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x86 Interrupts and system calls

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linux-howto

http://www.unix.com – I recently went through Understanding the linux kernel, to get an idea of how system calls and interrupts function in an x86 based machine. However, the level of detail has left me slightly confused. Here's what I understand. System call process: User mode: User code calls a library function -> library function involves making a system call -> the int 0x80 instruction is executed causing transfer to kernel mode Kernel mode: Dispatch table is looked up for validity of the system call no. passed via eax register and if valid, backs up remaining structures onto kernel mode stack->sy (HowTos)