alex/agb
1
0
Fork 0
mirror of https://github.com/italicsjenga/agb.git synced 2025-01-04 06:01:35 +11:00
Code Issues Packages Projects Releases Wiki Activity

upcast multiply

Browse source
This commit is contained in:
Corwin 2023-05-30 22:21:12 +01:00
parent da5aed83e3
commit 9fa8f75202
No known key found for this signature in database
1 changed files with 14 additions and 10 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

24
agb-fixnum/src/lib.rs
View file

@ -79,6 +79,8 @@ pub trait FixedWidthUnsignedInteger:
fn ten() -> Self; fn ten() -> Self;
/// Converts an i32 to it's own representation, panics on failure /// Converts an i32 to it's own representation, panics on failure
fn from_as_i32(v: i32) -> Self; fn from_as_i32(v: i32) -> Self;
/// Returns (a * b) >> N
fn upcast_multiply(a: Self, b: Self, n: usize) -> Self;
} }
/// Trait for an integer that includes negation /// Trait for an integer that includes negation
@ -89,7 +91,7 @@ pub trait FixedWidthSignedInteger: FixedWidthUnsignedInteger + Neg<Output = Self
} }
macro_rules! fixed_width_unsigned_integer_impl { macro_rules! fixed_width_unsigned_integer_impl {
($T: ty) => { ($T: ty, $Upcast: ty) => {
impl FixedWidthUnsignedInteger for $T { impl FixedWidthUnsignedInteger for $T {
#[inline(always)] #[inline(always)]
fn zero() -> Self { fn zero() -> Self {
@ -107,6 +109,10 @@ macro_rules! fixed_width_unsigned_integer_impl {
fn from_as_i32(v: i32) -> Self { fn from_as_i32(v: i32) -> Self {
v as $T v as $T
} }
#[inline(always)]
fn upcast_multiply(a: Self, b: Self, n: usize) -> Self {
(((a as $Upcast) * (b as $Upcast)) >> n) as $T
}
} }
}; };
} }
@ -122,12 +128,12 @@ macro_rules! fixed_width_signed_integer_impl {
}; };
} }
fixed_width_unsigned_integer_impl!(u8); fixed_width_unsigned_integer_impl!(u8, u32);
fixed_width_unsigned_integer_impl!(i16); fixed_width_unsigned_integer_impl!(i16, i32);
fixed_width_unsigned_integer_impl!(u16); fixed_width_unsigned_integer_impl!(u16, u32);
fixed_width_unsigned_integer_impl!(i32); fixed_width_unsigned_integer_impl!(i32, i64);
fixed_width_unsigned_integer_impl!(u32); fixed_width_unsigned_integer_impl!(u32, u64);
fixed_width_unsigned_integer_impl!(usize); fixed_width_unsigned_integer_impl!(usize, u64);
fixed_width_signed_integer_impl!(i16); fixed_width_signed_integer_impl!(i16);
fixed_width_signed_integer_impl!(i32); fixed_width_signed_integer_impl!(i32);
@ -204,9 +210,7 @@ where
{ {
type Output = Self; type Output = Self;
fn mul(self, rhs: Num<I, N>) -> Self::Output { fn mul(self, rhs: Num<I, N>) -> Self::Output {
Num(((self.floor() * rhs.floor()) << N) Num(I::upcast_multiply(self.0, rhs.0, N))
+ (self.floor() * rhs.frac() + rhs.floor() * self.frac())
+ ((self.frac() * rhs.frac()) >> N))
} }
} }