Question

I found this asm instructions who push a parameter into the stack before a call, but i think there is some useless instructions.

mov eax,esi
neg eax
sbb eax,eax
lea ecx,[esp+10h]
and eax,ecx
push eax

Can i just replace theses instructions with the following:

lea ecx,[esp+10h]
push ecx

Answer 1

No, I don’t believe what you have is equivalent. The sbb instruction may leave eax as zero (all 0 bits) or negative one (all 1 bits), which will definitely affect what happens to the value pulled from ecx in the and instruction.

It looks like the original code will push either esp+10h or 0, depending on what was in esi to start with.