Aspect of the instruction set architecture of CPUs
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Addressing modes are an aspect of the instruction set architecture in most central processing unit (CPU) designs. The various addressing modes that are defined in a given instruction set architecture define how the machine language instructions in that architecture identify the operand(s) of each instruction. 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. For a related concept see orthogonal instruction set which deals with the ability of any instruction to use any addressing mode.
Addressingmodes are an aspect of the instruction set architecture in most central processing unit (CPU) designs. The various addressingmodes that are...
Real mode, also called real addressmode, is an operating mode of all x86-compatible CPUs. The mode gets its name from the fact that addresses in real...
in 64-bit mode, which is one of the two modes only available in long mode. The addressingmodes were not dramatically changed from 32-bit mode, except that...
in MMX) registers. The x86 processor also includes complex addressingmodes for addressing memory with an immediate offset, a register, a register with...
In computing, protected mode, also called protected virtual addressmode, is an operational mode of x86-compatible central processing units (CPUs). It...
involves the jump instruction when using indirect addressing. In this addressingmode, the target address of the JMP instruction is fetched from memory,...
bits: n: Indirect addressing flag i: Immediate addressing flag x: Indexed addressing flag b: Base address-relative flag p: Program counter-relative flag...
memory addressing paradigm in which "memory appears to the program as a single contiguous address space." The CPU can directly (and linearly) address all...
to address the main memory. Such devices, therefore, also need to have a knowledge of physical addresses. Address constant AddressingmodeAddress space...
sequence called inter-mode.[citation needed] Mode S equipped aircraft are assigned a unique ICAO 24-bit address or (informally) Mode-S "hex code" upon national...
56 instructions with (possibly) multiple addressingmodes. Depending on the instruction and addressingmode, the opcode may require zero, one or two additional...
256 local addresses. The leading bit sequence 111 designated an at-the-time unspecified addressingmode ("escape to extended addressingmode"), which was...
access to the entire memory. Contrary to its name, it is not a separate addressingmode that the x86 processors can operate in. It is used in the 80286 and...
addressingmode. The base-plus-index and scale-plus-index forms of 32-bit addressing (encoded with r/m = 100 and mod ≠ 11) require another addressing...
Direct page addressing uses an 8-bit address, which results in faster access than when a 16- or 24-bit address is used. Also, some addressingmodes that offer...
another specifies the addressingmode. An orthogonal instruction set uniquely encodes all combinations of registers and addressingmodes. In telecommunications...
same MAC address. The IEEE 802 MAC address originally comes from the Xerox Network Systems Ethernet addressing scheme. This 48-bit address space contains...
instruction types can use all addressingmodes. It is "orthogonal" in the sense that the instruction type and the addressingmode vary independently. An orthogonal...
selective reflection. Each sub-pixel of a display device must be selected (addressed) in order to be energized in a controlled way. Display device ISO 13406-2...
performed by control registers include interrupt control, switching the addressingmode, paging control, and coprocessor control. The early CPU lacked dedicated...
Indicating indirect addressing used separate opcodes, as opposed to using the addressing indication bits. When used, the address was constructed as normal...
destination addressingmode and register. If field I = 0, designated register contains the address of the operand, the equivalent of addressingmode (Rn). If...
instances (XA/370), the instruction address was 31 bits plus a mode bit (24 bit addressingmode if zero; 31 bit addressingmode if one) for a total of 32 bits...
64-bit mode of x86-64 CPU, or the Physical Address Extension (PAE), a 36-bit addressingmode. In such a case, a device using DMA with a 32-bit address bus...
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