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  1. /*
  2.  * Copyright (c) 2005 Sergey Bondari
  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. #ifndef KERN_ia32_MEMSTR_H_
  36. #define KERN_ia32_MEMSTR_H_
  37.  
  38. /** Copy memory
  39.  *
  40.  * Copy a given number of bytes (3rd argument)
  41.  * from the memory location defined by 2nd argument
  42.  * to the memory location defined by 1st argument.
  43.  * The memory areas cannot overlap.
  44.  *
  45.  * @param dst Destination
  46.  * @param src Source
  47.  * @param cnt Number of bytes
  48.  * @return Destination
  49.  */
  50. static inline void * memcpy(void * dst, const void * src, size_t cnt)
  51. {
  52.         unative_t d0, d1, d2;
  53.  
  54.         asm volatile(
  55.                 /* copy all full dwords */
  56.                 "rep movsl\n\t"
  57.                 /* load count again */
  58.                 "movl %4, %%ecx\n\t"
  59.                 /* ecx = ecx mod 4 */
  60.                 "andl $3, %%ecx\n\t"
  61.                 /* are there last <=3 bytes? */
  62.                 "jz 1f\n\t"
  63.                 /* copy last <=3 bytes */
  64.                 "rep movsb\n\t"
  65.                 /* exit from asm block */
  66.                 "1:\n"
  67.                 : "=&c" (d0), "=&D" (d1), "=&S" (d2)
  68.                 : "0" ((unative_t) (cnt / 4)), "g" ((unative_t) cnt), "1" ((unative_t) dst), "2" ((unative_t) src)
  69.                 : "memory");
  70.  
  71.         return dst;
  72. }
  73.  
  74.  
  75. /** Compare memory regions for equality
  76.  *
  77.  * Compare a given number of bytes (3rd argument)
  78.  * at memory locations defined by 1st and 2nd argument
  79.  * for equality. If bytes are equal function returns 0.
  80.  *
  81.  * @param src Region 1
  82.  * @param dst Region 2
  83.  * @param cnt Number of bytes
  84.  * @return Zero if bytes are equal, non-zero otherwise
  85.  */
  86. static inline int memcmp(const void * src, const void * dst, size_t cnt)
  87. {
  88.     uint32_t d0, d1, d2;
  89.     int ret;
  90.    
  91.     asm (
  92.         "repe cmpsb\n\t"
  93.         "je 1f\n\t"
  94.         "movl %3, %0\n\t"
  95.         "addl $1, %0\n\t"
  96.         "1:\n"
  97.         : "=a" (ret), "=%S" (d0), "=&D" (d1), "=&c" (d2)
  98.         : "0" (0), "1" ((unative_t) src), "2" ((unative_t) dst), "3" ((unative_t) cnt)
  99.     );
  100.    
  101.     return ret;
  102. }
  103.  
  104. /** Fill memory with words
  105.  * Fill a given number of words (2nd argument)
  106.  * at memory defined by 1st argument with the
  107.  * word value defined by 3rd argument.
  108.  *
  109.  * @param dst Destination
  110.  * @param cnt Number of words
  111.  * @param x Value to fill
  112.  */
  113. static inline void memsetw(uintptr_t dst, size_t cnt, uint16_t x)
  114. {
  115.     uint32_t d0, d1;
  116.    
  117.     asm volatile (
  118.         "rep stosw\n\t"
  119.         : "=&D" (d0), "=&c" (d1), "=a" (x)
  120.         : "0" (dst), "1" (cnt), "2" (x)
  121.         : "memory"
  122.     );
  123.  
  124. }
  125.  
  126. /** Fill memory with bytes
  127.  * Fill a given number of bytes (2nd argument)
  128.  * at memory defined by 1st argument with the
  129.  * word value defined by 3rd argument.
  130.  *
  131.  * @param dst Destination
  132.  * @param cnt Number of bytes
  133.  * @param x Value to fill
  134.  */
  135. static inline void memsetb(uintptr_t dst, size_t cnt, uint8_t x)
  136. {
  137.     uint32_t d0, d1;
  138.    
  139.     asm volatile (
  140.         "rep stosb\n\t"
  141.         : "=&D" (d0), "=&c" (d1), "=a" (x)
  142.         : "0" (dst), "1" (cnt), "2" (x)
  143.         : "memory"
  144.     );
  145.  
  146. }
  147.  
  148. #endif
  149.  
  150. /** @}
  151.  */
  152.