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Update memcpy(3) to current coding style.

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This commit is contained in:
Jonas 'Sortie' Termansen 2014-09-25 15:15:36 +02:00
parent 163ecfcf55
commit fb7db21a1b
1 changed files with 45 additions and 55 deletions
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100
libc/string/memcpy.cpp
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@ -1,6 +1,6 @@
/******************************************************************************* /*******************************************************************************
Copyright(C) Jonas 'Sortie' Termansen 2011, 2012. Copyright(C) Jonas 'Sortie' Termansen 2011, 2012, 2014.
This file is part of the Sortix C Library. This file is part of the Sortix C Library.
@ -25,105 +25,95 @@
#include <stdint.h> #include <stdint.h>
#include <string.h> #include <string.h>
#if 8 < __SIZEOF_LONG__ inline static
#error unsigned long is bigger than expected, please add support to this file. void* memcpy_slow(void* restrict dst_ptr,
#endif const void* restrict src_ptr,
size_t size)
inline static void* memcpy_slow(void* restrict dstptr,
const void* restrict srcptr, size_t length)
{ {
uint8_t* restrict dst = (uint8_t* restrict) dstptr; unsigned char* restrict dst = (unsigned char* restrict) dst_ptr;
const uint8_t* restrict src = (const uint8_t* restrict) srcptr; const unsigned char* restrict src = (const unsigned char* restrict) src_ptr;
for ( size_t i = 0; i < length; i += sizeof(uint8_t) ) for ( size_t i = 0; i < size; i++ )
dst[i] = src[i]; dst[i] = src[i];
return dstptr; return dst_ptr;
} }
extern "C" void* memcpy(void* restrict dstptr, const void* restrict srcptr, extern "C"
size_t length) void* memcpy(void* restrict dst_ptr,
const void* restrict src_ptr,
size_t size)
{ {
const unsigned long unalignmask = sizeof(unsigned long) - 1; #if 8 < __SIZEOF_LONG__
const unsigned long srcunalign = (unsigned long) srcptr & unalignmask; #warning "you should add support for your unexpectedly large unsigned long."
const unsigned long dstunalign = (unsigned long) dstptr & unalignmask; return memcpy_slow(dst_ptr, src_ptr, size);
if ( srcunalign != dstunalign ) #else
return memcpy_slow(dstptr, srcptr, length); unsigned long unalign_mask = sizeof(unsigned long) - 1;
unsigned long src_unalign = (unsigned long) src_ptr & unalign_mask;
unsigned long dst_unalign = (unsigned long) dst_ptr & unalign_mask;
if ( src_unalign != dst_unalign )
return memcpy_slow(dst_ptr, src_ptr, size);
union union
{ {
unsigned long srcval; unsigned long srcval;
const uint8_t* restrict src8; const unsigned char* restrict src8;
const uint16_t* restrict src16; const uint16_t* restrict src16;
const uint32_t* restrict src32; const uint32_t* restrict src32;
const uint64_t* restrict src64; const uint64_t* restrict src64;
const unsigned long* restrict srcul; const unsigned long* restrict srcul;
}; };
srcval = (unsigned long) srcptr; srcval = (unsigned long) src_ptr;
union union
{ {
unsigned long dstval; unsigned long dstval;
uint8_t* restrict dst8; unsigned char* restrict dst8;
uint16_t* restrict dst16; uint16_t* restrict dst16;
uint32_t* restrict dst32; uint32_t* restrict dst32;
uint64_t* restrict dst64; uint64_t* restrict dst64;
unsigned long* restrict dstul; unsigned long* restrict dstul;
}; };
dstval = (unsigned long) dstptr; dstval = (unsigned long) dst_ptr;
if ( dstunalign ) if ( dst_unalign )
{ {
if ( 1 <= length && !(dstval & (1-1)) && (dstval & (2-1)) ) if ( 1 <= size && !(dstval & (1-1)) && (dstval & (2-1)) )
*dst8++ = *src8++, *dst8++ = *src8++,
length -= 1; size -= 1;
if ( 2 <= length && !(dstval & (2-1)) && (dstval & (4-1)) ) if ( 2 <= size && !(dstval & (2-1)) && (dstval & (4-1)) )
*dst16++ = *src16++, *dst16++ = *src16++,
length -= 2; size -= 2;
#if 8 <= __SIZEOF_LONG__ #if 8 <= __SIZEOF_LONG__
if ( 4 <= length && !(dstval & (4-1)) && (dstval & (8-1)) ) if ( 4 <= size && !(dstval & (4-1)) && (dstval & (8-1)) )
*dst32++ = *src32++, *dst32++ = *src32++,
length -= 4; size -= 4;
#endif #endif
} }
size_t numcopies = length / sizeof(unsigned long); size_t num_copies = size / sizeof(unsigned long);
#if 0 for ( size_t i = 0; i < num_copies; i++ )
#if defined(__x86_64__) || defined(__i386__)
unsigned long zeroed_numcopies;
#if defined(__x86_64__)
asm volatile ("rep movsq" : "=c"(zeroed_numcopies), "=S"(srcul), "=D"(dstul)
: "c"(numcopies), "S"(srcul), "D"(dstul)
: "memory");
#elif defined(__i386__)
asm volatile ("rep movsd" : "=c"(zeroed_numcopies), "=S"(srcul), "=D"(dstul)
: "c"(numcopies), "S"(srcul), "D"(dstul)
: "memory");
#endif
#endif
#else
for ( size_t i = 0; i < numcopies; i++ )
*dstul++ = *srcul++; *dstul++ = *srcul++;
#endif
length -= numcopies * sizeof(unsigned long); size -= num_copies * sizeof(unsigned long);
if ( length ) if ( size )
{ {
#if 8 <= __SIZEOF_LONG__ #if 8 <= __SIZEOF_LONG__
if ( 4 <= length ) if ( 4 <= size )
*dst32++ = *src32++, *dst32++ = *src32++,
length -= 4; size -= 4;
#endif #endif
if ( 2 <= length ) if ( 2 <= size )
*dst16++ = *src16++, *dst16++ = *src16++,
length -= 2; size -= 2;
if ( 1 <= length ) if ( 1 <= size )
*dst8++ = *src8++, *dst8++ = *src8++,
length -= 1; size -= 1;
} }
return dstptr; return dst_ptr;
#endif
} }