text: /*
   * this is the internal transfer function.
   *
   * HISTORY
   * 24-Nov-02  Christian Tismer  <tismer@tismer.com>
   *      needed to add another magic constant to insure
   *      that f in slp_eval_frame(PyFrameObject *f)
   *      gets included into the saved stack area.
   *      SLP_STACK_REFPLUS will probably be 1 in most cases.
   * 17-Sep-02  Christian Tismer  <tismer@tismer.com>
   *      after virtualizing stack save/restore, the
   *      stack size shrunk a bit. Needed to introduce
   *      an adjustment SLP_STACK_MAGIC per platform.
   * 15-Sep-02  Gerd Woetzel       <gerd.woetzel@GMD.DE>
   *      added support for SunOS sparc with gcc
   */
  
  #define SLP_STACK_REFPLUS 1
  
  #ifdef SLP_EVAL
  
  #include <sys/trap.h>
  
  #define SLP_STACK_MAGIC 0
  
  static int
  slp_switch(void)
  {
      register int *stackref, stsizediff;
  
      /* Put the stack pointer into stackref */
  
      /* Sparc special: at first, flush register windows
       */
      __asm__ volatile (
          "ta %1\n\t"
          "mov %%sp, %0"
          : "=r" (stackref) :  "i" (ST_FLUSH_WINDOWS));
  
      {   /* You shalt put SLP_SAVE_STATE into a local block */
  
          SLP_SAVE_STATE(stackref, stsizediff);
  
          /* Increment stack and frame pointer by stsizediff */
  
          /* Sparc special: at first load new return address.
             This cannot be done later, because the stack
             might be overwritten again just after SLP_RESTORE_STATE
             has finished. BTW: All other registers (l0-l7 and i0-i5)
             might be clobbered too.
           */
          __asm__ volatile (
              "ld [%0+60], %%i7\n\t"
              "add %1, %%sp, %%sp\n\t"
              "add %1, %%fp, %%fp"
              : : "r" (_cst->stack), "r" (stsizediff)
              : "%l0", "%l1", "%l2", "%l3", "%l4", "%l5", "%l6", "%l7",
                "%i0", "%i1", "%i2", "%i3", "%i4", "%i5");
  
          SLP_RESTORE_STATE();
  
          /* Run far away as fast as possible, don't look back at the sins.
           * The LORD rained down burning sulfur on Sodom and Gomorra ...
           */
  
          /* Sparc special: Must make it *very* clear to the CPU that
             it shouldn't look back into the register windows
           */
          __asm__ volatile ( "ta %0" : : "i" (ST_CLEAN_WINDOWS));
          return 0;
      }
  }
  
  #endif
  
  