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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 amd64  
  30.  * @{
  31.  */
  32. /** @file
  33.  */
  34.  
  35. #ifndef KERN_amd64_MEMSTR_H_
  36. #define KERN_amd64_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.                 "rep movsq\n\t"
  56.                 "movq %4, %%rcx\n\t"
  57.                 "andq $7, %%rcx\n\t"
  58.                 "jz 1f\n\t"
  59.                 "rep movsb\n\t"
  60.                 "1:\n"
  61.                 : "=&c" (d0), "=&D" (d1), "=&S" (d2)
  62.                 : "0" ((unative_t)(cnt / 8)), "g" ((unative_t)cnt), "1" ((unative_t) dst), "2" ((unative_t) src)
  63.                 : "memory");
  64.  
  65.         return dst;
  66. }
  67.  
  68.  
  69. /** Compare memory regions for equality
  70.  *
  71.  * Compare a given number of bytes (3rd argument)
  72.  * at memory locations defined by 1st and 2nd argument
  73.  * for equality. If bytes are equal function returns 0.
  74.  *
  75.  * @param src Region 1
  76.  * @param dst Region 2
  77.  * @param cnt Number of bytes
  78.  * @return Zero if bytes are equal, non-zero otherwise
  79.  */
  80. static inline int memcmp(const void * src, const void * dst, size_t cnt)
  81. {
  82.     unative_t d0, d1, d2;
  83.     unative_t ret;
  84.    
  85.     asm (
  86.         "repe cmpsb\n\t"
  87.         "je 1f\n\t"
  88.         "movq %3, %0\n\t"
  89.         "addq $1, %0\n\t"
  90.         "1:\n"
  91.         : "=a" (ret), "=%S" (d0), "=&D" (d1), "=&c" (d2)
  92.         : "0" (0), "1" (src), "2" (dst), "3" ((unative_t)cnt)
  93.     );
  94.    
  95.     return ret;
  96. }
  97.  
  98. /** Fill memory with words
  99.  * Fill a given number of words (2nd argument)
  100.  * at memory defined by 1st argument with the
  101.  * word value defined by 3rd argument.
  102.  *
  103.  * @param dst Destination
  104.  * @param cnt Number of words
  105.  * @param x Value to fill
  106.  */
  107. static inline void memsetw(uintptr_t dst, size_t cnt, uint16_t x)
  108. {
  109.     unative_t d0, d1;
  110.    
  111.     asm volatile (
  112.         "rep stosw\n\t"
  113.         : "=&D" (d0), "=&c" (d1), "=a" (x)
  114.         : "0" (dst), "1" ((unative_t)cnt), "2" (x)
  115.         : "memory"
  116.     );
  117.  
  118. }
  119.  
  120. /** Fill memory with bytes
  121.  * Fill a given number of bytes (2nd argument)
  122.  * at memory defined by 1st argument with the
  123.  * word value defined by 3rd argument.
  124.  *
  125.  * @param dst Destination
  126.  * @param cnt Number of bytes
  127.  * @param x Value to fill
  128.  */
  129. static inline void memsetb(uintptr_t dst, size_t cnt, uint8_t x)
  130. {
  131.     unative_t d0, d1;
  132.    
  133.     asm volatile (
  134.         "rep stosb\n\t"
  135.         : "=&D" (d0), "=&c" (d1), "=a" (x)
  136.         : "0" (dst), "1" ((unative_t)cnt), "2" (x)
  137.         : "memory"
  138.     );
  139.  
  140. }
  141.  
  142. #endif
  143.  
  144. /** @}
  145.  */
  146.