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#include "GrCommon.h"
#include "GrDebug.h"
namespace gr
{
/*----------------------------------------------------------------------------------------------
Swap two blocks of size cb starting at pv1 and pv2. Doesn't handle overlapping blocks.
----------------------------------------------------------------------------------------------*/
void SwapBytes(void * pv1, void * pv2, int cb)
{
Assert((byte *)pv1 + cb <= (byte *)pv2 || (byte *)pv2 + cb <= (byte *)pv1);
AssertPtrSize(pv1, cb);
AssertPtrSize(pv2, cb);
#ifdef NO_ASM
byte *pb1 = (byte *)pv1;
byte *pb2 = (byte *)pv2;
byte b;
while (--cb >= 0)
{
b = *pb1;
*pb1++ = *pb2;
*pb2++ = b;
}
#else // !NO_ASM
__asm
{
// edi -> memory to swap, first pointer
// esi -> memory to swap, second pointer
mov edi,pv1
mov esi,pv2
mov ecx,cb
shr ecx,2
jz LBytes
LIntLoop:
mov eax,[edi]
mov ebx,[esi]
mov [edi],ebx
mov [esi],eax
add edi,4
add esi,4
dec ecx
jnz LIntLoop;
LBytes:
mov ecx,cb
and ecx,3
jz LDone
LByteLoop:
mov al,[edi]
mov bl,[esi]
mov [edi],bl
mov [esi],al
inc edi
inc esi
dec ecx
jnz LByteLoop
LDone:
}
#endif //!NO_ASM
}
/*----------------------------------------------------------------------------------------------
Fills a block of memory with the given short value.
----------------------------------------------------------------------------------------------*/
void FillShorts(void * pv, short sn, int csn)
{
AssertPtrSize(pv, csn * isizeof(short));
#ifdef NO_ASM
short * psn = (short *)pv;
short * psnLim = psn + csn;
while (psn < psnLim)
*psn++ = sn;
#else // !NO_ASM
__asm
{
// Setup the registers for using REP STOS instruction to set memory.
// NOTE: Alignment does not effect the speed of STOS.
//
// edi -> memory to set
// eax = value to store in destination
// direction flag is clear for auto-increment
mov edi,pv
mov ax,sn
mov ecx,csn
mov edx,ecx
and edx,1
jz LInts
// set 1 short
stosw
LInts:
shr ecx,1
jz LDone
mov ebx,eax
shl eax,16
mov ax,bx
rep stosd
LDone:
}
#endif //!NO_ASM
}
/***********************************************************************************************
Integer utilities.
***********************************************************************************************/
/*
* table of powers of 2, and largest prime smaller than each power of 2
* n 2**n prime diff
* --- ---------- ---------- ----
* 2: 4 3 ( -1)
* 3: 8 7 ( -1)
* 4: 16 13 ( -3)
* 5: 32 31 ( -1)
* 6: 64 61 ( -3)
* 7: 128 127 ( -1)
* 8: 256 251 ( -5)
* 9: 512 509 ( -3)
* 10: 1024 1021 ( -3)
* 11: 2048 2039 ( -9)
* 12: 4096 4093 ( -3)
* 13: 8192 8191 ( -1)
* 14: 16384 16381 ( -3)
* 15: 32768 32749 (-19)
* 16: 65536 65521 (-15)
* 17: 131072 131071 ( -1)
* 18: 262144 262139 ( -5)
* 19: 524288 524287 ( -1)
* 20: 1048576 1048573 ( -3)
* 21: 2097152 2097143 ( -9)
* 22: 4194304 4194301 ( -3)
* 23: 8388608 8388593 (-15)
* 24: 16777216 16777213 ( -3)
* 25: 33554432 33554393 (-39)
* 26: 67108864 67108859 ( -5)
* 27: 134217728 134217689 (-39)
* 28: 268435456 268435399 (-57)
* 29: 536870912 536870909 ( -3)
* 30: 1073741824 1073741789 (-35)
* 31: 2147483648 2147483647 ( -1)
* 32: 4294967296 4294967291 ( -5)
*/
const static unsigned int g_rguPrimes[] = {
3, 7, 13, 31, 61, 127, 251, 509, 1021, 2039, 4093, 8191, 16381, 32749, 65521, 131071,
262139, 524287, 1048573, 2097143, 4194301, 8388593, 16777213, 33554393, 67108859,
134217689, 268435399, 536870909, 1073741789, 2147483647, 4294967291U
};
/*----------------------------------------------------------------------------------------------
Returns the prime in g_rguPrimes that is closest to u.
----------------------------------------------------------------------------------------------*/
unsigned int GetPrimeNear(unsigned int u)
{
int cu = isizeof(g_rguPrimes) / isizeof(unsigned int);
int iuMin;
int iuLim;
int iu;
for (iuMin = 0, iuLim = cu; iuMin < iuLim; )
{
iu = (iuMin + iuLim) / 2;
if (u > g_rguPrimes[iu])
iuMin = iu + 1;
else
iuLim = iu;
}
Assert(iuMin == cu || iuMin < cu && u <= g_rguPrimes[iuMin]);
Assert(iuMin == 0 || iuMin > 0 && u > g_rguPrimes[iuMin - 1]);
if (!iuMin)
return g_rguPrimes[0];
if (iuMin == cu)
return g_rguPrimes[cu - 1];
if (g_rguPrimes[iuMin] - u < u - g_rguPrimes[iuMin - 1])
return g_rguPrimes[iuMin];
return g_rguPrimes[iuMin - 1];
}
/*----------------------------------------------------------------------------------------------
Returns the prime in g_rguPrimes that is larger than u or is the largest in the list.
----------------------------------------------------------------------------------------------*/
unsigned int GetLargerPrime(unsigned int u)
{
int cu = isizeof(g_rguPrimes) / isizeof(unsigned int);
int iuMin;
int iuLim;
int iu;
for (iuMin = 0, iuLim = cu; iuMin < iuLim; )
{
iu = (iuMin + iuLim) / 2;
if (u >= g_rguPrimes[iu])
iuMin = iu + 1;
else
iuLim = iu;
}
Assert(iuMin == cu || iuMin < cu && u < g_rguPrimes[iuMin]);
Assert(iuMin == 0 || iuMin > 0 && u >= g_rguPrimes[iuMin - 1]);
if (iuMin == cu)
return g_rguPrimes[cu - 1];
return g_rguPrimes[iuMin];
}
/*----------------------------------------------------------------------------------------------
Returns the prime in g_rguPrimes that is smaller than u or is the smallest in the list.
----------------------------------------------------------------------------------------------*/
unsigned int GetSmallerPrime(unsigned int u)
{
int cu = isizeof(g_rguPrimes) / isizeof(unsigned int);
int iuMin;
int iuLim;
int iu;
for (iuMin = 0, iuLim = cu; iuMin < iuLim; )
{
iu = (iuMin + iuLim) / 2;
if (u > g_rguPrimes[iu])
iuMin = iu + 1;
else
iuLim = iu;
}
Assert(iuMin == cu || iuMin < cu && u <= g_rguPrimes[iuMin]);
Assert(iuMin == 0 || iuMin > 0 && u > g_rguPrimes[iuMin - 1]);
if (!iuMin)
return g_rguPrimes[0];
return g_rguPrimes[iuMin - 1];
}
}
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