arch/ppc-all/kernel/createcontext.c

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