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The x86 instruction set refers to the set of instructions that x86-compatible microprocessors support. The instructions are usually part of an executable program, often stored as a computer file and executed on the processor. The x86 instruction set has been extended several times, introducing wider registers and datatypes as well as new ...
A listing of the opcodes/instructions supported by the 72291 is available. [34] BRKEM imm8: 0F FF ib: Break to 8080 emulation mode. Jump to an address picked from the IVT (Interrupt Vector Table) using the imm8 argument, similar to the 8086 INT instruction, but start executing as Intel 8080 code rather than x86 code. V20, V30, V40, V50 [32 ...
x86 assembly language includes instructions for a stack-based floating-point unit (FPU). The FPU was an optional separate coprocessor for the 8086 through the 80386, it was an on-chip option for the 80486 series, and it is a standard feature in every Intel x86 CPU since the 80486, starting with the Pentium.
Opcodes in x86 are generally one-byte, though two-byte instructions and prefixes exist. ModR/M is a byte that, if required, follows the opcode and specifies zero, one, or two operands for the instruction.
The x86 instruction set has several times been extended with SIMD (Single instruction, multiple data) instruction set extensions.These extensions, starting from the MMX instruction set extension introduced with Pentium MMX in 1997, typically define sets of wide registers and instructions that subdivide these registers into fixed-size lanes and perform a computation for each lane in parallel.
Previously, those opcodes were individual INC and DEC instructions for the eight standard processor registers; x86-64 code must use ModR/M INC and DEC instructions. [ 6 ] Legacy SIMD instructions with a VEX prefix added are equivalent to the same instructions without VEX prefix with the following differences:
Instruction set extensions that have been added to the x86 instruction set in order to support hardware virtualization.These extensions provide instructions for entering and leaving a virtualized execution context and for loading virtual-machine control structures (VMCSs), which hold the state of the guest and host, along with fields which control processor behavior within the virtual machine.
Pages in category "x86 instructions" The following 53 pages are in this category, out of 53 total. ... INT (x86 instruction) Intel ADX; Intel BCD opcodes; Intel MPX;