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Load GDTR (Global Descriptor Table Register) from memory. [b] Yes 0 LIDT m16&32 [a] 0F 01 /3: Load IDTR (Interrupt Descriptor Table Register) from memory. [b] The IDTR controls not just the address/size of the IDT (interrupt Descriptor Table) in protected mode, but the IVT (Interrupt Vector Table) in real mode as well. LMSW r/m16: 0F 01 /6
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).
x86 assembly language is a family of low-level programming languages that are used to produce object code for the x86 class of processors. These languages provide backward compatibility with CPUs dating back to the Intel 8008 microprocessor, introduced in April 1972.
; The 'enter' instruction can also do something similar); sub esp, 12 : 'enter' instruction could do this for us; mov [ebp-4], 3 : or mov [esp+8], 3; mov [ebp-8], 2 : or mov [esp+4], 2; mov [ebp-12], 1 : or mov [esp], 1 push 3 push 2 push 1 call callee; call subroutine 'callee' add esp, 12; remove call arguments from frame add eax, 5; modify ...
Furthermore, on a modern x86 system, BIOS calls can only be performed in Real mode, or Virtual 8086 mode. v8086 is not an option in Long mode. This means that a modern operating system, which operates in Protected mode (32 bit), or Long mode (64 bit), would need to switch into real mode and back to call the BIOS - a hugely expensive operation.
The application program interfaces of IBM's mainframe operating systems is defined as a set of assembly language "macro" instructions, that typically invoke Supervisor Call (SVC) [e.g., on z/OS] or Diagnose (DIAG) [on, e.g., z/VM] instructions to invoke operating system routines. It is possible to use operating system services from programs ...
Machine code is the form in which code that can be directly executed is stored on a computer. It consists of machine language instructions, stored in memory, that perform operations such as moving values in and out of memory locations, arithmetic and Boolean logic, and testing values and, based on the test, either executing the next instruction in memory or executing an instruction at another ...
Ralf Brown's Interrupt List (aka RBIL, x86 Interrupt List, MS-DOS Interrupt List or INTER) is a comprehensive list of interrupts, calls, hooks, interfaces, data structures, CMOS settings, memory and port addresses, as well as processor opcodes for x86 machines from the 1981 IBM PC up to 2000 (including many clones), [1] [2] [nb 1] most of it still applying to IBM PC compatibles today.