Cheat Engine

[ParkourPenguin]

x87 and SSE are expansions of the x86 instruction set used for dealing with floating point numbers (i.e. value types float and double). It would be largely irrelevant in this context unless you are planning on doing floating point math.

Here's a basic summary of all the registers:

• EAX - general purpose register. Used for accumulating values (loose convention) and return values from subroutines (strict convention).
  
• ECX - general purpose register. Can be used as a counter in loops (common convention) and used by some instructions as a counter register (see REP prefix).
  
• EDX - general purpose register. Sometimes used as support for 64-bit numbers in a 32-bit process (EDX:EAX; e.g. DIV).
  
• EBX - general purpose register. Used to point to the base of an array (loose convention).
  
• ESI - general purpose register. Denotes the source of an operation (e.g. MOVSD; apart from relevant instructions, loose convention).
  
• EDI - general purpose register. Denotes the destination of an operation (apart from relevant instructions, loose convention).
  
• EBP - general purpose register. Commonly used to store the base of the current subroutine's stack frame (strict convention).
  
• ESP - while technically a general purpose register, this always points to the top of the stack (hardware-dependent convention). Severely modifying it without taking proper precautions will usually lead to the process crashing. Since push/pop are affected, you will need to store it some other way (i.e. in another register or in memory somewhere).
  
• EIP - cannot be manipulated like the general-purpose registers. This always points to the address of the next instruction to be executed (hardware-enforced convention).

Here's a version of that script I quickly optimized: