arch/ppc-all/kernel/createcontext.c

   1 /*
   2     Copyright © 1995-2014, The AROS Development Team. All rights reserved.
   3     $Id$
   4 */
   5
   6 #include <aros/kernel.h>
   7 #include <aros/libcall.h>
   8
   9 #include <kernel_base.h>
  10 #include <kernel_objects.h>
  11
  12 AROS_LH0I(void *, KrnCreateContext,
  13           struct KernelBase *, KernelBase, 18, Kernel)
  14 {
  15     AROS_LIBFUNC_INIT
  16
  17     struct ExceptionContext *ctx;
  18
  19     /* Allocate a new context */
  20     ctx = krnAllocCPUContext();
  21
  22     /* Initialize the context */
  23     if (ctx)
  24     {
  25         ULONG i;
  26
  27         /*
  28          * Sys V PPC ABI says r2 is reserved for TOC or SDATA2.
  29          * Here we copy the current value and it will never be
  30          * changed again. It is not needed for AROS but can be
  31          * needed for host OS. It is known to be needed for Linux
  32          * and won't harm anywhere else.
  33          */
  34         __asm__ __volatile__ ("stw 2,%0":"=m"(ctx->gpr[2])::"memory");
  35
  36         /* Initialize FPU portion */
  37         ctx->Flags = ECF_FPU;
  38         for (i = 0; i < 32; i++)
  39             ctx->fpr[i] = 0.0;
  40     }
  41
  42     return ctx;
  43
  44     AROS_LIBFUNC_EXIT
  45 }