How do these machine codes work for jump counter?

[lwcw123]

I tried to look for the machine code of jump counter for a game and found the following:

The jump counter has a value of 8 while jumping and 0 while on ground. The address, which stores the value, has been verified. When the value is locked at 8, the character can no longer jump but show continuous landing action. However, I cannot understand the codes below. The first set of code is related to the process which change the value of jump counter from 0 to 8 while the second set of codes does the opposite.

**********************************
pop esi
pop ebx
movzx eax,byte ptr[eax+edx]
ret
mov eax,[esi+08]

**********************************
add eax,eax
mov eax,[edi+eax*8+28]
sub [eax+edx].cl
mov eax,[esi+08]

***********************************

The codes do not look like any example that I can find online related to jump counter logic and hacking for infinite jump. No matter how I alter this code, I simply made the program crashed.

Does anyone know how I shall proceed for infinite jump hack? Thanks a lot.

[Rhark]

Have you checked what addresses these instructions access to check if they are accessing multiple addresses? Could explain the crashing when trying to modify them.