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  2. Addressing mode - Wikipedia

    en.wikipedia.org/wiki/Addressing_mode

    The PC-relative addressing mode can be used to load a register with a value stored in program memory a short distance away from the current instruction. It can be seen as a special case of the "base plus offset" addressing mode, one that selects the program counter (PC) as the "base register".

  3. Simplified Instructional Computer - Wikipedia

    en.wikipedia.org/wiki/Simplified_Instructional...

    The Simplified Instructional Computer (abbreviated SIC) is a hypothetical computer system introduced in System Software: An Introduction to Systems Programming, by Leland Beck. Due to the fact that most modern microprocessors include subtle, complex functions for the purposes of efficiency, it can be difficult to learn systems programming using ...

  4. Orthogonal instruction set - Wikipedia

    en.wikipedia.org/wiki/Orthogonal_instruction_set

    In computer engineering, an orthogonal instruction set is an instruction set architecture where all instruction types can use all addressing modes.It is "orthogonal" in the sense that the instruction type and the addressing mode may vary independently.

  5. ModR/M - Wikipedia

    en.wikipedia.org/wiki/ModR/M

    The "mod" field specifies the addressing mode for the register/memory ("r/m") operand. If the "mod" field is 11 2, the "r/m" field encodes a register in the same manner as the "reg" field. However, if the "mod" field is anything else (00 2, 01 2, or 10 2), the "r/m" field specifies an addressing mode. The interpretation of these five bits ...

  6. Complex instruction set computer - Wikipedia

    en.wikipedia.org/wiki/Complex_instruction_set...

    A complex instruction set computer (CISC / ˈ s ɪ s k /) is a computer architecture in which single instructions can execute several low-level operations (such as a load from memory, an arithmetic operation, and a memory store) or are capable of multi-step operations or addressing modes within single instructions.

  7. z/Architecture - Wikipedia

    en.wikipedia.org/wiki/Z/Architecture

    In addition to the two addressing modes supported by S/370-XA and ESA, a/Architecture has an extended addressing mode with 64-bit virtual addresses. The addressing mode is controlled by the EA (bit 31) and BA (bit 32) bits in the PSW. The valid combinations are 00 24-bit addressing; 01 31-bit addressing; 11 64-bit addressing

  8. System Management Mode - Wikipedia

    en.wikipedia.org/wiki/System_Management_Mode

    The processor executes the SMM code in a separate address space (SMRAM) that has to be made inaccessible to other operating modes of the CPU by the firmware. [7] System Management Mode can address up to 4 GB memory as huge real mode. In x86-64 processors, SMM can address >4 GB memory as real address mode. [8]

  9. Minimal instruction set computer - Wikipedia

    en.wikipedia.org/wiki/Minimal_instruction_set...

    Minimal instruction set computer (MISC) is a central processing unit (CPU) architecture, usually in the form of a microprocessor, with a very small number of basic operations and corresponding opcodes, together forming an instruction set. Such sets are commonly stack-based rather than register-based to reduce the size of operand specifiers.