misc.cpp

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//---------------------------------------------------------------------------
//
// Misc.cpp: Miscellaneous Routines
//
//---------------------------------------------------------------------------

#include "StdAfx.h"
#include "Misc.h"

static int RandSeed = 0;

__int64 __declspec(naked) ReadTSC()
{
    __asm
    {
        push        ebx
        push        esi
        push        edi
        xor         eax, eax
        cpuid
        rdtsc
        mov         esi, eax
        mov         edi, edx
        xor         eax, eax
        cpuid
        mov         eax, esi
        mov         edx, edi
        pop         edi
        pop         esi
        pop         ebx
        ret
    }
}

float __declspec(naked) ceilf(float x)
{
    __asm
    {
        fld         dword ptr[esp+4]
        sub         esp, 4
        fnstcw      word ptr[esp]   // save CW
        movzx       eax, word ptr[esp]
        or          eax, 0x0b00     // round toward +INF, full precision
        mov         word ptr[esp+2], ax
        fldcw       word ptr[esp+2]
        frndint
        fldcw       word ptr[esp]
        add         esp, 4
        ret
    }
}

float __declspec(naked) truncf(float x)
{
    __asm
    {
        fld         dword ptr[esp+4]
        sub         esp, 4
        fnstcw      word ptr[esp]   // save CW
        movzx       eax, word ptr[esp]
        or          eax, 0x0f00     // round toward zero, full precision
        mov         word ptr[esp+2], ax
        fldcw       word ptr[esp+2]
        frndint
        fldcw       word ptr[esp]
        add         esp, 4
        ret
    }
}

float __declspec(naked) roundf(float x)
{
    __asm
    {
        fld         dword ptr[esp+4]
        frndint
        ret
    }
}

float __declspec(naked) log2f(float x)
{
    __asm
    {
        fld1
        fld         dword ptr[esp+4]
        fyl2x
        ret
    }
}

int __cdecl base2(int x)
{
    float q = float(x);
    return ((int &)q - 0x3f800000) >> 23;
}

void __cdecl Randomize()
{
    SYSTEMTIME st;
    GetSystemTime(&st);
    RandSeed = ((st.wHour * 60 + st.wMinute) * 60 + st.wSecond) * 1000 + st.wMilliseconds;
}

int __cdecl RandInt(int Range)
{
    int rs = RandSeed;
    int ri;
    __asm
    {
        mov     eax, [Range]
        imul    edx, [rs], 0x08088405
        add     edx, 1
        mov     [rs], edx
        mul     edx
        mov     [ri], edx
    }
    RandSeed = rs;
    return ri;
}

int __cdecl RandomRange(int nFrom, int nTo)
{
    return nFrom + RandInt(nTo - nFrom);
}

void __cdecl FillRandom(DWORD* buf, DWORD len, DWORD minVal, DWORD maxVal)
{
    DWORD l = len >> 2;
    for (DWORD i = 0; i < l; ++i)
    {
        int r0 = RANDOM_RANGE(minVal, maxVal);
        int r1 = RANDOM_RANGE(minVal, maxVal);
        int r2 = RANDOM_RANGE(minVal, maxVal);
        int r3 = RANDOM_RANGE(minVal, maxVal);
        buf[i] = DWORD(r0 | (r1 << 8) | (r2 << 16) | (r3 << 24));
    }
}