reactos/boot/freeldr/freeldr/arch/i386/_alloca.S

   1 /* stuff needed for libgcc on win32.  */
   2
   3 /*#ifdef L_chkstk*/
   4 #ifdef WIN32
   5
   6         .global ___chkstk
   7         .global __alloca
   8 ___chkstk:
   9 __alloca:
  10         pushl  %ecx             /* save temp */
  11         movl   %esp,%ecx        /* get sp */
  12         addl   $0x8,%ecx        /* and point to return addr */
  13
  14 probe:  cmpl   $0x1000,%eax     /* > 4k ?*/
  15         jb    done
  16
  17         subl   $0x1000,%ecx             /* yes, move pointer down 4k*/
  18         orl    $0x0,(%ecx)              /* probe there */
  19         subl   $0x1000,%eax             /* decrement count */
  20         jmp    probe                    /* and do it again */
  21
  22 done:   subl   %eax,%ecx
  23         orl    $0x0,(%ecx)      /* less that 4k, just peek here */
  24
  25         movl   %esp,%eax
  26         movl   %ecx,%esp        /* decrement stack */
  27
  28         movl   (%eax),%ecx      /* recover saved temp */
  29         movl   4(%eax),%eax     /* get return address */
  30         jmp    *%eax
  31
  32
  33 #endif