Original code:

  // esi -> asciiz string
  // cl = character to remove

  mov edi, esi
  cld
  loop1:
      lodsb      // Load the byte from [esi] into al
      or al, al
       jz alldone
      cmp al, cl
       je loop1  // Skip this byte, since it's one we want to remove
      stosb      // Store the byte at [edi] from al
      jmp loop1  // Loop around for the next byte
  alldone:
      xor al, al
      stosb      // 0 terminate it

The only real behavioral change was that this version would cope with an input of cl=0. My cleaned up version would not cope with cl=0, but would need a sanity check for that.

Hmm. My memory must be faulty, but I don't remember the first one having the final xor and stosb. I do remember looking at your solution and thinking that you'd forgotten it, that's why I expressed an interest in seeing the original.

Still, likely my memory is at fault.

heheh my initial version also explicitly added the 0, and then I also found a way to do it in the loop. Seems a common evolution.

But your final solution is clearer than mine. While it uses an extra variable (register), it avoids looking up the same thing twice. So... more efficient and clearer.

BTW: TIL char * a = "hello"; doesn't work in C (I think it doesn't allocate memory). I'm actually happy enough that I could solve this at all, not having used C for 20 years ...old

Actually, I might just be tired. :-p I don't see anything wrong with axod's code. Just emailed you a fairly verbose C version. I hate writing production code...