reactos/lib/msvcrt/setjmp/setjmp.c

   1 /* Copyright (C) 1995 DJ Delorie, see COPYING.DJ for details */
   2 /* modified by Boudewijn Dekker */
   3 /* ms uses a smaller jmp_buf structure */
   4 /* might do a realloc in setjmp */
   5
   6 typedef struct {
   7   unsigned int __eax, __ebx, __ecx, __edx, __esi;
   8   unsigned int __edi, __ebp, __esp, __eip, __eflags;
   9   unsigned short __cs, __ds, __es, __fs, __gs, __ss;
  10   unsigned long __sigmask; /* for POSIX signals only */
  11   unsigned long __signum; /* for expansion */
  12   unsigned long __exception_ptr; /* pointer to previous exception */
  13   unsigned char __fpu_state[108]; /* for future use */
  14 } jmp_buf[1];
  15
  16
  17 /* jumps back to position specified in jmp_buf */
  18
  19 int longjmp( jmp_buf env, int value )
  20 {
  21   //push ebp             generated by the compiler
  22   //mov ebp, esp
  23
  24 #ifdef __GNUC__
  25   __asm__ __volatile__ (
  26         "movl   8(%ebp),%edi\n\t"       /* get jmp_buf */
  27         "movl   12(%ebp),%eax\n\t"      /* store retval in j->eax */
  28         "movl   %eax,0(%edi)\n\t"
  29
  30         "movw   46(%edi),%fs\n\t"
  31         "movw   48(%edi),%gs\n\t"
  32         "movl   4(%edi),%ebx\n\t"
  33         "movl   8(%edi),%ecx\n\t"
  34         "movl   12(%edi),%edx\n\t"
  35         "movl   24(%edi),%ebp\n\t"
  36
  37         /* Now for some uglyness.  The jmp_buf structure may be ABOVE the
  38            point on the new SS:ESP we are moving to.  We don't allow overlap,
  39            but do force that it always be valid.  We will use ES:ESI for
  40            our new stack before swapping to it.  */
  41
  42         "movw   50(%edi),%es\n\t"
  43         "movl   28(%edi),%esi\n\t"
  44         "subl   $28,%esi\n\t"   /* We need 7 working longwords on stack */
  45
  46         "movl   60(%edi),%eax\n\t"
  47         "es\n\t"
  48         "movl   %eax,(%esi)\n\t"        /* Exception pointer */
  49
  50         "movzwl 42(%edi),%eax\n\t"
  51         "es\n\t"
  52         "movl   %eax,4(%esi)\n\t"       /* DS */
  53
  54         "movl   20(%edi),%eax\n\t"
  55         "es\n\t"
  56         "movl   %eax,8(%esi)\n\t"       /* EDI */
  57
  58         "movl   16(%edi),%eax\n\t"
  59         "es\n\t"
  60         "movl   %eax,12(%esi)\n\t"      /* ESI */
  61
  62         "movl   32(%edi),%eax\n\t"
  63         "es\n\t"
  64         "movl   %eax,16(%esi)\n\t"      /* EIP - start of IRET frame */
  65
  66         "movl   40(%edi),%eax\n\t"
  67         "es\n\t"
  68         "movl   %eax,20(%esi)\n\t"      /* CS */
  69
  70         "movl   36(%edi),%eax\n\t"
  71         "es\n\t"
  72         "movl   %eax,24(%esi)\n\t"      /* EFLAGS */
  73
  74         "movl   0(%edi),%eax\n\t"
  75         "movw   44(%edi),%es\n\t"
  76
  77         "movw   50(%edi),%ss\n\t"
  78         "movl   %esi,%esp\n\t"
  79
  80         //"popl ___djgpp_exception_state_ptr\n\t"
  81         "popl   %edi\n\t"       // dummy popl instead of djgpp_exception_state_ptr
  82         "popl   %ds\n\t"
  83         "popl   %edi\n\t"
  84         "popl   %esi\n\t"
  85
  86         "iret\n\t"              /* actually jump to new cs:eip loading flags */
  87         );
  88
  89 #else
  90 #endif /*__GNUC__*/
  91   return value; // dummy return never reached
  92 }
  93
  94 #ifdef __GNUC__
  95
  96 int _setjmp( jmp_buf env )
  97 {
  98   //push ebp             generated by the compiler
  99   //mov ebp, esp
 100   __asm__ __volatile__ (
 101         "pushl  %edi\n\t"
 102         "movl   8(%ebp),%edi\n\t"
 103
 104         "movl   %eax, (%edi)\n\t"
 105         "movl   %ebx,4(%edi)\n\t"
 106         "movl   %ecx,8(%edi)\n\t"
 107         "movl   %edx,12(%edi)\n\t"
 108         "movl   %esi,16(%edi)\n\t"
 109
 110         "movl   -4(%ebp),%eax\n\t"
 111         "movl   %eax,20(%edi)\n\t"
 112
 113         "movl   (%ebp),%eax\n\t"
 114         "movl   %eax,24(%edi)\n\t"
 115
 116         "movl   %esp,%eax\n\t"
 117         "addl   $12,%eax\n\t"
 118         "movl   %eax,28(%edi)\n\t"
 119
 120         "movl   4(%ebp),%eax\n\t"
 121         "movl   %eax,32(%edi)\n\t"
 122
 123         "pushfl\n\t"
 124         "popl   36(%edi)\n\t"
 125
 126         "movw   %cs, 40(%edi)\n\t"
 127         "movw   %ds, 42(%edi)\n\t"
 128         "movw   %es, 44(%edi)\n\t"
 129         "movw   %fs, 46(%edi)\n\t"
 130         "movw   %gs, 48(%edi)\n\t"
 131         "movw   %ss, 50(%edi)\n\t"
 132
 133         //movl  ___djgpp_exception_state_ptr, %eax
 134         //movl  %eax, 60(%edi)
 135
 136         "popl   %edi\n\t"
 137         );
 138   return 0;
 139 }
 140
 141 #else
 142 #endif /*__GNUC__*/