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  1. /*
  2.  * Copyright (c) 2005 Jakub Vana
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. /** @addtogroup ia32   
  30.  * @{
  31.  */
  32. /** @file
  33.  *
  34.  */
  35.  
  36. #include <fpu_context.h>
  37. #include <arch.h>
  38. #include <cpu.h>
  39.  
  40. typedef void (*fpu_context_function)(fpu_context_t *fctx);
  41.  
  42. static fpu_context_function fpu_save, fpu_restore;
  43.  
  44. static void fpu_context_f_save(fpu_context_t *fctx)
  45. {
  46.     asm volatile (
  47.         "fnsave %[fctx]"
  48.         : [fctx] "=m" (*fctx)
  49.     );
  50. }
  51.  
  52. static void fpu_context_f_restore(fpu_context_t *fctx)
  53. {
  54.     asm volatile (
  55.         "frstor %[fctx]"
  56.         : [fctx] "=m" (*fctx)
  57.     );
  58. }
  59.  
  60. static void fpu_context_fx_save(fpu_context_t *fctx)
  61. {
  62.     asm volatile (
  63.         "fxsave %[fctx]"
  64.         : [fctx] "=m" (*fctx)
  65.     );
  66. }
  67.  
  68. static void fpu_context_fx_restore(fpu_context_t *fctx)
  69. {
  70.     asm volatile (
  71.         "fxrstor %[fctx]"
  72.         : [fctx] "=m" (*fctx)
  73.     );
  74. }
  75.  
  76. /* Setup using fxsr instruction */
  77. void fpu_fxsr(void)
  78. {
  79.     fpu_save=fpu_context_fx_save;
  80.     fpu_restore=fpu_context_fx_restore;
  81. }
  82.  
  83. /* Setup using not fxsr instruction */
  84. void fpu_fsr(void)
  85. {
  86.     fpu_save = fpu_context_f_save;
  87.     fpu_restore = fpu_context_f_restore;
  88. }
  89.  
  90. void fpu_context_save(fpu_context_t *fctx)
  91. {
  92.     fpu_save(fctx);
  93. }
  94.  
  95. void fpu_context_restore(fpu_context_t *fctx)
  96. {
  97.     fpu_restore(fctx);
  98. }
  99.  
  100. void fpu_init()
  101. {
  102.     uint32_t help0 = 0;
  103.     uint32_t help1 = 0;
  104.    
  105.     asm volatile (
  106.         "fninit\n"
  107.         "stmxcsr %[help0]\n"
  108.         "mov %[help0], %[help1]\n"
  109.         "or %[magic], %[help1]\n"
  110.         "mov %[help1], %[help0]\n"
  111.         "ldmxcsr %[help0]\n"
  112.         : [help0] "+m" (help0), [help1] "+r" (help1)
  113.         : [magic] "i" (0x1f80)
  114.     );
  115. }
  116.  
  117. /** @}
  118.  */
  119.