Code Memory Read-Only Data Moves Data moves between RAM locations and 8051 registers are made by using MOV and MOVX opcodes. The data is usually of a temporary or "scratch pad" nature and disappears when the system is powered down. There are times when access to a preprogrammed mass of data is needed, such as […]
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Posts by Farahat
Indirect Addressing Mode
Indirect Addressing Mode For all the addressing modes covered to this point, the source or destination of the data is an absolute number or a name. Inspection of the opcode reveals exactly what are the addresses of the destination and source. For example, the opcode MOV A,R7 says that the A register will get a […]
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Direct Addressing Mode
Direct Addressing Mode All 128 bytes of internal RAM and the SFRs may be addressed directly using the single byte address assigned to each RAM location and each special-function register. Internal RAM uses addresses from 00 to 7Fh to address each byte. The SFR addresses exist from 80h to FFh at the following locations: SFR […]
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Moving Data
Moving Data Outline: o Introduction o Addressing Modes o External Data Moves o PUSH and POP Opcodes o Data Exchanges o Example Programs o Summary Introduction A computer typically spends more time moving data from one location to another than it spends on any other operation. It is not surprising, therefore, to find that more […]
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ASSIGNMENTS on Software Development Systems and Assemblers
ASSIGNMENTS Check the appropriate answer in 1-10. 1. The process of accessing information on a floppy disk is a. random. b. serial. c. semirandom. 2. The operating system of a computer is defined as hardware that operates the floppy disk. a program that manages files on the disk. a group of programs that manages and […]
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SUMMARY of Software Development Systems and Assemblers
SUMMARY A software development system and an assembler are essential tools for writing, assembling, testing, and debugging large assembly language programs. A disk-based microcomputer, its operating system, and assembler programs can serve as a development system. All the operations of the computer are managed and directed by the operating system of the computer. The Assembler […]
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WRITING PROGRAMS USING A CROSS-ASSEMBLER
7.4 WRITING PROGRAMS USING A CROSS-ASSEMBLER This section describes a commercially available Z80 cross-assembler and the process of assembling a program. The description in the following sections is equally applicable to both assemblers and cross-assemblers; therefore, the term assembler should be interpreted as the representation of both. The assembly process is illustrated with a simple […]
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ASSEMBLERS
7.3 ASSEMBLERS The assembler (or the cross-assembler), as defined before, is a program that translates assembly language mnemonics or source code into binary executable code. Here, we are using the term assembler to include all the utility programs (such as Assembler and Linker) necessary for the assembly process. This translation process requires that the source […]
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OPERATING SYSTEMS
7.2 OPERATING SYSTEMS The operating system of a computer is a group of programs that manages or oversees all the operations of the computer. The computer transfers information constantly among peripherals such as a floppy disk, printer, keyboard, and video monitor. It also stores user programs under file names on a disk. (A file is […]
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MICROPROCESSOR-BASED SOFTWARE DEVELOPMENT SYSTEMS
7.1 MICROPROCESSOR-BASED SOFTWARE DEVELOPMENT SYSTEMS A software development system is simply a computer that enables the user to write, modify, debug, and test programs. In a microprocessor-based development system, a microcomputer is used to develop software for a particular microprocessor. Generally, the microcomputer has a large R/W memory (640K bytes or higher), disk storage, and […]
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