49 lines
862 B
C
49 lines
862 B
C
#include <string.h>
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#include <stdint.h>
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/*
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memset()
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Sets the contents of a memory area. A smart copy is performed.
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*/
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void *memset(void *d, int byte, size_t byte_number)
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{
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uint8_t *dest = (uint8_t *)d;
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unsigned short word = (byte << 8) | byte;
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unsigned int longword = (word << 16) | word;
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// When the area is small, simply copying using byte operations. The
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// minimum length used for long operations must be at least 3.
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if(byte_number < 8)
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{
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while(byte_number)
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{
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*dest++ = byte;
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byte_number--;
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}
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return d;
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}
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// Reaching a long offset.
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while((intptr_t)dest & 3)
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{
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*dest++ = byte;
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byte_number--;
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}
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// Copying using long operations.
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while(byte_number >= 4)
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{
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*((uint32_t *)dest) = longword;
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dest += 4;
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byte_number -= 4;
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}
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// Ending the copy.
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while(byte_number)
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{
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*dest++ = byte;
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byte_number--;
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}
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return d;
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}
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