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Below is the full 8086/8088 instruction set of Intel (81 instructions total). [2] These instructions are also available in 32-bit mode, in which they operate on 32-bit registers (eax, ebx, etc.) and values instead of their 16-bit (ax, bx, etc.) counterparts.
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.
Whereas the 8086 was a 16-bit microprocessor, it used the same microarchitecture as Intel's 8-bit microprocessors (8008, 8080, and 8085). This allowed assembly language programs written in 8-bit to seamlessly migrate. [7] New instructions and features — such as signed integers, base+offset addressing, and self-repeating operations — were added.
x86 (also known as 80x86 [3] or the 8086 family [4]) is a family of complex instruction set computer (CISC) instruction set architectures [a] initially developed by Intel, based on the 8086 microprocessor and its 8-bit-external-bus variant, the 8088.
Assembly language for the 8086 family provides the mnemonic MOV (an abbreviation of move) for instructions such as this, so the machine code above can be written as follows in assembly language, complete with an explanatory comment if required, after the semicolon. This is much easier to read and to remember.
In the x86 assembly language, the JMP instruction performs an unconditional jump. Such an instruction transfers the flow of execution by changing the program counter.There are a number of different opcodes that perform a jump; depending on whether the processor is in real mode or protected mode, and an override instruction is used, the instructions may take 16-bit, 32-bit, or segment:offset ...
Pointer formats are known as near, far, or huge.. Near pointers are 16-bit offsets within the reference segment, i.e. DS for data and CS for code. They are the fastest pointers, but are limited to point to 64 KB of memory (to the associated segment of the data type).
INT is an assembly language instruction for x86 processors that generates a software interrupt. It takes the interrupt number formatted as a byte value. [1] When written in assembly language, the instruction is written like this: INT X. where X is the software interrupt that should be generated (0-255).