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public abstract Assign ( |
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| a | 割り当てたい値の入ったビットフィールド。 | |
| return | void | |
/// <summary>
/// Binary → BCD 変換
/// </summary>
/// <param name="bin">変換元</param>
/// <param name="overflow">オーバーフローが起きたらtrueにセットされる。</param>
/// <returns>変換結果</returns>
public static BitField BinToBcd(BitField bin, out bool overflow)
{
BitField bcd = BitField.Concat(BitField.Create(30, 0, 0), bin);
overflow = false;
for (int i = 0; i < 30; ++i)
{
BitField a0 = BinToBcdAddIn(bcd[61, 58]);
BitField a1 = BinToBcdAddIn(bcd[57, 54]);
BitField a2 = BinToBcdAddIn(bcd[53, 50]);
BitField a3 = BinToBcdAddIn(bcd[49, 46]);
BitField a4 = BinToBcdAddIn(bcd[45, 42]);
BitField a5 = BinToBcdAddIn(bcd[41, 38]);
BitField a6 = BinToBcdAddIn(bcd[37, 34]);
BitField a7 = BinToBcdAddIn(bcd[33, 30]);
BitField add_in = BitField.Concat(a0, a1, a2, a3, a4, a5, a6, a7);
BitField add_out = bcd[61, 30] + add_in;
bcd.Assign(BitField.Concat(add_out, bcd[29, 0], BitField.Create(0, 0, 0)));
overflow |= add_out[add_out.Msb];
}
return(bcd[61, 30]);
}
/// <summary>
/// 符号反転器。
/// </summary>
/// <param name="a">オペランド</param>
/// <returns>演算結果</returns>
public static BitField Negate(BitField a)
{
BitField tmp = BitField.Create(a.Msb, a.Lsb);
tmp.Assign(~a.Value + 1);
return(tmp);
}
/// <summary>
/// 乗算器。
/// </summary>
/// <param name="a">オペランド1</param>
/// <param name="b">オペランド2</param>
/// <returns>演算結果</returns>
public static BitField Mul(BitField a, BitField b)
{
bool sgn = a[a.Msb] ^ b[b.Msb];
BitField p = BitField.Create(63, 0);
BitField q = BitField.Create(31, 0);
if (a[a.Msb])
{
a = Negate(a);
}
if (b[b.Msb])
{
b = Negate(b);
}
p.Assign(BitField.Concat(BitField.Create(31, 0, 0), a));
q.Assign(b);
for (int i = 0; i < 32; ++i)
{
BitField addin1, addin2, addout;
addin1 = p[63, 32];
addin2 = q;
addout = addin1 + addin2;
if (p[0])
{
p.Assign(BitField.Concat(BitField.Create(0, 0, 0), addout, p[31, 1]));
}
else
{
p.Assign(BitField.Concat(BitField.Create(0, 0, 0), p[63, 1]));
}
}
if (sgn)
{
p = Negate(p);
}
return(p);
}
/// <summary>
/// 乗除算器。
/// </summary>
/// <param name="a">オペランド1</param>
/// <param name="b">オペランド2</param>
/// <param name="mul">true のとき乗算、 false のとき除算</param>
/// <returns>演算結果(乗算の場合、下位32ビットに商、上位32ビットに剰余)</returns>
public static BitField MulDiv(BitField a, BitField b, bool mul)
{
bool sgn = a[a.Msb] ^ b[b.Msb];
BitField p = BitField.Create(63, 0);
BitField q = BitField.Create(31, 0);
if (a[a.Msb])
{
a = Negate(a);
}
if (b[b.Msb])
{
b = Negate(b);
}
p.Assign(BitField.Concat(BitField.Create(31, 0, 0), a));
q.Assign(b);
for (int i = 0; i < 32; ++i)
{
BitField addin1, addin2, addout;
addin1 = mul ? p[63, 32] : p[62, 31];
addin2 = mul | p[63] ? q : Negate(q);
addout = addin1 + addin2;
if (mul)
{
if (p[0])
{
p.Assign(BitField.Concat(BitField.Create(0, 0, 0), addout, p[31, 1]));
}
else
{
p.Assign(BitField.Concat(BitField.Create(0, 0, 0), p[63, 1]));
}
}
else
{
p.Assign(BitField.Concat(addout, p[30, 0], ~addout[addout.Msb]));
}
}
if (!mul & !p[0])
{
BitField tmp = q + p[63, 32];
p.Assign(BitField.Concat(tmp, p[31, 0]));
}
if (sgn)
{
p = Negate(p);
}
return(p);
}
/// <summary>
/// BCD → Binary 変換
/// </summary>
/// <param name="bcd">変換元</param>
/// <returns>変換結果</returns>
public static BitField BcdToBin(BitField bcd)
{
BitField bin = BitField.Concat(BitField.Create(0, 0, 0), bcd, BitField.Create(29, 0, 0));
for (int i = 0; i < 30; ++i)
{
BitField a0 = BcdToBinAddIn(bin[62, 59]);
BitField a1 = BcdToBinAddIn(bin[58, 55]);
BitField a2 = BcdToBinAddIn(bin[54, 51]);
BitField a3 = BcdToBinAddIn(bin[50, 47]);
BitField a4 = BcdToBinAddIn(bin[46, 43]);
BitField a5 = BcdToBinAddIn(bin[42, 39]);
BitField a6 = BcdToBinAddIn(bin[38, 35]);
BitField a7 = BcdToBinAddIn(bin[34, 31]);
BitField add_in = BitField.Concat(a0, a1, a2, a3, a4, a5, a6, a7);
BitField add_out = bin[62, 31] + add_in + BitField.Create(31, 0, 1);
bin.Assign(BitField.Concat(BitField.Create(0, 0, 0), add_out, bin[30, 1]));
}
return(bin[31, 0]);
}
