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// Credit: taken from `rp-hal` (also licensed Apache+MIT)
// https://github.com/rp-rs/rp-hal/blob/main/rp2040-hal/src/float/add_sub.rs
use super::{Float, Int};
use crate::rom_data;
trait ROMAdd {
fn rom_add(self, b: Self) -> Self;
}
impl ROMAdd for f32 {
fn rom_add(self, b: Self) -> Self {
rom_data::float_funcs::fadd(self, b)
}
}
impl ROMAdd for f64 {
fn rom_add(self, b: Self) -> Self {
rom_data::double_funcs::dadd(self, b)
}
}
fn add<F: Float + ROMAdd>(a: F, b: F) -> F {
if a.is_not_finite() {
if b.is_not_finite() {
let class_a = a.repr() & (F::SIGNIFICAND_MASK | F::SIGN_MASK);
let class_b = b.repr() & (F::SIGNIFICAND_MASK | F::SIGN_MASK);
if class_a == F::Int::ZERO && class_b == F::Int::ZERO {
// inf + inf = inf
return a;
}
if class_a == F::SIGN_MASK && class_b == F::SIGN_MASK {
// -inf + (-inf) = -inf
return a;
}
// Sign mismatch, or either is NaN already
return F::NAN;
}
// [-]inf/NaN + X = [-]inf/NaN
return a;
}
if b.is_not_finite() {
// X + [-]inf/NaN = [-]inf/NaN
return b;
}
a.rom_add(b)
}
intrinsics! {
#[alias = __addsf3vfp]
#[aeabi = __aeabi_fadd]
extern "C" fn __addsf3(a: f32, b: f32) -> f32 {
add(a, b)
}
#[bootrom_v2]
#[alias = __adddf3vfp]
#[aeabi = __aeabi_dadd]
extern "C" fn __adddf3(a: f64, b: f64) -> f64 {
add(a, b)
}
// The ROM just implements subtraction the same way, so just do it here
// and save the work of implementing more complicated NaN/inf handling.
#[alias = __subsf3vfp]
#[aeabi = __aeabi_fsub]
extern "C" fn __subsf3(a: f32, b: f32) -> f32 {
add(a, -b)
}
#[bootrom_v2]
#[alias = __subdf3vfp]
#[aeabi = __aeabi_dsub]
extern "C" fn __subdf3(a: f64, b: f64) -> f64 {
add(a, -b)
}
extern "aapcs" fn __aeabi_frsub(a: f32, b: f32) -> f32 {
add(b, -a)
}
#[bootrom_v2]
extern "aapcs" fn __aeabi_drsub(a: f64, b: f64) -> f64 {
add(b, -a)
}
}
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