/**************************************************************************** * File: libc/string/lib_vikmemcpy.c * * This is version of the optimized memcpy by Daniel Vik, adapted to the * NuttX environment. * * Copyright (C) 1999-2010 Daniel Vik * * Adaptations include: * - File name change * - Use of types defined in stdint.h * - Integration with the NuttX configuration system * - Other cosmetic changes for consistency with NuttX coding standards * * This software is provided 'as-is', without any express or implied * warranty. In no event will the authors be held liable for any * damages arising from the use of this software. * Permission is granted to anyone to use this software for any * purpose, including commercial applications, and to alter it and * redistribute it freely, subject to the following restrictions: * * 1. The origin of this software must not be misrepresented; you * must not claim that you wrote the original software. If you * use this software in a product, an acknowledgment in the * use this software in a product, an acknowledgment in the * product documentation would be appreciated but is not * required. * * 2. Altered source versions must be plainly marked as such, and * must not be misrepresented as being the original software. * * 3. This notice may not be removed or altered from any source * distribution. * * Description: Implementation of the standard library function memcpy. * This implementation of memcpy() is ANSI-C89 compatible. * * The following configuration options can be set: * * CONFIG_ENDIAN_BIG * Uses processor with big endian addressing. Default is little endian. * * CONFIG_MEMCPY_PRE_INC_PTRS * Use pre increment of pointers. Default is post increment of pointers. * * CONFIG_MEMCPY_INDEXED_COPY * Copying data using array indexing. Using this option, disables the * CONFIG_MEMCPY_PRE_INC_PTRS option. * * CONFIG_MEMCPY_64BIT - Compiles memcpy for 64 bit architectures * ****************************************************************************/ /**************************************************************************** * Configuration definitions. ****************************************************************************/ #define CONFIG_MEMCPY_INDEXED_COPY /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ /* Can't support CONFIG_MEMCPY_64BIT if the platform does not have 64-bit * integer types. */ #ifndef CONFIG_HAVE_LONG_LONG # undef CONFIG_MEMCPY_64BIT #endif /* Remove definitions when CONFIG_MEMCPY_INDEXED_COPY is defined */ #if defined (CONFIG_MEMCPY_INDEXED_COPY) # if defined (CONFIG_MEMCPY_PRE_INC_PTRS) # undef CONFIG_MEMCPY_PRE_INC_PTRS # endif /* CONFIG_MEMCPY_PRE_INC_PTRS */ #endif /* CONFIG_MEMCPY_INDEXED_COPY */ /* Definitions for pre and post increment of pointers */ #if defined (CONFIG_MEMCPY_PRE_INC_PTRS) # define START_VAL(x) (x)-- # define INC_VAL(x) *++(x) # define CAST_TO_U8(p, o) ((uint8_t*)p + o + TYPE_WIDTH) # define WHILE_DEST_BREAK (TYPE_WIDTH - 1) # define PRE_LOOP_ADJUST - (TYPE_WIDTH - 1) # define PRE_SWITCH_ADJUST + 1 #else /* CONFIG_MEMCPY_PRE_INC_PTRS */ # define START_VAL(x) # define INC_VAL(x) *(x)++ # define CAST_TO_U8(p, o) ((uint8_t*)p + o) # define WHILE_DEST_BREAK 0 # define PRE_LOOP_ADJUST # define PRE_SWITCH_ADJUST #endif /* CONFIG_MEMCPY_PRE_INC_PTRS */ /* Definitions for endian-ness */ #ifdef CONFIG_ENDIAN_BIG # define SHL << # define SHR >> #else /* CONFIG_ENDIAN_BIG */ # define SHL >> # define SHR << #endif /* CONFIG_ENDIAN_BIG */ /**************************************************************************** * Macros for copying words of different alignment. * Uses incremening pointers. ****************************************************************************/ #define CP_INCR() \ { \ INC_VAL(dstN) = INC_VAL(srcN); \ } #define CP_INCR_SH(shl, shr) \ { \ dstWord = srcWord SHL shl; \ srcWord = INC_VAL(srcN); \ dstWord |= srcWord SHR shr; \ INC_VAL(dstN) = dstWord; \ } /**************************************************************************** * Macros for copying words of different alignment. * Uses array indexes. ****************************************************************************/ #define CP_INDEX(idx) \ { \ dstN[idx] = srcN[idx]; \ } #define CP_INDEX_SH(x, shl, shr) \ { \ dstWord = srcWord SHL shl; \ srcWord = srcN[x]; \ dstWord |= srcWord SHR shr; \ dstN[x] = dstWord; \ } /**************************************************************************** * Macros for copying words of different alignment. * Uses incremening pointers or array indexes depending on * configuration. ****************************************************************************/ #if defined (CONFIG_MEMCPY_INDEXED_COPY) # define CP(idx) CP_INDEX(idx) # define CP_SH(idx, shl, shr) CP_INDEX_SH(idx, shl, shr) # define INC_INDEX(p, o) ((p) += (o)) #else /* CONFIG_MEMCPY_INDEXED_COPY */ # define CP(idx) CP_INCR() # define CP_SH(idx, shl, shr) CP_INCR_SH(shl, shr) # define INC_INDEX(p, o) #endif /* CONFIG_MEMCPY_INDEXED_COPY */ #define COPY_REMAINING(count) \ { \ START_VAL(dst8); \ START_VAL(src8); \ \ switch (count) \ { \ case 7: INC_VAL(dst8) = INC_VAL(src8); \ case 6: INC_VAL(dst8) = INC_VAL(src8); \ case 5: INC_VAL(dst8) = INC_VAL(src8); \ case 4: INC_VAL(dst8) = INC_VAL(src8); \ case 3: INC_VAL(dst8) = INC_VAL(src8); \ case 2: INC_VAL(dst8) = INC_VAL(src8); \ case 1: INC_VAL(dst8) = INC_VAL(src8); \ case 0: \ default: break; \ } \ } #define COPY_NO_SHIFT() \ { \ UIntN* dstN = (UIntN*)(dst8 PRE_LOOP_ADJUST); \ UIntN* srcN = (UIntN*)(src8 PRE_LOOP_ADJUST); \ size_t length = count / TYPE_WIDTH; \ \ while (length & 7) \ { \ CP_INCR(); \ length--; \ } \ \ length /= 8; \ \ while (length--) \ { \ CP(0); \ CP(1); \ CP(2); \ CP(3); \ CP(4); \ CP(5); \ CP(6); \ CP(7); \ \ INC_INDEX(dstN, 8); \ INC_INDEX(srcN, 8); \ } \ \ src8 = CAST_TO_U8(srcN, 0); \ dst8 = CAST_TO_U8(dstN, 0); \ \ COPY_REMAINING(count & (TYPE_WIDTH - 1)); \ \ return dest; \ } #define COPY_SHIFT(shift) \ { \ UIntN* dstN = (UIntN*)((((UIntN)dst8) PRE_LOOP_ADJUST) & \ ~(TYPE_WIDTH - 1)); \ UIntN* srcN = (UIntN*)((((UIntN)src8) PRE_LOOP_ADJUST) & \ ~(TYPE_WIDTH - 1)); \ size_t length = count / TYPE_WIDTH; \ UIntN srcWord = INC_VAL(srcN); \ UIntN dstWord; \ \ while (length & 7) \ { \ CP_INCR_SH(8 * shift, 8 * (TYPE_WIDTH - shift)); \ length--; \ } \ \ length /= 8; \ \ while (length--) \ { \ CP_SH(0, 8 * shift, 8 * (TYPE_WIDTH - shift)); \ CP_SH(1, 8 * shift, 8 * (TYPE_WIDTH - shift)); \ CP_SH(2, 8 * shift, 8 * (TYPE_WIDTH - shift)); \ CP_SH(3, 8 * shift, 8 * (TYPE_WIDTH - shift)); \ CP_SH(4, 8 * shift, 8 * (TYPE_WIDTH - shift)); \ CP_SH(5, 8 * shift, 8 * (TYPE_WIDTH - shift)); \ CP_SH(6, 8 * shift, 8 * (TYPE_WIDTH - shift)); \ CP_SH(7, 8 * shift, 8 * (TYPE_WIDTH - shift)); \ \ INC_INDEX(dstN, 8); \ INC_INDEX(srcN, 8); \ } \ \ src8 = CAST_TO_U8(srcN, (shift - TYPE_WIDTH)); \ dst8 = CAST_TO_U8(dstN, 0); \ \ COPY_REMAINING(count & (TYPE_WIDTH - 1)); \ \ return dest; \ } /**************************************************************************** * Type Definitions ****************************************************************************/ #ifdef CONFIG_MEMCPY_64BIT typedef uint64_t UIntN; # define TYPE_WIDTH 8L #else typedef uint32_t UIntN; # define TYPE_WIDTH 4L #endif /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: memcpy * * Description: * Copies count bytes from src to dest. No overlap check is performed. * * Input Parameters: * dest - pointer to destination buffer * src - pointer to source buffer * count - number of bytes to copy * * Returned Value: * A pointer to destination buffer * ****************************************************************************/ FAR void *memcpy(FAR void *dest, FAR const void *src, size_t count) { FAR uint8_t *dst8 = (FAR uint8_t *)dest; FAR uint8_t *src8 = (FAR uint8_t *)src; if (count < 8) { COPY_REMAINING(count); return dest; } START_VAL(dst8); START_VAL(src8); while (((UIntN)dst8 & (TYPE_WIDTH - 1)) != WHILE_DEST_BREAK) { INC_VAL(dst8) = INC_VAL(src8); count--; } switch ((((UIntN)src8) PRE_SWITCH_ADJUST) & (TYPE_WIDTH - 1)) { case 0: COPY_NO_SHIFT(); break; case 1: COPY_SHIFT(1); break; case 2: COPY_SHIFT(2); break; case 3: COPY_SHIFT(3); break; #if TYPE_WIDTH > 4 case 4: COPY_SHIFT(4); break; case 5: COPY_SHIFT(5); break; case 6: COPY_SHIFT(6); break; case 7: COPY_SHIFT(7); break; #endif } return dest; }