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  2. Memory-mapped I/O and port-mapped I/O - Wikipedia

    en.wikipedia.org/wiki/Memory-mapped_I/O_and_port...

    Memory-mapped I/O is preferred in IA-32 and x86-64 based architectures because the instructions that perform port-based I/O are limited to one register: EAX, AX, and AL are the only registers that data can be moved into or out of, and either a byte-sized immediate value in the instruction or a value in register DX determines which port is the source or destination port of the transfer.

  3. Memory map - Wikipedia

    en.wikipedia.org/wiki/Memory_map

    It is the fastest and most flexible cache organization that uses an associative memory. The associative memory stores both the address and content of the memory word. [further explanation needed] In the boot process of some computers, a memory map may be passed on from the firmware to instruct an operating system kernel about memory layout. It ...

  4. PCI configuration space - Wikipedia

    en.wikipedia.org/wiki/PCI_configuration_space

    To address a PCI device, it must be enabled by being mapped into the system's I/O port address space or memory-mapped address space. The system's firmware (e.g. BIOS) or the operating system program the Base Address Registers (commonly called BARs) to inform the device of its resources configuration by writing configuration commands to the PCI ...

  5. Memory address register - Wikipedia

    en.wikipedia.org/wiki/Memory_address_register

    When reading from memory, data addressed by MAR is fed into the MDR (memory data register) and then used by the CPU. When writing to memory, the CPU writes data from MDR to the memory location whose address is stored in MAR. MAR, which is found inside the CPU, goes either to the RAM (random-access memory) or cache.

  6. Direct memory access - Wikipedia

    en.wikipedia.org/wiki/Direct_memory_access

    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 ...

  7. Content-addressable memory - Wikipedia

    en.wikipedia.org/wiki/Content-addressable_memory

    Unlike standard computer memory, random-access memory (RAM), in which the user supplies a memory address and the RAM returns the data word stored at that address, a CAM is designed such that the user supplies a data word and the CAM searches its entire memory to see if that data word is stored anywhere in it. If the data word is found, the CAM ...

  8. Cache placement policies - Wikipedia

    en.wikipedia.org/wiki/Cache_placement_policies

    Address 0x0004 (tag - 0b000_0000, index – 0b0_0001, offset – 0b00) corresponds to block 1 of the memory and maps to the set 1 of the cache. The block occupies a cache line in set 1, determined by the replacement policy for the cache. Address 0x00FF (tag – 0b000_0001, index – 0b1_1111, offset – 0b11) corresponds to block 63 of the ...

  9. Instruction register - Wikipedia

    en.wikipedia.org/wiki/Instruction_register

    Decoding the op-code in the instruction register includes determining the instruction, determining where its operands are in memory, retrieving the operands from memory, allocating processor resources to execute the command (in super scalar processors), etc.