diff --git a/src/float/conv.rs b/src/float/conv.rs index f358a17..52fdf95 100644 --- a/src/float/conv.rs +++ b/src/float/conv.rs @@ -1,87 +1,83 @@ use float::Float; use int::{Int, CastInto}; -fn int_to_float(i: I) -> F where - F::Int: CastInto, - F::Int: CastInto, - I::UnsignedInt: CastInto, - u32: CastInto, -{ - if i == I::ZERO { - return F::ZERO; - } +macro_rules! int_to_float { + ($i:expr, $ity:ty, $fty:ty) => ({ + let i = $i; + if i == 0 { + return 0.0 + } - let two = I::UnsignedInt::ONE + I::UnsignedInt::ONE; - let four = two + two; - let mant_dig = F::SIGNIFICAND_BITS + 1; - let exponent_bias = F::EXPONENT_BIAS; + let mant_dig = <$fty>::SIGNIFICAND_BITS + 1; + let exponent_bias = <$fty>::EXPONENT_BIAS; - let n = I::BITS; - let (s, a) = i.extract_sign(); - let mut a = a; + let n = <$ity>::BITS; + let (s, a) = i.extract_sign(); + let mut a = a; - // number of significant digits - let sd = n - a.leading_zeros(); + // number of significant digits + let sd = n - a.leading_zeros(); - // exponent - let mut e = sd - 1; + // exponent + let mut e = sd - 1; - if I::BITS < mant_dig { - return F::from_parts(s, - (e + exponent_bias).cast(), - a.cast() << (mant_dig - e - 1)); - } + if <$ity>::BITS < mant_dig { + return <$fty>::from_parts(s, + (e + exponent_bias) as <$fty as Float>::Int, + (a as <$fty as Float>::Int) << (mant_dig - e - 1)) + } - a = if sd > mant_dig { - /* start: 0000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQxxxxxxxxxxxxxxxxxx - * finish: 000000000000000000000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQR - * 12345678901234567890123456 - * 1 = msb 1 bit - * P = bit MANT_DIG-1 bits to the right of 1 - * Q = bit MANT_DIG bits to the right of 1 - * R = "or" of all bits to the right of Q - */ - let mant_dig_plus_one = mant_dig + 1; - let mant_dig_plus_two = mant_dig + 2; - a = if sd == mant_dig_plus_one { - a << 1 - } else if sd == mant_dig_plus_two { + a = if sd > mant_dig { + /* start: 0000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQxxxxxxxxxxxxxxxxxx + * finish: 000000000000000000000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQR + * 12345678901234567890123456 + * 1 = msb 1 bit + * P = bit MANT_DIG-1 bits to the right of 1 + * Q = bit MANT_DIG bits to the right of 1 + * R = "or" of all bits to the right of Q + */ + let mant_dig_plus_one = mant_dig + 1; + let mant_dig_plus_two = mant_dig + 2; + a = if sd == mant_dig_plus_one { + a << 1 + } else if sd == mant_dig_plus_two { + a + } else { + (a >> (sd - mant_dig_plus_two)) as <$ity as Int>::UnsignedInt | + ((a & <$ity as Int>::UnsignedInt::max_value()).wrapping_shl((n + mant_dig_plus_two) - sd) != 0) as <$ity as Int>::UnsignedInt + }; + + /* finish: */ + a |= ((a & 4) != 0) as <$ity as Int>::UnsignedInt; /* Or P into R */ + a += 1; /* round - this step may add a significant bit */ + a >>= 2; /* dump Q and R */ + + /* a is now rounded to mant_dig or mant_dig+1 bits */ + if (a & (1 << mant_dig)) != 0 { + a >>= 1; e += 1; + } a + /* a is now rounded to mant_dig bits */ } else { - (a >> (sd - mant_dig_plus_two)) | - Int::from_bool((a & I::UnsignedInt::max_value()).wrapping_shl((n + mant_dig_plus_two) - sd) != Int::ZERO) + a.wrapping_shl(mant_dig - sd) + /* a is now rounded to mant_dig bits */ }; - /* finish: */ - a |= Int::from_bool((a & four) != I::UnsignedInt::ZERO); /* Or P into R */ - a += Int::ONE; /* round - this step may add a significant bit */ - a >>= 2; /* dump Q and R */ - - /* a is now rounded to mant_dig or mant_dig+1 bits */ - if (a & (I::UnsignedInt::ONE << mant_dig)) != Int::ZERO { - a >>= 1; e += 1; - } - a - /* a is now rounded to mant_dig bits */ - } else { - a.wrapping_shl(mant_dig - sd) - /* a is now rounded to mant_dig bits */ - }; - - F::from_parts(s, - (e + exponent_bias).cast(), - a.cast()) + <$fty>::from_parts(s, + (e + exponent_bias) as <$fty as Float>::Int, + a as <$fty as Float>::Int) + }) } intrinsics! { #[arm_aeabi_alias = __aeabi_i2f] pub extern "C" fn __floatsisf(i: i32) -> f32 { - int_to_float(i) + int_to_float!(i, i32, f32) } #[arm_aeabi_alias = __aeabi_i2d] pub extern "C" fn __floatsidf(i: i32) -> f64 { - int_to_float(i) + int_to_float!(i, i32, f64) } #[use_c_shim_if(all(target_arch = "x86", not(target_env = "msvc")))] @@ -92,28 +88,28 @@ intrinsics! { if cfg!(target_arch = "x86_64") { i as f64 } else { - int_to_float(i) + int_to_float!(i, i64, f64) } } #[unadjusted_on_win64] pub extern "C" fn __floattisf(i: i128) -> f32 { - int_to_float(i) + int_to_float!(i, i128, f32) } #[unadjusted_on_win64] pub extern "C" fn __floattidf(i: i128) -> f64 { - int_to_float(i) + int_to_float!(i, i128, f64) } #[arm_aeabi_alias = __aeabi_ui2f] pub extern "C" fn __floatunsisf(i: u32) -> f32 { - int_to_float(i) + int_to_float!(i, u32, f32) } #[arm_aeabi_alias = __aeabi_ui2d] pub extern "C" fn __floatunsidf(i: u32) -> f64 { - int_to_float(i) + int_to_float!(i, u32, f64) } #[use_c_shim_if(all(not(target_env = "msvc"), @@ -121,17 +117,17 @@ intrinsics! { all(not(windows), target_arch = "x86_64"))))] #[arm_aeabi_alias = __aeabi_ul2d] pub extern "C" fn __floatundidf(i: u64) -> f64 { - int_to_float(i) + int_to_float!(i, u64, f64) } #[unadjusted_on_win64] pub extern "C" fn __floatuntisf(i: u128) -> f32 { - int_to_float(i) + int_to_float!(i, u128, f32) } #[unadjusted_on_win64] pub extern "C" fn __floatuntidf(i: u128) -> f64 { - int_to_float(i) + int_to_float!(i, u128, f64) } }