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 …

Sep 14, 2012 · I see code with push ecx and I don't know its purpose. Does it change the value of ecx to something else?

Jul 7, 2023 · The LOOP instructions assume that the CX, ECX, or RCX register contains the loop count. loop loopnz loopne loopz loope Jumps Jump instructions that perform a jump if the CX, ECX, or RCX …

Apr 8, 2013 · The ECX register contains CX in its lower part, which contains CH and CL as represented in the picture below. When modifying the value stored in CL, you also change CX and ECX, but not CH.

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 …

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 …

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 …