InterruptContext Struct Reference

Preserved interrupt context. More...

#include <handler.h>

Public Attributes
uintptr_t	eax
	scratch register EAX
uintptr_t	ecx
	scratch register ECX
uintptr_t	edx
	scratch register EDX
uintptr_t	error_code
	Error Code.
uintptr_t	ip
	Instruction Pointer (at interrupt)
uintptr_t	cs: 16
	Code segment (in case of a ring switch it is the segment of the user mode)
uintptr_t	__pad0__: 0
	Alignment (due to 16 bit code segment)
uintptr_t	flags
	Status flags register.
uintptr_t	sp
	Stack pointer (at interrupt)
uintptr_t	ss: 16
	Stack segment (in case of a ring switch it is the segment of the user mode)
uintptr_t	__pad1__: 0
	Alignment (due to 16 bit stack segment)

Detailed Description

Preserved interrupt context.

After an interrupt was triggered, the core first saves the basic context (current code- & stack segment, instruction & stack pointer and the status flags register) and looks up the handling function for the vector using the IDT. In StuBS for each vector an own interrupt_entry_VECTOR function (written in assembly in interrupt/handler.asm) was registered during boot by kernel_init(), which all save the scratch registers on the stack before calling the C++ function interrupt_handler(). The high-level handler gets a pointer to the part of the stack which corresponds to the InterruptContext structure as second parameter. After returning from the high-level handler, the previous state is restored from this context (scratch register in assembly and basic context while executing iret) so it can continue transparently at the previous position.

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The documentation for this struct was generated from the following file:

• interrupt/handler.h