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fix _BitScanReverse() usage for CE6

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This commit is contained in:
escherstair 2020-08-04 10:01:44 +02:00
parent f56928de85
commit 6364c8e5ab
1 changed files with 22 additions and 1 deletions
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23
include/rapidjson/internal/clzll.h
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@ -17,7 +17,7 @@
#include "../rapidjson.h" #include "../rapidjson.h"
#if defined(_MSC_VER) #if defined(_MSC_VER) && !defined(UNDER_CE)
#include <intrin.h> #include <intrin.h>
#if defined(_WIN64) #if defined(_WIN64)
#pragma intrinsic(_BitScanReverse64) #pragma intrinsic(_BitScanReverse64)
@ -38,6 +38,27 @@ inline uint32_t clzll(uint64_t x) {
unsigned long r = 0; unsigned long r = 0;
#if defined(_WIN64) #if defined(_WIN64)
_BitScanReverse64(&r, x); _BitScanReverse64(&r, x);
#elif defined(UNDER_CE)
// Scan the high 32 bits.
uint32_t high = static_cast<uint32_t>(x >> 32);
if (high != 0)
{
unsigned long index = 31;
while((high & (1U<<index)) == 0)
{
--index;
}
return index;
}
// Scan the low 32 bits.
uint32_t low =static_cast<uint32_t>(x & 0xFFFFFFFF);
unsigned long index = 31;
while((low & (1U<<index)) == 0)
{
--index;
}
return index;
#else #else
// Scan the high 32 bits. // Scan the high 32 bits.
if (_BitScanReverse(&r, static_cast<uint32_t>(x >> 32))) if (_BitScanReverse(&r, static_cast<uint32_t>(x >> 32)))