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  1. /*
  2.  * Copyright (c) 2007 Pavel Jancik
  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 libcarm32
  30.  * @{
  31.  */
  32. /** @file
  33.  *  @brief Syscall routine.
  34.  */
  35.  
  36. #include <libc.h>
  37.  
  38.  
  39. /** Syscall routine.
  40.  *
  41.  *  Stores p1-p4, id to r0-r4 registers and calls <code>swi</code>
  42.  *  instruction. Returned value is read from r0 register.
  43.  *
  44.  *  @param p1 Parameter 1.
  45.  *  @param p2 Parameter 2.
  46.  *  @param p3 Parameter 3.
  47.  *  @param p4 Parameter 4.
  48.  *  @param id Number of syscall.
  49.  *
  50.  *  @return Syscall return value.
  51.  */
  52. sysarg_t __syscall(const sysarg_t p1, const sysarg_t p2, const sysarg_t p3,
  53.     const sysarg_t p4, const syscall_t id)
  54. {
  55.     register sysarg_t __arm_reg_r0 asm("r0") = p1;
  56.     register sysarg_t __arm_reg_r1 asm("r1") = p2;
  57.     register sysarg_t __arm_reg_r2 asm("r2") = p3;
  58.     register sysarg_t __arm_reg_r3 asm("r3") = p4;
  59.     register sysarg_t __arm_reg_r4 asm("r4") = id;
  60.  
  61.     asm volatile ( "swi"
  62.         : "=r" (__arm_reg_r0)
  63.         : "r"  (__arm_reg_r0),
  64.           "r"  (__arm_reg_r1),
  65.           "r"  (__arm_reg_r2),
  66.           "r"  (__arm_reg_r3),
  67.           "r"  (__arm_reg_r4)
  68.     );
  69.  
  70.     return __arm_reg_r0;
  71. }
  72.  
  73. /** @}
  74.  */
  75.