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@@ -1,90 +1,88 @@
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use float::Float;
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-use int::Int;
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-
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-macro_rules! int_to_float {
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- ($i:expr, $ity:ty, $fty:ty) => {{
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- let i = $i;
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- if i == 0 {
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- return 0.0;
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- }
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-
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- let mant_dig = <$fty>::SIGNIFICAND_BITS + 1;
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- let exponent_bias = <$fty>::EXPONENT_BIAS;
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-
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- let n = <$ity as Int>::BITS;
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- let (s, a) = i.extract_sign();
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- let mut a = a;
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-
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- // number of significant digits
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- let sd = n - a.leading_zeros();
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-
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- // exponent
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- let mut e = sd - 1;
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+use int::{CastInto, Int};
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+
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+fn int_to_float<I: Int, F: Float>(i: I) -> F
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+where
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+ F::Int: CastInto<u32>,
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+ F::Int: CastInto<I>,
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+ I::UnsignedInt: CastInto<F::Int>,
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+ u32: CastInto<F::Int>,
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+{
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+ if i == I::ZERO {
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+ return F::ZERO;
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+ }
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- if <$ity as Int>::BITS < mant_dig {
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- return <$fty>::from_parts(
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- s,
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- (e + exponent_bias) as <$fty as Float>::Int,
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- (a as <$fty as Float>::Int) << (mant_dig - e - 1),
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- );
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- }
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+ let two = I::UnsignedInt::ONE + I::UnsignedInt::ONE;
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+ let four = two + two;
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+ let sign = i < I::ZERO;
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+ let mut x = Int::abs_diff(i, I::ZERO);
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+
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+ // number of significant digits in the integer
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+ let i_sd = I::BITS - x.leading_zeros();
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+ // significant digits for the float, including implicit bit
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+ let f_sd = F::SIGNIFICAND_BITS + 1;
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+
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+ // exponent
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+ let mut exp = i_sd - 1;
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+
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+ if I::BITS < f_sd {
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+ return F::from_parts(
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+ sign,
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+ (exp + F::EXPONENT_BIAS).cast(),
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+ x.cast() << (f_sd - exp - 1),
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+ );
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+ }
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- a = if sd > mant_dig {
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- /* start: 0000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQxxxxxxxxxxxxxxxxxx
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- * finish: 000000000000000000000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQR
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- * 12345678901234567890123456
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- * 1 = msb 1 bit
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- * P = bit MANT_DIG-1 bits to the right of 1
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- * Q = bit MANT_DIG bits to the right of 1
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- * R = "or" of all bits to the right of Q
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- */
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- let mant_dig_plus_one = mant_dig + 1;
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- let mant_dig_plus_two = mant_dig + 2;
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- a = if sd == mant_dig_plus_one {
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- a << 1
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- } else if sd == mant_dig_plus_two {
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- a
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- } else {
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- (a >> (sd - mant_dig_plus_two)) as <$ity as Int>::UnsignedInt
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- | ((a & <$ity as Int>::UnsignedInt::max_value())
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- .wrapping_shl((n + mant_dig_plus_two) - sd)
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- != 0) as <$ity as Int>::UnsignedInt
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- };
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-
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- /* finish: */
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- a |= ((a & 4) != 0) as <$ity as Int>::UnsignedInt; /* Or P into R */
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- a += 1; /* round - this step may add a significant bit */
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- a >>= 2; /* dump Q and R */
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-
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- /* a is now rounded to mant_dig or mant_dig+1 bits */
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- if (a & (1 << mant_dig)) != 0 {
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- a >>= 1;
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- e += 1;
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- }
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- a
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- /* a is now rounded to mant_dig bits */
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+ x = if i_sd > f_sd {
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+ // start: 0000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQxxxxxxxxxxxxxxxxxx
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+ // finish: 000000000000000000000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQR
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+ // 12345678901234567890123456
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+ // 1 = the implicit bit
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+ // P = bit f_sd-1 bits to the right of 1
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+ // Q = bit f_sd bits to the right of 1
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+ // R = "or" of all bits to the right of Q
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+ let f_sd_add2 = f_sd + 2;
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+ x = if i_sd == (f_sd + 1) {
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+ x << 1
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+ } else if i_sd == f_sd_add2 {
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+ x
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} else {
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- a.wrapping_shl(mant_dig - sd)
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- /* a is now rounded to mant_dig bits */
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+ (x >> (i_sd - f_sd_add2))
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+ | Int::from_bool(
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+ (x & I::UnsignedInt::MAX).wrapping_shl((I::BITS + f_sd_add2) - i_sd)
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+ != Int::ZERO,
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+ )
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};
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- <$fty>::from_parts(
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- s,
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- (e + exponent_bias) as <$fty as Float>::Int,
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- a as <$fty as Float>::Int,
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- )
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- }};
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+ // R |= P
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+ x |= Int::from_bool((x & four) != I::UnsignedInt::ZERO);
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+ // round - this step may add a significant bit
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+ x += Int::ONE;
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+ // dump Q and R
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+ x >>= 2;
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+
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+ // a is now rounded to f_sd or f_sd+1 bits
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+ if (x & (I::UnsignedInt::ONE << f_sd)) != Int::ZERO {
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+ x >>= 1;
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+ exp += 1;
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+ }
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+ x
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+ } else {
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+ x.wrapping_shl(f_sd - i_sd)
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+ };
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+
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+ F::from_parts(sign, (exp + F::EXPONENT_BIAS).cast(), x.cast())
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}
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intrinsics! {
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#[arm_aeabi_alias = __aeabi_i2f]
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pub extern "C" fn __floatsisf(i: i32) -> f32 {
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- int_to_float!(i, i32, f32)
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+ int_to_float(i)
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}
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#[arm_aeabi_alias = __aeabi_i2d]
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pub extern "C" fn __floatsidf(i: i32) -> f64 {
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- int_to_float!(i, i32, f64)
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+ int_to_float(i)
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}
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#[maybe_use_optimized_c_shim]
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@@ -95,7 +93,7 @@ intrinsics! {
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if cfg!(target_arch = "x86_64") {
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i as f32
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} else {
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- int_to_float!(i, i64, f32)
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+ int_to_float(i)
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}
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}
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@@ -107,181 +105,172 @@ intrinsics! {
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if cfg!(target_arch = "x86_64") {
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i as f64
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} else {
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- int_to_float!(i, i64, f64)
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+ int_to_float(i)
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}
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}
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#[unadjusted_on_win64]
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pub extern "C" fn __floattisf(i: i128) -> f32 {
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- int_to_float!(i, i128, f32)
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+ int_to_float(i)
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}
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#[unadjusted_on_win64]
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pub extern "C" fn __floattidf(i: i128) -> f64 {
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- int_to_float!(i, i128, f64)
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+ int_to_float(i)
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}
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#[arm_aeabi_alias = __aeabi_ui2f]
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pub extern "C" fn __floatunsisf(i: u32) -> f32 {
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- int_to_float!(i, u32, f32)
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+ int_to_float(i)
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}
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#[arm_aeabi_alias = __aeabi_ui2d]
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pub extern "C" fn __floatunsidf(i: u32) -> f64 {
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- int_to_float!(i, u32, f64)
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+ int_to_float(i)
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}
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#[maybe_use_optimized_c_shim]
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#[arm_aeabi_alias = __aeabi_ul2f]
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pub extern "C" fn __floatundisf(i: u64) -> f32 {
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- int_to_float!(i, u64, f32)
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+ int_to_float(i)
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}
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#[maybe_use_optimized_c_shim]
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#[arm_aeabi_alias = __aeabi_ul2d]
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pub extern "C" fn __floatundidf(i: u64) -> f64 {
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- int_to_float!(i, u64, f64)
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+ int_to_float(i)
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}
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#[unadjusted_on_win64]
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pub extern "C" fn __floatuntisf(i: u128) -> f32 {
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- int_to_float!(i, u128, f32)
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+ int_to_float(i)
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}
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#[unadjusted_on_win64]
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pub extern "C" fn __floatuntidf(i: u128) -> f64 {
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- int_to_float!(i, u128, f64)
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+ int_to_float(i)
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}
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}
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-#[derive(PartialEq)]
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-enum Sign {
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- Positive,
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- Negative,
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-}
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+fn float_to_int<F: Float, I: Int>(f: F) -> I
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+where
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+ F::ExpInt: CastInto<u32>,
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+ u32: CastInto<F::ExpInt>,
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+ F::Int: CastInto<I>,
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+{
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+ // converting NaNs is UB, so we don't consider them
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+
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+ let sign = f.sign();
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+ let mut exp = f.exp();
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-macro_rules! float_to_int {
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- ($f:expr, $fty:ty, $ity:ty) => {{
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- let f = $f;
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- let fixint_min = <$ity>::min_value();
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- let fixint_max = <$ity>::max_value();
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- let fixint_bits = <$ity as Int>::BITS as usize;
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- let fixint_unsigned = fixint_min == 0;
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-
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- let sign_bit = <$fty>::SIGN_MASK;
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- let significand_bits = <$fty>::SIGNIFICAND_BITS as usize;
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- let exponent_bias = <$fty>::EXPONENT_BIAS as usize;
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- //let exponent_max = <$fty>::exponent_max() as usize;
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-
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- // Break a into sign, exponent, significand
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- let a_rep = <$fty>::repr(f);
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- let a_abs = a_rep & !sign_bit;
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-
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- // this is used to work around -1 not being available for unsigned
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- let sign = if (a_rep & sign_bit) == 0 {
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- Sign::Positive
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+ // if less than one or unsigned & negative
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+ if (exp < F::EXPONENT_BIAS.cast()) || (!I::SIGNED && sign) {
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+ return I::ZERO;
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+ }
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+ exp -= F::EXPONENT_BIAS.cast();
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+
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+ // If the value is too large for `I`, saturate.
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+ let bits: F::ExpInt = I::BITS.cast();
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+ let max = if I::SIGNED {
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+ bits - F::ExpInt::ONE
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+ } else {
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+ bits
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+ };
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+ if max <= exp {
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+ return if sign {
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+ // It happens that I::MIN is handled correctly
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+ I::MIN
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} else {
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- Sign::Negative
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+ I::MAX
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};
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- let mut exponent = (a_abs >> significand_bits) as usize;
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- let significand = (a_abs & <$fty>::SIGNIFICAND_MASK) | <$fty>::IMPLICIT_BIT;
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+ };
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- // if < 1 or unsigned & negative
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- if exponent < exponent_bias || fixint_unsigned && sign == Sign::Negative {
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- return 0;
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- }
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- exponent -= exponent_bias;
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-
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- // If the value is infinity, saturate.
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- // If the value is too large for the integer type, 0.
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- if exponent
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- >= (if fixint_unsigned {
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- fixint_bits
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- } else {
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- fixint_bits - 1
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- })
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- {
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- return if sign == Sign::Positive {
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- fixint_max
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- } else {
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- fixint_min
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- };
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- }
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- // If 0 <= exponent < significand_bits, right shift to get the result.
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- // Otherwise, shift left.
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- // (sign - 1) will never overflow as negative signs are already returned as 0 for unsigned
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- let r = if exponent < significand_bits {
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- (significand >> (significand_bits - exponent)) as $ity
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+ // `0 <= exp < max`
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+
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+ // If 0 <= exponent < F::SIGNIFICAND_BITS, right shift to get the result. Otherwise, shift left.
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+ let sig_bits: F::ExpInt = F::SIGNIFICAND_BITS.cast();
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+ // The larger integer has to be casted into, or else the shift overflows
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+ let r: I = if F::Int::BITS < I::BITS {
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+ let tmp: I = if exp < sig_bits {
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+ f.imp_frac().cast() >> (sig_bits - exp).cast()
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} else {
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- (significand as $ity) << (exponent - significand_bits)
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+ f.imp_frac().cast() << (exp - sig_bits).cast()
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};
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-
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- if sign == Sign::Negative {
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- (!r).wrapping_add(1)
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+ tmp
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+ } else {
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+ let tmp: F::Int = if exp < sig_bits {
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+ f.imp_frac() >> (sig_bits - exp).cast()
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} else {
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- r
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- }
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- }};
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+ f.imp_frac() << (exp - sig_bits).cast()
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+ };
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+ tmp.cast()
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+ };
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+
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+ if sign {
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+ r.wrapping_neg()
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+ } else {
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+ r
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+ }
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}
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intrinsics! {
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#[arm_aeabi_alias = __aeabi_f2iz]
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pub extern "C" fn __fixsfsi(f: f32) -> i32 {
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- float_to_int!(f, f32, i32)
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+ float_to_int(f)
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}
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#[arm_aeabi_alias = __aeabi_f2lz]
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pub extern "C" fn __fixsfdi(f: f32) -> i64 {
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- float_to_int!(f, f32, i64)
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+ float_to_int(f)
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}
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#[unadjusted_on_win64]
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pub extern "C" fn __fixsfti(f: f32) -> i128 {
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- float_to_int!(f, f32, i128)
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+ float_to_int(f)
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}
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#[arm_aeabi_alias = __aeabi_d2iz]
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pub extern "C" fn __fixdfsi(f: f64) -> i32 {
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- float_to_int!(f, f64, i32)
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+ float_to_int(f)
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}
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#[arm_aeabi_alias = __aeabi_d2lz]
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pub extern "C" fn __fixdfdi(f: f64) -> i64 {
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- float_to_int!(f, f64, i64)
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+ float_to_int(f)
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}
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#[unadjusted_on_win64]
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pub extern "C" fn __fixdfti(f: f64) -> i128 {
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- float_to_int!(f, f64, i128)
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+ float_to_int(f)
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}
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#[arm_aeabi_alias = __aeabi_f2uiz]
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pub extern "C" fn __fixunssfsi(f: f32) -> u32 {
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- float_to_int!(f, f32, u32)
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+ float_to_int(f)
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}
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#[arm_aeabi_alias = __aeabi_f2ulz]
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pub extern "C" fn __fixunssfdi(f: f32) -> u64 {
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- float_to_int!(f, f32, u64)
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+ float_to_int(f)
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}
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#[unadjusted_on_win64]
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pub extern "C" fn __fixunssfti(f: f32) -> u128 {
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- float_to_int!(f, f32, u128)
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+ float_to_int(f)
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}
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#[arm_aeabi_alias = __aeabi_d2uiz]
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pub extern "C" fn __fixunsdfsi(f: f64) -> u32 {
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- float_to_int!(f, f64, u32)
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+ float_to_int(f)
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}
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#[arm_aeabi_alias = __aeabi_d2ulz]
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pub extern "C" fn __fixunsdfdi(f: f64) -> u64 {
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- float_to_int!(f, f64, u64)
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+ float_to_int(f)
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}
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#[unadjusted_on_win64]
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pub extern "C" fn __fixunsdfti(f: f64) -> u128 {
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- float_to_int!(f, f64, u128)
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+ float_to_int(f)
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}
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}
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