DOS INTERRPUTS 5.1 Introduction The DOS (Disk Operating System) provides a large number of procedures to access devices, files and memory. These procedures can be called in any user program using software interrupts “INT n” instruction. The DOS interrupt INT 21H provides a large number of services. A function code has been allocated to each […]
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Posts by Farahat
Module3 8086 Microprocessor and Peripherals part2 .
ASSUME CS: PROGRAM, DS: PROGRAM, SS: PROGRAM. LABEL: Label The Label directive is used to assign a name to the current content of the location counter. At the start of the assembly process, the assembler initialises a location counter to keep rack of memory locations assigned to the program. As the program assembly proceeds, the […]
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Module4 8086 Microprocessor and Peripherals part3 .
4.3.1 Interrupt Programming Program 4.3 Write a program to a create a file RESULT and store in it 500H bytes from the memory block starting at 1000:1000, if either an interrupt occurs at INTR pin with Type 0AH or an instruction equivalent to the above interrupt is executed. ASSUME CS:CODE, DS:DATA DATA SEGMENT FILENAME DB […]
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Module4 8086 Microprocessor and Peripherals part2 .
4.2.1 Programming for Stack Program 4.1 WAP to calculate squares of BCD numbers 0 to 9 and store them from 2000h offset onwards in the current data segment. The numbers and their squares are in the BCD format. Write a subroutine for the calculation of the square of a number. ASSUME CS:CODE,DS:DATA,SS:STACK DATA SEGMENT ORG […]
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Module4 8086 Microprocessor and Peripherals part1 .
4.1 LINKING AND RELOCATION Figure 4.1 Creation and execution of a program The DOS linking program links the different object modules of a source program and function library routines to generate an integrated executable code of the source program. The main input to the linker is the .OBJ file that contains the object modules of […]
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Module3 8086 Microprocessor and Peripherals part1 .
ASSEMBLER DIRECTIVES AND OPERATORS The main advantage of machine language programming is that the memory control is directly in the hands of the programmer, so that, he may be able to manage the memory of the system more efficiently. On the other hand, the disadvantages are more prominent. The programming, coding and resource management techniques […]
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Module2 8086 Microprocessor and Peripherals part3.
Data Transfer Instructions : The MOV instruction is used to transfer a byte or a word of data from a source operand to a destination operand. These operands can be internal registers of the 8086 and storage locations in memory. MOV instruction cannot transfer data directly between a source and a destination that both reside […]
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Module2 8086 Microprocessor and Peripherals part2 .
String Manipulation Instructions A series of data byte or word available in memory at consecutive locations, to be referred as Byte String or Word String. A String of characters may be located in consecutive memory locations, where each character may be represented by its ASCII equivalent. The 8086 supports a set of more powerful instructions […]
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Module2 8086 Microprocessor and Peripherals part1 .
2.1 Read Write Timing Diagram General Bus Operation The 8086 has a combined address and data bus commonly referred as a time multiplexed address and data bus. The main reason behind multiplexing address and data over the same pins is the maximum utilization of processor pins and it facilitates the use of 40 pin standard […]
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Module1 8086 Microprocessor and Peripherals part2 .
MINIMUM MODE 8086 SYSTEM AND TIMINGS In a minimum mode 8086 system, the microprocessor 8086 is operated in minimum mode by strapping its MN/MX* pin to logic1. In this mode, all the control signals are given out by the microprocessor chip itself. There is a single microprocessor in the minimum mode system. The remaining components […]
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