What’s the difference between EAX, EBX, and ECX in assembly?
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 …
How exactly does the x86 LOOP instruction work? - Stack Overflow
Oct 23, 2017 · Use a smaller starting value for ecx so you get to the interesting ecx=1 part sooner. See also the x86 tag wiki for links to manuals, guides, and asm debugging tips at the bottom. And BTW, if …
assembly - Why take CMP ECX, ECX? - Stack Overflow
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 …
What does X mean in EAX,EBX,ECX ... in assembly?
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 …
assembly - How is "rax" different from "eax"? - Stack Overflow
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 …
The using rules of %eax, %edx, %ecx in the same function frame
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 …
what are the purpose of different types of assembly registers?
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, …
Are the data registers EAX, EBX, ECX and EDX interchangeable
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 …
What is the correct way to loop if I use ECX in loop (Assembly)
Mar 19, 2017 · The advantage of loop is that it uses less instruction bytes. Think of it as a code-size optimization you can use if ECX happens to be a convenient register for looping, but at the cost of …
What is the purpose of XORing a register with itself?
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 …