Search results
Results from the WOW.Com Content Network
Memory address. In a computer using virtual memory, accessing the location corresponding to a memory address may involve many levels. In computing, a memory address is a reference to a specific memory location used at various levels by software and hardware. [1] Memory addresses are fixed-length sequences of digits conventionally displayed and ...
An addressing mode specifies how to calculate the effective memory address of an operand by using information held in registers and/or constants contained within a machine instruction or elsewhere. In computer programming, addressing modes are primarily of interest to those who write in assembly languages and to compiler writers.
e. Real mode, also called real address mode, is an operating mode of all x86 -compatible CPUs. The mode gets its name from the fact that addresses in real mode always correspond to real locations in memory. Real mode is characterized by a 20- bit segmented memory address space (giving 1 MB of addressable memory) and unlimited direct software ...
x86 memory segmentation. The Intel x86 computer instruction set architecture has supported memory segmentation since the original Intel 8086 in 1978. It allows programs to address more than 64 KB (65,536 bytes) of memory, the limit in earlier 80xx processors. In 1982, the Intel 80286 added support for virtual memory and memory protection; the ...
Direct memory access (DMA) is a feature of computer systems that allows certain hardware subsystems to access main system memory independently of the central processing unit (CPU). [ 1 ] Without DMA, when the CPU is using programmed input/output , it is typically fully occupied for the entire duration of the read or write operation, and is thus ...
Diagram of relationship between the virtual and physical address spaces. 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 step evaluates which type of operation is to be performed, and if it is a memory operation, the computer determines the effective memory address to be used in the following Execute stage. There are various possible ways that a computer architecture can specify for determining the address, usually called the addressing modes.
Flat memory model or linear memory model refers to a memory addressing paradigm in which " memory appears to the program as a single contiguous address space." [1] The CPU can directly (and linearly) address all of the available memory locations without having to resort to any sort of bank switching, memory segmentation or paging schemes.