Author Archives: jeffrin

modify all segment registers except ..(CS)

software | Windows | In computing, a code segment, also known as a text segment or simply as text, is a phrase used to refer to a portion of memory or of an object file that contains executable instructions. source : http://en.wikipedia.org/wiki/Code_segment Note that code may always modify all segment registers except CS (the code …

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eip in 32-bit mode and rip in 64-bit mode

ABOUT Processor Register In computer architecture, a processor register is a quickly accessible location available to a computer’s central processing unit (CPU). Registers usually consist of a small amount of fast storage, although some registers have specific hardware functions, and may be read-only or write-only. Registers are typically addressed by mechanisms other than main memory, …

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eip in 32-bit mode,, and rip in 64-bit mode

software | Windows | The instruction pointer is called ip in 16-bit mode, eip in 32-bit mode,, and rip in 64-bit mode. The instruction pointer register points to the memory address which the processor will next attempt to execute; it cannot be directly accessed in 16-bit or 32-bit mode, but a sequence like the following …

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The Intel IA32 processors have a base pointer..

software | Windows | The Intel IA32 processors have a base pointer register called EBP . The EBP register is typically set to the value of the ESP register at the beginning of a procedure, and used to address the procedure arguments and locally allocated variables throughout the procedure. Thus, the arguments are located at …

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Register EDI holds the bit offset …

software | Windows | EDI: The Destination Index Every loop that generates data must store the result in memory, and doing so requires a moving pointer. The destination index, EDI, is that pointer. The destination index holds the implied write address of all string operations. The most useful string instruction, remarkably enough, is the seldom-used …

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16 bits into the segment register…(GS)

software | Windows | These instructions read a full pointer from memory and store it in the selected segment register:register pair. The full pointer loads 16 bits into the segment register SS, DS, ES, FS, or GS source : http://pdos.csail.mit.edu/6.828/2008/readings/i386/LGS.htm software |GNU/Linux| (gdb) info registers rax 0xfffffffffffffdfc -516 rbx 0x5dc 1500 rcx 0xffffffffffffffff -1 rdx …

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inferior's auxiliary vector…

(gdb) info auxv 33 AT_SYSINFO_EHDR System-supplied DSO’s ELF header 0x7fff7a9ff000 16 AT_HWCAP Machine-dependent CPU capability hints 0x78bfbff 6 AT_PAGESZ System page size 4096 17 AT_CLKTCK Frequency of times() 100 3 AT_PHDR Program headers for program 0x400040 4 AT_PHENT Size of program header entry 56 5 AT_PHNUM Number of program headers 8 7 AT_BASE Base address …

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inferior’s auxiliary vector…

(gdb) info auxv 33 AT_SYSINFO_EHDR System-supplied DSO’s ELF header 0x7fff7a9ff000 16 AT_HWCAP Machine-dependent CPU capability hints 0x78bfbff 6 AT_PAGESZ System page size 4096 17 AT_CLKTCK Frequency of times() 100 3 AT_PHDR Program headers for program 0x400040 4 AT_PHENT Size of program header entry 56 5 AT_PHNUM Number of program headers 8 7 AT_BASE Base address …

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