Nov 11, 2022 · 36 eax, ebx, ecx and so on are actually registers, which can be seen as "hardware" variables, somewhat similar to higher level-language's variables. Registers can be used in your …

May 12, 2016 · 2 If the ECX register is zero then the repe cmpsb is not executed at all. This means that the following setb and seta instructions would produce garbage! Thus the programmer chose to …

Mar 30, 2010 · The following is a brief explanation of what each of the x86 general-purpose registers stands for: EAX: "Extended Accumulator" - used for arithmetic and logical operations, as well as for …

Jul 14, 2020 · eax, ecx and edx are scratch registers, they don't have to be preserved across function calls. All other 32-bit general-purpose registers must be saved on the stack, which costs additional …

Jun 10, 2014 · For example, rep stos instructions use ECX as a counter and stored data into the memory pointed to by EDI. Nowadays, specialized instructions like that are not as commonly seen, …

Nov 18, 2018 · For example, for the write system call, it grabs the file descriptor from ebx, a pointer to the buffer you want to write from ecx and the number of bytes you want to write from edx. The kernel …

Also to avoid 0s when compiled as used on shell codes for exploitation of buffer overflows, etc. Why avoid the 0 ? Well, 0 represents the end of string in c/c++ and the shell code would be truncated if …

Jul 7, 2017 · while in the book the registers are: eax, ecx, edx, ebx, esp, ebp, esi, edi, eip, eflags, cs, ss, ds, es, fs, gs Can someone explain why they are different? I'm running on an AMD cpu; does AMD …

imul also has an immediate form: imul ecx, ebx, 1234 does ecx = ebx * 1234. Many assemblers will accept imul ecx, 1234 as short-hand for imul ecx, ecx, 1234. These 32x32 => 32-bit forms of imul …

Mar 25, 2011 · On my machine, this prints eax, ecx, and other standard registers hidden by info registers. This should probably be the accepted answer.