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Tiny C Runtime Library

, 25 Mar 2007
Reduce code bloat for those simple utility programs by using a streamlined C runtime - now with Unicode support!
// math.cpp

// math functions

// 08/20/05 (mv)

#include <windows.h>
#include "libct.h"

BEGIN_EXTERN_C

static int lastrand;
int _fltused = 0;

int abs(int n)
{
	return (n>0)?n:-n;
}

void srand(unsigned int seed)
{
	lastrand = seed;
}

int rand()
{
	return (((lastrand = lastrand * 214013L + 2531011L) >> 16) & 0x7FFF);
}

__declspec(naked) void _CIacos()
{
	__asm
	{
		fld		st(0)
		fld		st(0)
		fmul
		fld1
		fsubr
		fsqrt
		fxch
		fpatan
		ret
	}
}

__declspec(naked) void _ftol2()
{
	__asm
	{
		push        ebp
		mov         ebp,esp
		sub         esp,20h
		and         esp,0FFFFFFF0h
		fld         st(0)
		fst         dword ptr [esp+18h]
		fistp       qword ptr [esp+10h]
		fild        qword ptr [esp+10h]
		mov         edx,dword ptr [esp+18h]
		mov         eax,dword ptr [esp+10h]
		test        eax,eax
		je          integer_QnaN_or_zero
	arg_is_not_integer_QnaN:
		fsubp       st(1),st
		test        edx,edx
		jns         positive
		fstp        dword ptr [esp]
		mov         ecx,dword ptr [esp]
		xor         ecx,80000000h
		add         ecx,7FFFFFFFh
		adc         eax,0
		mov         edx,dword ptr [esp+14h]
		adc         edx,0
		jmp         localexit
	positive:
		fstp        dword ptr [esp]
		mov         ecx,dword ptr [esp]
		add         ecx,7FFFFFFFh
		sbb         eax,0
		mov         edx,dword ptr [esp+14h]
		sbb         edx,0
		jmp         localexit
	integer_QnaN_or_zero:
		mov         edx,dword ptr [esp+14h]
		test        edx,7FFFFFFFh
		jne         arg_is_not_integer_QnaN
		fstp        dword ptr [esp+18h]
		fstp        dword ptr [esp+18h]
	localexit:
  		leave
  		ret
	}
}

END_EXTERN_C

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About the Author

Mike_V

United States United States
Mike_V is currently a student at UCLA.
 
After a few years on the Dark Side, he reformed and now chants "Death to VB." His computer-related interests include C++, C#, and ASP.NET (in C#, of course). He writes operating systems in C++ and assembler as a hobby.

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