func (p *importer) ufloat() constant.Value { exp := p.int() x := constant.MakeFromBytes(p.bytes()) switch { case exp < 0: d := constant.Shift(constant.MakeInt64(1), token.SHL, uint(-exp)) x = constant.BinaryOp(x, token.QUO, d) case exp > 0: x = constant.Shift(x, token.SHL, uint(exp)) } return x }
func (p *importer) float() constant.Value { sign := p.int() if sign == 0 { return constant.MakeInt64(0) } exp := p.int() mant := []byte(p.string()) // big endian // remove leading 0's if any for len(mant) > 0 && mant[0] == 0 { mant = mant[1:] } // convert to little endian // TODO(gri) go/constant should have a more direct conversion function // (e.g., once it supports a big.Float based implementation) for i, j := 0, len(mant)-1; i < j; i, j = i+1, j-1 { mant[i], mant[j] = mant[j], mant[i] } // adjust exponent (constant.MakeFromBytes creates an integer value, // but mant represents the mantissa bits such that 0.5 <= mant < 1.0) exp -= len(mant) << 3 if len(mant) > 0 { for msd := mant[len(mant)-1]; msd&0x80 == 0; msd <<= 1 { exp++ } } x := constant.MakeFromBytes(mant) switch { case exp < 0: d := constant.Shift(constant.MakeInt64(1), token.SHL, uint(-exp)) x = constant.BinaryOp(x, token.QUO, d) case exp > 0: x = constant.Shift(x, token.SHL, uint(exp)) } if sign < 0 { x = constant.UnaryOp(token.SUB, x, 0) } return x }