/// <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>
/// バイナリ→BCD 変換の補正値求める。
/// </summary>
/// <param name="a">4ビットバイナリ</param>
/// <returns>補正値</returns>
static private BitField BinToBcdAddIn(BitField a)
{
return BitField.Create(3, 0, a.Value >= 5 ? 0x3UL : 0x0UL);
}
/// <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>
/// BCD →バイナリ変換の補正値求める。
/// </summary>
/// <param name="a">1桁(4ビット)BCD</param>
/// <returns>補正値</returns>
static private BitField BcdToBinAddIn(BitField a)
{
return BitField.Create(3, 0, a.Value >= 8 ? 0xCUL : 0xFUL);
}
/// <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>
/// 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];
}
/// <summary>
/// 値を割り当てる。
/// </summary>
/// <param name="a">割り当てたい値の入ったビットフィールド。</param>
/// <exception cref="BitFieldException">
/// this.Width != a.Width のとき発生。
/// </exception>
public override void Assign(BitField a)
{
if(a.Width != this.Width)
throw new BitFieldException("width don't match");
this.bf.Assign(this.msb, this.lsb, a);
}
/// <summary>
/// m〜l ビット目に値を割り当てる。
/// </summary>
/// <param name="m">MSB</param>
/// <param name="l">LSB</param>
/// <param name="a">割り当てたい値の入ったビットフィールド</param>
/// <exception cref="BitFieldException">
/// this.Sub(m, l).Width != a.Width のとき発生。
/// </exception>
public override void Assign(int m, int l, BitField a)
{
if(a.Width != m-l+1)
throw new BitFieldException("width don't match");
if(m < l || this.msb < m || this.lsb > l)
throw new BitFieldException("illegal range");
this.bf.Assign(m, l, a);
}
/// <summary>
/// bf の msb〜lsb 目。
/// </summary>
/// <param name="msb">MSB</param>
/// <param name="lsb">LSB</param>
/// <param name="bf">元となるビットフィールド</param>
public BitFieldSub(int msb, int lsb, BitField bf)
{
this.msb = msb;
this.lsb = lsb;
this.bf = bf;
}
/// <summary>
/// m〜l ビット目に値を割り当てる。
/// </summary>
/// <param name="m">MSB</param>
/// <param name="l">LSB</param>
/// <param name="a">割り当てたい値の入ったビットフィールド</param>
/// <exception cref="BitFieldException">
/// this.Sub(m, l).Width != a.Width のとき発生。
/// </exception>
public override void Assign(int m, int l, BitField a)
{
if(a.Width != m-l+1)
throw new BitFieldException("width don't match");
if(m < l || this.msb < m || this.lsb > l)
throw new BitFieldException("illegal range");
ulong val = a.Value;
ulong mask = this.GetMask(m, l);
val <<= l;
val &= mask;
this.n = val | (this.n & ~mask);
}
/// <summary>
/// 値を割り当てる。
/// </summary>
/// <param name="a">割り当てたい値の入ったビットフィールド。</param>
/// <exception cref="BitFieldException">
/// this.Width != a.Width のとき発生。
/// </exception>
public override void Assign(BitField a)
{
if(a.Width != this.Width)
throw new BitFieldException("width don't match");
ulong val = a.Value;
this.n = val << this.lsb;
}
/// <summary> /// m〜l ビット目に値を割り当てる。 /// </summary> /// <param name="m">MSB</param> /// <param name="l">LSB</param> /// <param name="a">割り当てたい値の入ったビットフィールド</param> /// <exception cref="BitFieldException"> /// this.Sub(m, l).Width != a.Width のとき発生。 /// </exception> public abstract void Assign(int m, int l, BitField a);
/// <summary> /// 値を割り当てる。 /// </summary> /// <param name="a">割り当てたい値の入ったビットフィールド。</param> /// <exception cref="BitFieldException"> /// this.Width != a.Width のとき発生。 /// </exception> public abstract void Assign(BitField a);
