Use standard binary multiple unit symbols for game size display.

Use integer math for the calculation as we cannot rely on floats for something as important as game size display!

Source/Core/Common/Src/MathUtil.h

@@ -152,6 +152,28 @@ float MathFloatVectorSum(const std::vector<float>&);
 #define ROUND_UP(x, a)		(((x) + (a) - 1) & ~((a) - 1))
 #define ROUND_DOWN(x, a)	((x) & ~((a) - 1))
 
+template <typename T>
+T Log2(T val)
+{
+#if defined(_M_X64)
+	T result;
+	asm
+	(
+		"bsr %1, %0"
+		: "=r"(result)
+		: "r"(val)
+	);
+	return result;
+#else
+	T result = -1;
+	while (val != 0)
+	{
+		val >>= 1;
+		++result;
+	}
+	return result;
+#endif
+}
 
 // Tiny matrix/vector library.
 // Used for things like Free-Look in the gfx backend.

Source/Core/DolphinWX/Src/GameListCtrl.cpp

@@ -35,6 +35,7 @@
 #include "CDUtils.h"
 #include "WxUtils.h"
 #include "Main.h"
+#include "MathUtil.h"
 
 #include "../resources/Flag_Europe.xpm"
 #include "../resources/Flag_Germany.xpm"
@@ -380,26 +381,18 @@ void CGameListCtrl::Update()
 	SetFocus();
 }
 
-wxString NiceSizeFormat(s64 _size)
+wxString NiceSizeFormat(u64 _size)
 {
-	const char* sizes[] = {"b", "KB", "MB", "GB", "TB", "PB", "EB"};
-	int s = 0;
-	int frac = 0;
-
-	while (_size > (s64)1024)
-	{
-		s++;
-		frac   = (int)_size & 1023;
-		_size /= (s64)1024;
-	}
-
-	float f = (float)_size + ((float)frac / 1024.0f);
+	const char* const unit_symbols[] = {"B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB", "ZiB", "YiB"};
+
+	auto const unit = Log2(std::max<u64>(_size, 1)) / 10;
+	auto const unit_size = (1 << (unit * 10));
+
+	// ugly rounding integer math
+	auto const value = (_size + unit_size / 2) / unit_size;
+	auto const frac = (_size % unit_size * 10 + unit_size / 2) / unit_size % 10;
 
-	wxString NiceString;
-	char tempstr[32];
-	sprintf(tempstr,"%3.1f %s", f, sizes[s]);
-	NiceString = StrToWxStr(tempstr);
-	return(NiceString);
+	return StrToWxStr(StringFromFormat("%llu.%llu %s", value, frac, unit_symbols[unit]));
 }
 
 void CGameListCtrl::InsertItemInReportView(long _Index)