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76 lines
2.8 KiB
Rust
76 lines
2.8 KiB
Rust
//! Common match utils
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use super::errors::NumberOutOfRange;
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macro_rules! floating_fixed_convert {
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($f_to_q:ident, $q_to_f:ident, $unsigned_bin_typ:ty, $signed_bin_typ:ty, $float_ty:ty, $offset:literal, $min_positive:literal) => {
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/// convert float point to fixed point format
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pub fn $f_to_q(value: $float_ty) -> Result<$unsigned_bin_typ, NumberOutOfRange> {
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const MIN_POSITIVE: $float_ty = unsafe { core::mem::transmute($min_positive) };
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if value < -1.0 {
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return Err(NumberOutOfRange::BelowLowerBound)
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}
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if value > 1.0 {
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return Err(NumberOutOfRange::AboveUpperBound)
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}
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let value = if 1.0 - MIN_POSITIVE < value && value <= 1.0 {
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// make a exception for value between (1.0^{-x} , 1.0] float point,
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// convert it to max representable value of q1.x format
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(1.0 as $float_ty) - MIN_POSITIVE
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} else {
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value
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};
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// It's necessary to cast the float value to signed integer, before convert it to a unsigned value.
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// Since value from register is actually a "signed value", a "as" cast will keep original binary format but mark it as a unsigned value for register writing.
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// see https://doc.rust-lang.org/reference/expressions/operator-expr.html#numeric-cast
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Ok((value * ((1 as $unsigned_bin_typ << $offset) as $float_ty)) as $signed_bin_typ as $unsigned_bin_typ)
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}
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#[inline(always)]
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/// convert fixed point to float point format
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pub fn $q_to_f(value: $unsigned_bin_typ) -> $float_ty {
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// It's necessary to cast the unsigned integer to signed integer, before convert it to a float value.
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// Since value from register is actually a "signed value", a "as" cast will keep original binary format but mark it as a signed value.
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// see https://doc.rust-lang.org/reference/expressions/operator-expr.html#numeric-cast
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(value as $signed_bin_typ as $float_ty) / ((1 as $unsigned_bin_typ << $offset) as $float_ty)
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}
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};
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}
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floating_fixed_convert!(
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f64_to_q1_31,
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q1_31_to_f64,
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u32,
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i32,
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f64,
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31,
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0x3E00_0000_0000_0000u64 // binary form of 1f64^(-31)
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);
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floating_fixed_convert!(
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f32_to_q1_15,
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q1_15_to_f32,
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u16,
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i16,
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f32,
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15,
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0x3800_0000u32 // binary form of 1f32^(-15)
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);
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#[inline(always)]
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pub(crate) fn f32_args_to_u32(arg1: f32, arg2: f32) -> Result<u32, NumberOutOfRange> {
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Ok(f32_to_q1_15(arg1)? as u32 + ((f32_to_q1_15(arg2)? as u32) << 16))
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}
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#[inline(always)]
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pub(crate) fn u32_to_f32_res(reg_value: u32) -> (f32, f32) {
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let res1 = q1_15_to_f32((reg_value & ((1u32 << 16) - 1)) as u16);
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let res2 = q1_15_to_f32((reg_value >> 16) as u16);
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(res1, res2)
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}
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