levels of indirection in address translation by the paging unit. Segment: Offset Memory address Since all registers in the 8086 are 16 bits wide, the address space is limited to 216, or 65,536 (64 K) locations. an odd bank and an even bank. With 20 address lines, the memory that can be addressed is 220 bytes. of locations. It is used the 8086 processor. I learnt that the physical address is calculated by shifting the segment address (16-bit) left 4 times and adding it with the 16-bit offset address. The 4 segments are Code, Data, Extra and Stack segments. The basic memory word size of the memories used in the 8086 system is 8-bit or 1-byte (i. World's Most Famous Hacker Kevin Mitnick & KnowBe4's Stu Sjouwerman Opening Keynote - Duration: 36:30. This 1MB memory is divided into 16 logical segments, each with a memory of 64KB. How to calculate Physical Address: Logical Address = Segment : Offset … The 16-bit segment, 16-bit offset. The physical address is then 20bit. 3G physical arrangements that you see have to do with needing to keep some of the lower 4G open for PCI devices, VGA buffers, classic <1M 8086 crap, etc. CPU makes a calculation of physical address by multiplying the segment register by 10h and adding general purpose register to it (1230h * 10h + 45h = 12345h): The address formed with 2 registers is called aneffective address. , Physical address = ( Segment base*10H ) + Offset Value. Memory −8085 can access up to 64Kb, whereas 8086 can access up to 1 Mb of memory. The 8086 design could have been extended to a 16MiB address space in a fashion compatible with most existing code, and the 80386 design would have benefited from a mode where the lower portion (maybe 28 bits) of 32-bit segment descriptors would be shifted by an amount controlled by the upper portion. Segmentation. BE HAPPY - - - JAAAY HANUMAN ( Collect!on of MUS!C , Action Scenes , News , Tragedy Songs , Devotional Songs , Message Oriented Topics , Motivational & Inspirational Speeches , Pathetic Songs , Patriotic Songs , Life Stories …. What is the difference between logical and physical address in 8086? Find answers now! No. If i write the instruction [code]mov AX , $0005 [/code]Then the contents of register AX will be written to RA. FFFF0 + FFFF. It has instruction queue which stores instructions as six bytes thus increasing the processing speed. , the code segment (CS), the stack segment (SS), the extra segment (ES), and the data segment (DS). The address generated by CPU is called a logical address, and the address seen by the memory unit is called a physical address. Thus, 10FFEFh was mapped to FFEFh. • In virtual mode, 8086 can address 1Mbytes of physical memory that may be anywhere in the 4Gbytes address space of the protected mode of 80386. , memory testers), address physical memory. Hence 8086 uses memory segmentation. , more than 1M. 2power20= 1,048,576 bytes (1 MB). It is also known as the offset address or the effective address. Sub: 8086 VIVA QUESTIONS Explain how to generate the physical address w. Data bytes associated with an even address (0000016, 0000216, etc. The four segment registers actually contain the upper 16 bits of the starting addresses of the four memory segments of 64 KB each with which the 8086 is working at that instant of time. Microprocessor-based System Design Ricardo Gutierrez-Osuna Wright State University 6 Partial address decoding g Let's assume the same microprocessor with 10 address lines (1KB memory) n However, this time we wish to implement only 512 bytes of memory n We still must use 128-byte memory chips n Physical memory must be placed on the upper half of the memory map. Cyber Investing Summit. (ii)Calculate effective address (EA) and physical address (PA) in various addressing modes if :. Mention (a) the address capability of 8086 and (b) how many I/O lines can be accessed by 8086. Memory (cont. Memory address translation in x86 CPUs with paging enabled. The number of address lines determines. Thus has the ability to address 4 GB (or 2 32) of physical memory. The physical address is loaded into the memory-address register of the memory. The _____ address of a memory is a 20 bit address for the 8086 microprocessor: a. (b) Which of these two addresses is put on the address bus by the 8086/8088 central processing unit (CPU) to be decoded by the memory circuitry?. Physical Address: In IT, a physical address refers to either a memory location, identified in the form of a binary number, or a media access control (MAC) address. my question is when we encounter the problem of calculating the physical address from the logical, a 4bit hexadecimal segment address is given. This is done by the north bridge. The 8086 can read a 16-bit word at an even address in one operation and at an odd address in two operations. One more interrupt pin associated is INTA called interrupt acknowledge. Introduction To Segmentation: The 8086 microprocessor has 20 bit address pins; these are capable of addressing 1MegaByte memory. interrupt of 8086 is enabled and if it is reset, the interrupt is disabled. The 8086 can read a 16-bit word at an even address in one operation and at an odd address in two operations. , Physical address = ( Segment base*10H ) + Offset Value. why is it so?. So 8086 can address the locations ranging between 00000 H to FFFFF H. Hardware interrupt is caused by any peripheral device by sending a signal through a specified pin to the microprocessor. The address-object transfers - load effective address and load pointer - are an 8086 facility not present in the 8080. Exceptions and Interrupts. But with the clever use of segmentation, the address space can be expanded to 1 Megabyte. Intel 80386 - A 32-bit Microprocessor with Memory Paging Facility: (8086/8088 to 80386) are upward compatible. Advanced Microprocessors and. Find the physical address in the interrupt vector table associated with Physical Address: 00048H ( 48 through 4BH are set aside for CS & IP) b) 8 - A free PowerPoint PPT presentation (displayed as a Flash slide show) on PowerShow. To locate any adress in the memory bank, it needs the Physical address of that memory. Logical Memory Map: 00000H -> FFFFFH (1 MB, 20 bits) 80286. - supercat Aug 8 '18 at 22:36. Explanation: Physical address = segment address*10H + offset address (or) shift the segment address by four bits to its left and then add the offset address. this arrange ment is done in. The 8086 has complete 16-bit architecture - 16-bit internal registers, 16-bit data bus, and 20-bit address bus (1 MB of physical memory). Problems on physical address calculation in 8086 Microprocessor. The memory in the 8086 architecture is 1M. of locations. Advertised as a "source-code compatible" with Intel 8080 and Intel 8085 processors, the 8086 was not object code compatible with them. To calculate a physical address, you take the address (called the logical address) and add it to the segment address. But until that time, if a program tried to use a Segment:Offset pair that exceeded a 20-bit Absolute address (1MiB), the CPU would truncate the highest bit (an 8086/8088 CPU has only 20 address lines), effectively mapping any value over FFFFFh (1,048,575) to an address within the first Segment. Location of segments • Segment 0 starts at address 0000:0000=00000h and ends at • • •. It belongs to a specific block of memory. This value must be offset from (added to) the segment base address in CS to produce the required 20-bit physical address. El-Sousy Example:. 8086 EMULATION • When running multiple virtual-8086-mode tasks. Address lines define how much memory the processor can access. And an 8086 microprocessor is able to perform these operations with 16-bit data in one cycle. How to calculate Physical Address: Logical Address = Segment : Offset … The 16-bit segment, 16-bit offset Physical Address (20-bit address)= Segment * 10h + Offset Where Memory Segments and Offsets […]. physical address calculation in 8086 microprocessor with example. The 8086 is a 16-bit processor, with 16-bit registers and hence the address space which can be accessed is 2 16 bits (i. Protected mode offered memory protection , and more crucially , it offered address translation. In computing, a physical address (also real address, or binary address), is a memory address that is represented in the form of a binary number on the address bus circuitry in order to enable the data bus to access a particular storage cell of main memory, or a register of memory mapped I/O device. • It can support upto 64K I/O ports. • It has multiplexed address and data bus AD0- AD15 and A16 - A19. The 8086 can read a 16-bit word at an even address in one operation and at an odd address in two operations. When emulating the 8086 address-wraparound that occurs at 1 MByte. Location of segments • Segment 0 starts at address 0000:0000=00000h and ends at • • •. However, its registers and memory locations which contain logical addresses are just 16-bits wide. Address Bus −8085 has 16-bit address bus while 8086 has 20-bit address bus. an odd bank and an even bank. 1 Physical Address Formation The 80386 provides a one Mbyte + 64 Kbyte memory space for an 8086 program. Address line of 8086 microprocessor is 5 nibbles. The lower 16 - bit address lines and 16 - bit data lines are multiplexed (AD0 - AD15). The internal registers of 8086/8088 processors are 16-bit (4 hex digit) wide, whereas the 1MBytemain memory locations require 20bit (5 hex digit) wide physical address (PA). When translating a virtual-address to a physical-address we only deal with the page number. It is a method where the whole memory is segmented (divided) into smaller parts called segments. Each of the registers is 16 bits wide. Provided by Cora Care, LLC Physical Address: 101 Medical Circle, West Columbia SC 29169. The 8086 design could have been extended to a 16MiB address space in a fashion compatible with most existing code, and the 80386 design would have benefited from a mode where the lower portion (maybe 28 bits) of 32-bit segment descriptors would be shifted by an amount controlled by the upper portion. 8086 can access memory with address ranging from 00000 H to FFFFF H. It is developed by Intel. Address Bus − 8085 has 16-bit address bus while 8086 has 20-bit address bus. In computing, a physical address (also real address, or binary address), is a memory address that is represented in the form of a binary number on the address bus circuitry in order to enable the data bus to access a particular storage cell of main memory, or a register of memory mapped I/O device. This is not a physical diagram, only a depiction of the address translation process, specifically for when the CPU has paging enabled. The 8086 addressing scheme is not a virtual one. Physical address: segment * 10H + offset • A4FB*10h + 4872 = A4FB0 + 4872 = A9822h (20-bit address) Physical address maps to several logical addresses • physical address 1256Ah=1256:000Ah=1240:016Ah 29 COE-KFUPM Memory Segmentation - Cont. C-Bus is the internal 20-bit address bus, 16-bit data bus, and possibly control lines of the BIU bus. of Physical lines to carry-out or carry-in are 16 lines some time ALU size also) and 20-bit Address Bus(20-bit Address Bus means : no. Address given to processor(16 bit) - but processor smart - see it adds lower 4bits to the 16 bit to attain 20 bit physical address - to comprehend its smartness they created an oversmart personalty called IP - this oversmart guy stores the 16 bit number that when added to last known instruction address gives us a new instruction address - as BIU is IP's boss so he goes away with. The least significant byte of a word on an 8086 family microprocessor is at the lower address. com - id: 2244f9-Y2FlO 8086 Addressing Modes - To display this on the screen, we need Three. Descriptors and Descriptor Tables. But until that time, if a program tried to use a Segment:Offset pair that exceeded a 20-bit Absolute address (1MiB), the CPU would truncate the highest bit (an 8086/8088 CPU has only 20 address lines), effectively mapping any value over FFFFFh (1,048,575) to an address within the first Segment. Interrupt is the method of creating a temporary halt during program execution and allows peripheral devices to access the microprocessor. Physical address calculation: (16×segment + offset), therefore producing a 20-bit external (or effective or physical). These two buses are represented as ADDR/DATA. Which means it has an memory size of 2^20, i. NMI is a non-maskable interrupt and INTR is a maskable interrupt having lower priority. Explanation: Physical address = segment address*10H + offset address (or) shift the segment address by four bits to its left and then add the offset address. To overcome this, segmentation is necessary, there are four types of segment registers i. The meaning of ALE is address latch enable. Since the logical address space consists of 8 = 2 3 pages, the logical addresses must be 10+3 = 13 bits. NMI and INTR. Address given to processor(16 bit) - but processor smart - see it adds lower 4bits to the 16 bit to attain 20 bit physical address - to comprehend its smartness they created an oversmart personalty called IP - this oversmart guy stores the 16 bit number that when added to last known instruction address gives us a new instruction address - as BIU is IP's boss so he goes away with. Intel 8086 microprocessor is a first member of x86 family of processors. 8086 has a 20 bit address bus. Low speed of execution Low memory addressing capability Limited number of general purpose registers Less powerful instruction set. Address Generation Circuit-The BIU has a Physical Address Generation Circuit. The physical address - is the 20-bit address that is actually put on the address pins of the 8086 microprocessor and decoded by memory interfacing circuitry (00000H - FFFFFH) 2. The four segment registers actually contain the upper 16 bits of the starting addresses of the four memory segments of 64 KB each with which the 8086 is working at that instant of time. • The physical address is calculated as • DS * 10H + 4321 • Assume DS = 5000H • ∴PA = 50000 + 4321 = 54321H • ∴CL ← [54321H] 5. The 8086 has two hardware interrupt pins, i. We have also seen how the 8086 accesses the stack using SS and SP. It is a 20-bit address. Offset, index registers, addressing mode, etc. Pin address. – supercat Aug 8 '18 at 22:36. Physical memory: memory as viewed by the hardware designer. • It has multiplexed address and data bus AD0- AD15 and A16 - A19. same 16 lines are used for both address and data transfer operations (named AD0 to AD15). The 8086 design could have been extended to a 16MiB address space in a fashion compatible with most existing code, and the 80386 design would have benefited from a mode where the lower portion (maybe 28 bits) of 32-bit segment descriptors would be shifted by an amount controlled by the upper portion. the odd bank contains odd numbered mem. 1 Questions & Answers Place. Address Bus − 8085 has 16-bit address bus while 8086 has 20-bit address bus. Offset, index registers, addressing mode, etc. The logic behind this is to save number of pins. Intel 8086 has 20 lines address bus. It is also known as the offset address or the effective address. the even bank contains only even numbered mem. This corresponds to the 64K-byte length of the segment. It generates the 20 bit physical address using Segment and Offset addresses using the formula: Physical Address = Segment Address x 10H + Offset Address; 6 Byte Pre-fetch Queue-It is a 6 byte first in first out (FIFO) RAM used to implement pipelining. 8088/8086 Effective Address (EA) Calculation Description Clock Cycles Displacement 6 Base or Index (BX,BP,SI,DI) 5 Displacement+(Base or Index) 9 Base+Index (BP+DI,BX+SI) 7 Base+Index (BP+SI,BX+DI) 8 Base+Index+Displacement (BP+DI,BX+SI) 11 Base+Index+Displacement (BP+SI+disp,BX+DI+disp) 12 - add 4 cycles for word operands at odd addresses - add 2 cycles for segment override - 80188/80186. half of the data bus (bits 8-15). However, it can handle 8-bit data as well. These objective type 8086 Microprocessor Questions are very important for campus placement test and job. •Thus the physical address of the logical address A4FB:4872 8086 MICROPROCESSOR. Physical Memory 00000 64Kb Data Segment Extra Segment 64Kb Stack Segment The memory in an 8086/88 based system is organized as segmented memory. 8086 CPU is divided into 2 independent functional parts to speed up the processing namely BIU (Bus interface unit) & EU (execution unit). For example, if you wanted to calculate the physical address which relates to logical address "1356" in the stack segment - you would also need to know what value is in the SS register, lets assume "2345":. Operating frequency= 5 MHz. The 8086 is a 16-bit processor, with 16-bit registers and hence the address space which can be accessed is 2 16 bits (i. The term "16-bit" means that its arithmetic logic unit, internal registers, and most of its instructions are designed to work 16-bit binary words. With 20 address lines, the memory that can be addressed is 2 power20 bytes. This address is formed by adding an appended 16 bit segment address and a 16 bit offset address. Address Generation Circuit-The BIU has a Physical Address Generation Circuit. The physical address is then 20bit. As you mentioned 8086 processor i'm explaining with reference to 8086: 8086 is 16-bit processor(16-bit Data Bus means: no. It has 16-bit data bus and 20-bit address bus. Virtual address translation refers to the process of finding out which physical page maps to which virtual page. 3 • 8086 is designed to operate in two modes, Minimum and Maximum. two buses of 8086 are address bus and data bus. To generate this 20 bit physical address from 2 sixteen bit registers, the following procedure is adopted. It is the highest data carrying capacity of 8086. The original 8086 only had registers that were 16 bits in size, effectively allowing to store one value of the range [0 - (2 16 - 1)] (or simpler: it could address up to 65536 different bytes, or 64 kibibytes) - but the address bus (the connection to the memory controller, which receives addresses, then loads the content from the given address. Bus Interface Unit (BIU) Ø In 8086 complete 1MB memory is divided into 16 logical segments. Every memory reference on the 8086 will use one of the segment registers (i. It is the highest data carrying capacity of 8086. 8086 physical memory the total memory (1mb) of 8086 is arranged in two banks. Aaradhana A. LOGICAL AND PHYSICAL ADDRESS. In this article, we are going to solve some problems on calculating the physical address (also known as effective address) of 20 bits using the different segment registers and their respective offsets. Krishna Kumar. Note that the 80386 and above have a far greater selection of segment offset address combinations than do the 8086 through the 80286 microprocessors. 3G physical arrangements that you see have to do with needing to keep some of the lower 4G open for PCI devices, VGA buffers, classic <1M 8086 crap, etc. 16-Bit Protected Mode. , 1 MB address in the memory. With 20 address lines, the memory that can be addressed is 220 bytes. Microprocessor-based System Design Ricardo Gutierrez-Osuna Wright State University 6 Partial address decoding g Let's assume the same microprocessor with 10 address lines (1KB memory) n However, this time we wish to implement only 512 bytes of memory n We still must use 128-byte memory chips n Physical memory must be placed on the upper half of the memory map. It has data and address bus of 32-bit each. 8086 segmentation offers no memory protection, and segments could start on any 16 byte boundary - there was no restriction to 64K boundaries at all; and a given physical address can have many segment:offset representations. Q:-10 Write the name of one signal of 8086 which does not have any importance for 8088 and why? Q:-11 (i) Explain the memory segmentation and write its advantages. Hardware interrupt is caused by any peripheral device by sending a signal through a specified pin to the microprocessor. Physical address is obtained by shifting the segment address 4 bits to left adding the offset address. ALE (Address Latch Enable): On both the 8086 and 8088 processors the address and data buses are multiplexed. Hence, the physical memory space of the 8086 is 1Mb (1 Mega-byte). of Physical lines to carry-out the address are 20) these lines are nothing but 8086-pins. On these lines the CPU sends out the address of the memory location that is to be written to or read from. The following image shows the types of interrupts we have in a 8086 microprocessor −. So the maximum value of address that can be addressed by 8086 is 2^20 = 1MB. In 8086 we have base registers and index registers. The port address is sent out directly from the 8086 on lines AD0-AD15, and 0's are output on lines A16-A19. It's 20 bit address bus can address 1MB of memory, it segments it into 4 64kB segments. 8086 has a concept of Memory Segmentation. So it can access 1 MB memory (220*8=1 MB or 16*64 KB). The 8086 can read a 16-bit word at an even address in one operation and at an odd address in either case. Favourite answer. The Intel 8088, released July 1, 1979, is a slightly modified chip with an external 8-bit data bus (allowing the use of cheaper and fewer supporting ICs), and is notable as the processor used in the original IBM PC design. 8086 provides the programmer with 14 internal registers, each 16 bits or 2 Bytes wide. Definition: 8086 is a 16-bit microprocessor and was designed in 1978 by Intel. 8086 microprocessor from Douglas Hall, Microprocessor and Interfacing, TMH. Ø While addressing any location in the memory bank, the Physical address is calculated from two parts, the first part is Segment address, and the second is Offset. It is a 16-bit Microprocessor having 20 address lines and16 data lines that provides up to 1MB storage. We look forward to being of service - always. When emulating the 8086 address-wraparound that occurs at 1 MByte. it is known as upper bank. , DS, ES, SS, CS, or SS) as the segment combined with an offset (usually given in the instruction) to determine the physical address being referenced. The basic memory word size of the memories used in the 8086 system is 8-bit or 1-byte (i. The Intel 8086 is a 16-bit microprocessor intended to be used as the CPU in a microcomputer. However, it can handle 8-bit data as well. Hence 8086 uses memory segmentation. Deshmukh, SKNCOE, Comp. How to calculate Physical Address: Logical Address = Segment : Offset … The 16-bit segment, 16-bit offset Physical Address (20-bit address)= Segment * 10h + Offset Where Memory Segments and Offsets […]. The number of address lines in 8086 is 20, 8086 BIU will send 20bit address, so as to access one of the 1MB memory locations. This may map directly onto the physical RAM (in which case, if there is less than 4 GB of RAM, some address space is unused), or paging may be used to arbitrarily translate between virtual addresses and physical addresses. The four segment registers actually contain the upper 16 bits of the starting addresses of the four memory segments of 64 KB each with which the 8086 is working at that instant of time. Memory Segmentation. 8086 addresses via its A0-A19 address lines. Physical addresses refer to actual RAM addresses, as in their is no virtual address translation and usually no memory protection either. 80386 Microprocessor is a 32-bit processor that holds the ability to carry out 32-bit operation in one cycle. The CPU (or other device) can use the code to access the corresponding memory location. It is a 16-bit Microprocessor having 20 address lines and16 data lines that provides up to 1MB storage. Sub: 8086 VIVA QUESTIONS Explain how to generate the physical address w. The 8086 design could have been extended to a 16MiB address space in a fashion compatible with most existing code, and the 80386 design would have benefited from a mode where the lower portion (maybe 28 bits) of 32-bit segment descriptors would be shifted by an amount controlled by the upper portion. It generates the 20 bit physical address using Segment and Offset addresses using the formula: Physical Address = Segment Address x 10H + Offset Address; 6 Byte Pre-fetch Queue-It is a 6 byte first in first out (FIFO) RAM used to implement pipelining. Using an IDE. My question is if the segment register and the offset value both are FFFFH and FFFFH then the result would be more than FFFFH i. Q:-10 Write the name of one signal of 8086 which does not have any importance for 8088 and why? Q:-11 (i) Explain the memory segmentation and write its advantages. 8086 works only with four 64KB segments within the whole 1MB memory. 16-Bit Protected Mode. Each byte has a specific address. There are four 16-bit segment registers, viz. The offset part of the virtual address is added to the base address to produce the actual physical address. However, its registers and memory locations which contain logical addresses are just 16-bits wide. Instruction Set. Submitted by Monika Sharma, on July 11,. NMI and INTR. A segment is just an area in memory. This 1 MB memory is divided into 16 Segment memories. Thus, 10FFEFh was mapped to FFEFh. Microprocessor 8086/8088 Upon completion of this chapter, you will be able to: Explain the operation of each data -addressing mode. The number of address lines in 8086 is 20, 8086 BIU will send 20bit address, so as to access one of the 1MB memory locations. It has data and address bus of 32-bit each. Segment relocation is performed as in the 8086: the 16-bit value in a segment selector is shifted left by four bits to form the base address of a segment. In this article, we will also learn that how the 8086 microprocessor is capable of handling up to 16 bits of data at a time even though each memory location in it is byte-addressable. A physical address is generated in an 8086/8088 by adding the desired offset to the value of the appropriate segment register shifted left by 4 bits. A segment is just an area in memory. BE HAPPY - - - JAAAY HANUMAN ( Collect!on of MUS!C , Action Scenes , News , Tragedy Songs , Devotional Songs , Message Oriented Topics , Motivational & Inspirational Speeches , Pathetic Songs , Patriotic Songs , Life Stories …. We use cookies to make interactions with our website easy and meaningful, to better understand the use of our services, and to tailor advertising. 8086 Microprocessor- bus interface unit ,Execution unit A + A ; A- The BIU also contains a dedicated adder which is used to generate the 20bit physical address that is output on the address bus. - The physical address or the real address is formed by combining the offset and base segment addresses. Problems on physical address calculation in 8086 Microprocessor In this article, we are going to solve some problems on calculating the physical address (also known as effective address) of 20 bits using the different segment registers and their respective offsets. World's Most Famous Hacker Kevin Mitnick & KnowBe4's Stu Sjouwerman Opening Keynote - Duration: 36:30. The processor uses CS segment. •It can support up to 64K I/O ports. This corresponds to the 64K-byte length of the segment. As you noted, the physical page is determined by the translation table, indexed using the logical (virtual) address. we should conduct business and plan to update this message as soon as we can. During resetting, all internal register contents are set to 0000 H, but CS is set to F000 H and IP to FFF0 H. Intel 8086 has 20 lines address bus. The lower 16 - bit address lines and 16 - bit data lines are multiplexed (AD0 - AD15). The 8086 has two parts, the Bus Interface Unit (BIU) and the Execution Unit. d) Physical memory organization: The 8086's 1Mbyte memory address space is divided in to two independent 512Kbyte banks: the low (even) bank and the high (odd) bank. Ø While addressing any location in the memory bank, the Physical address is calculated from two parts, the first part is Segment address, and the second is Offset. Segmentation was introduced on the Intel 8086 in 1978 as a way to allow programs to address more than 64 KB (65,536 bytes) of memory. It has 16-bit data bus and 20-bit address bus. Note that the 8086 contains 20 address pins, so the physical address size is 20. The lower 16 bits of addresses are multiplexed on the data bus. Protected Virtual Mode: 16 MB (24-bit addresses) up to 16,384 segments @ 64 kB per segment; Virtual memory machine:. ¾the memory is organized as a set of segments ¾Each segment of memory is a linear contiguous sequence of up to 64K bytes In this segmented memory organization, we have to specify two components to. The microprocessor responds to that interrupt with an ISR (Interrupt Service Routine), which is a short program to instruct the microprocessor on how to handle the interrupt. my question is when we encounter the problem of calculating the physical address from the logical, a 4bit hexadecimal segment address is given. With 20-bit address the processor can generate 220 = 1 Mega address. A 20-bit external address bus provides a 1 MB physical address space (2 20 = 1,048,576). The memory in the 8086 architecture is 1M. of Physical lines to carry-out or carry-in are 16 lines some time ALU size also) and 20-bit Address Bus(20-bit Address Bus means : no. This value must be offset from (added to) the segment base address in CS to produce the required 20-bit physical address. The number of address lines determines. The 8086 (also called iAPX 86) is a 16-bit microprocessor chip designed by Intel between early 1976 and June 8, 1978, when it was released. Microprocessor 8086 is the first in its family to get more popular than other microprocessor. This 1MB memory is divided into 16 logical segments, each with a memory of 64KB. ALE (Address Latch Enable): On both the 8086 and 8088 processors the address and data buses are multiplexed. It is the highest data carrying capacity of 8086. - The physical address or the real address is formed by combining the offset and base segment addresses. The 8086 was able to address one MByte of physical memory and its external address bus was 20 bit wide (the first 16 multiplexed with the data bus). It is a method where the whole memory is segmented (divided) into smaller parts called segments. ) reside in the low bank, and those with odd addresses (0000116, 0000316, etc. Instructions That Are Used To Transfer Data/ PPT. Submitted by Monika Sharma, on July 11,. , the code segment (CS), the stack segment (SS), the extra segment (ES), and the data segment (DS). The lower 16 - bit address lines and 16 - bit data lines are multiplexed (AD0 - AD15). The least significant byte of a word on an 8086 family microprocessor is at the lower address. B-bus has no true name but the function of the adder ALU is to add the shifted 16-bits (Starting Address of 64 Kbyte segment) CS (Code Segment) to the 16-bits IP (Instruction Pointer - Offset into CS for next instruction) to get the 20-bit Physical. All internal registers, as well as internal and external data buses, are 16 bits wide, which firmly established the "16-bit microprocessor" identity of the 8086. 8086 has a concept of Memory Segmentation. With 20 address lines, the memory that can be addressed is 2 power20 bytes. It has data and address bus of 32-bit each. For example, in PC-DOS, there were a number of DOS variables stored at the 1K mark, which could be. Addressing Modes • When the 8088 executes an instruction, it performs the specified function on data • These data, called operands, – May be a part of the instruction – May reside in one of the internal registers of the microprocessor – May be stored at an address in memory • Register Addressing Mode – MOV AX, BX – MOV ES,AX. 8086 segmentation offers no memory protection, and segments could start on any 16 byte boundary - there was no restriction to 64K boundaries at all; and a given physical address can have many segment:offset representations. Ø While addressing any location in the memory bank, the Physical address is calculated from two parts, the first part is Segment address, and the second is Offset. 2power20= 1,048,576 bytes (1 MB). , DS, ES, SS, CS, or SS) as the segment combined with an offset (usually given in the instruction) to determine the physical address being referenced. Apr 18, 2020 - Instruction Set Of 8086 Computer Science Engineering (CSE) Notes | EduRev is made by best teachers of Computer Science Engineering (CSE). d) Physical memory organization: The 8086’s 1Mbyte memory address space is divided in to two independent 512Kbyte banks: the low (even) bank and the high (odd) bank. Protected Virtual Mode: 16 MB (24-bit addresses) up to 16,384 segments @ 64 kB per segment; Virtual memory machine:. Each byte has a specific address. On these lines the CPU sends out the address of the memory location that is to be written to or read from. ALE (Address Latch Enable): On both the 8086 and 8088 processors the address and data buses are multiplexed. There are some other differences between the logical and physical address. Physical address of 8086 is 20 bit wide.