arch/i386-all/kernel/cpu_init.c

   1 /*
   2     Copyright © 1995-2014, The AROS Development Team. All rights reserved.
   3     $Id$
   4 */
   5
   6 #include <aros/config.h>
   7 #include <aros/symbolsets.h>
   8 #include <asm/cpu.h>
   9 #include <exec/types.h>
  10 #include <aros/i386/cpucontext.h>
  11
  12 #include "kernel_base.h"
  13 #include "kernel_debug.h"
  14
  15 #define D(x)
  16
  17 #ifndef SIZEOF_8087_FRAME
  18 #define SIZEOF_8087_FRAME sizeof(struct FPUContext)
  19 #endif
  20
  21 static int cpu_Init(struct KernelBase *KernelBase)
  22 {
  23     ULONG v1, v2, v3, v4;
  24
  25     D(bug("[Kernel] cpu_Init(0x%p) for i386\n", KernelBase));
  26
  27     KernelBase->kb_ContextSize = sizeof(struct AROSCPUContext);
  28
  29     /* Evaluate CPU capabilities */
  30     asm volatile("cpuid":"=a"(v1),"=b"(v2),"=c"(v3),"=d"(v4):"a"(1));
  31
  32     if (v4 & (1 << 24))
  33     {
  34         switch ((v4 >> 25) & 3)
  35         {
  36         case 3:
  37         case 2:
  38         case 1:
  39             /* FPU + SSE */
  40
  41 #if (AROS_FLAVOUR & AROS_FLAVOUR_STANDALONE)
  42             /* tell the CPU that we will support SSE */
  43             wrcr(cr4, rdcr(cr4) | (3 << 9));
  44             /* Clear the EM and MP flags of CR0 */
  45             wrcr(cr0, rdcr(cr0) & ~6);
  46 #endif
  47
  48 #ifdef USE_LEGACY_8087
  49             KernelBase->kb_ContextFlags = ECF_FPU|ECF_FPX;
  50             KernelBase->kb_ContextSize += SIZEOF_8087_FRAME;              /* Legacy 8087 frame with private portion */
  51 #else
  52             KernelBase->kb_ContextFlags = ECF_FPX;
  53 #endif
  54             KernelBase->kb_ContextSize += sizeof(struct FPXContext) + 15; /* Add 15 bytes for alignment */
  55             break;
  56         }
  57     }
  58     else
  59     {
  60         /* FPU only */
  61         KernelBase->kb_ContextFlags = ECF_FPU;
  62         KernelBase->kb_ContextSize += SIZEOF_8087_FRAME;
  63     }
  64
  65     D(bug("[Kernel] CPU context flags: 0x%08X\n", KernelBase->kb_ContextFlags));
  66
  67     return TRUE;
  68 }
  69
  70 ADD2INITLIB(cpu_Init, 5);