libgloss/i960/crt0.c

   1 extern int main(int argc, char **argv, char **envp);
   2 extern int brk (void *value);
   3
   4 extern char bss_start;
   5 extern char end;
   6
   7 char *__env[1] = {0};
   8 char **environ = __env;
   9
  10 #define ENABLE_TRACE_MASK 1
  11
  12 __inline static void
  13 enable_tracing (void)
  14 {
  15     register int mask = ENABLE_TRACE_MASK;
  16     __asm__ volatile ("modpc %0,%0,%0"
  17                       :
  18                       : "d" (mask));
  19 }
  20
  21 #define STACK_ALIGN 64
  22
  23 __inline static void
  24 set_stack (void* ptr)
  25 {
  26     ptr = (void *)(((int)ptr + STACK_ALIGN - 1) & ~(STACK_ALIGN - 1));
  27     /* SP must be 64 bytes larger than FP at start.  */
  28     __asm__ volatile ("mov %0,sp"
  29                       :
  30                       : "d" (ptr+STACK_ALIGN));
  31     __asm__ volatile ("mov %0,fp"
  32                       :
  33                       : "d" (ptr));
  34 }
  35
  36 __inline static void
  37 init_Cregs (void)
  38 {
  39     /* set register values gcc like */
  40     register unsigned int mask0=0x3b001000;
  41     register unsigned int mask1=0x00009107;
  42     __asm__ volatile ("mov   %0,g14"
  43                       :                      /* no output */
  44                       : "I" (0));            /* gnu structure pointer */
  45     __asm__ volatile ("modac %1,%0,%0"
  46                       :                      /* no output */
  47                       : "d" (mask0),
  48                         "d" (mask1));        /* fpu control kb */
  49 }
  50
  51 void
  52 _start(void)
  53 {
  54   char *p;
  55
  56   enable_tracing ();
  57   set_stack (&end);
  58   init_Cregs ();
  59   /* The stack grows upwards, so this makes the heap start after a 256K
  60      stack area.  PlumHall known to fail with less than 73K of stack.  */
  61   brk (&end+0x40000);
  62   /* clear bss */
  63   memset (&bss_start, 0, &end - &bss_start);
  64   main(0, 0, 0);
  65   exit(0);
  66 }