About LOCAL string

[jj2007]

For the lazy programmer - short and fast, works with all kind of LOCAL variables, including strings and structures:

MyTest proc
LOCAL MyVar1:DWORD, LocBuffer[120]:BYTE, MyVar2:DWORD
  call ClearLocals
  ret
MyTest endp

Code Select Expand

ClearLocals proc ; put "call ClearLocals" as first instruction after LOCALS - eax will be unchanged on exit
  push eax ; do not use with uses esi etc - push them manually behind the call!
  lea eax, [esp+8] ; pushed eax and ret address
  mov esp, ebp ; base page of calling procedure
  align 4 ; 74 instead of 123 cycles on Celeron M, no effect on P4
@@:
  push 0 ; 120 bytes: 196 cycles on P4
  cmp esp, eax ; rep stosd??
  ja @B
  sub esp, 8 ; 19 bytes with align 4
  pop eax
  ret
ClearLocals endp


[NightWare]

LOCAL szDir[124]:BYTE

how to initialize it to all 0? like this szBuffer db 124 dup(0)

when i define a LOCAL Var, what is the default value inside?

to init/re-init a string you just need to clean the first byte, here :
mov BYTE PTR szDir,0
coz there is NO REASONS to clean the entire area (at least if your string functions are well coded...).

[ecube]

You guys like the caps...I tend to use buffers for alot more than strings, and that's why I recommended the full clearing, is a piece of mind for me and doesn't limit. If he's sure he's just gonna mess with strings then YEAH, clearing the first byte is sufficient.