From 2ecf62e06e3940c4cd2ed5e544b39ab04e93838d Mon Sep 17 00:00:00 2001
From: Lokathor <zefria@gmail.com>
Date: Sat, 22 Oct 2022 20:12:49 -0600
Subject: [PATCH] i think the debug finally works right?

---
 examples/hello.rs | 13 +++++++++
 src/fixed.rs      | 67 +++++++++++++++++++++++++++++++++++++++++++----
 2 files changed, 75 insertions(+), 5 deletions(-)

diff --git a/examples/hello.rs b/examples/hello.rs
index bdeace5..9a0a1e4 100644
--- a/examples/hello.rs
+++ b/examples/hello.rs
@@ -59,6 +59,19 @@ extern "C" fn main() -> ! {
 
   if let Ok(mut logger) = MgbaBufferedLogger::try_new(MgbaMessageLevel::Debug) {
     writeln!(logger, "hello!").ok();
+
+    let fx_u: Fixed<u32, 8> =
+      Fixed::<u32, 8>::wrapping_from(7) + Fixed::<u32, 8>::from_raw(12);
+    writeln!(logger, "fixed unsigned: {fx_u:?}").ok();
+
+    let fx_i1: Fixed<i32, 8> =
+      Fixed::<i32, 8>::wrapping_from(8) + Fixed::<i32, 8>::from_raw(15);
+    writeln!(logger, "fixed signed positive: {fx_i1:?}").ok();
+
+    let fx_i2: Fixed<i32, 8> = Fixed::<i32, 8>::wrapping_from(0)
+      - Fixed::<i32, 8>::wrapping_from(3)
+      - Fixed::<i32, 8>::from_raw(17);
+    writeln!(logger, "fixed signed negative: {fx_i2:?}").ok();
   }
 
   {
diff --git a/src/fixed.rs b/src/fixed.rs
index 9165b8a..4906e01 100644
--- a/src/fixed.rs
+++ b/src/fixed.rs
@@ -25,7 +25,7 @@ pub type i32fx8 = Fixed<i32, 8>;
 ///   should be *less than* the number of bits in the integer's type. Multiply
 ///   and divide ops need to shift the value by `B`, and so if `B` is greater
 ///   than or equal to the integer's size the op will panic.
-#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[derive(Default, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
 #[repr(transparent)]
 pub struct Fixed<I, const B: u32>(I);
 
@@ -205,7 +205,7 @@ impl_common_fixed_ops!(u16);
 impl_common_fixed_ops!(u32);
 
 macro_rules! impl_signed_fixed_ops {
-  ($t:ty) => {
+  ($t:ty, $unsigned:ty) => {
     impl<const B: u32> Fixed<$t, B> {
       /// Negate.
       #[inline]
@@ -214,6 +214,13 @@ macro_rules! impl_signed_fixed_ops {
         Self(-self.0)
       }
 
+      /// If the number is negative or not.
+      #[inline]
+      #[must_use]
+      pub const fn is_negative(self) -> bool {
+        self.0 < 0
+      }
+
       /// Multiply.
       #[inline]
       #[must_use]
@@ -230,13 +237,41 @@ macro_rules! impl_signed_fixed_ops {
         let d = m / (rhs.0 as i32);
         Self(d as $t)
       }
+
+      /// Fractional part of the value.
+      #[inline]
+      #[must_use]
+      pub const fn fract(self) -> Self {
+        let frac_mask = (<$unsigned>::MAX >> (<$t>::BITS - B));
+        Self((self.0.unsigned_abs() & frac_mask) as $t)
+      }
+
+      /// Whole part of the value.
+      #[inline]
+      #[must_use]
+      pub const fn trunc(self) -> Self {
+        Self(((self.0.unsigned_abs() >> B) << B) as $t)
+      }
     }
     impl_trait_op_unit!($t, Neg, neg);
+    impl<const B: u32> core::fmt::Debug for Fixed<$t, B> {
+      fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
+        let whole: $t = self.trunc().into_raw() >> B;
+        let fract: $t = self.fract().into_raw();
+        let divisor: $t = 1 << B;
+        if self.is_negative() {
+          let whole = whole.unsigned_abs();
+          write!(f, "-({whole}+{fract}/{divisor})")
+        } else {
+          write!(f, "{whole}+{fract}/{divisor}")
+        }
+      }
+    }
   };
 }
-impl_signed_fixed_ops!(i8);
-impl_signed_fixed_ops!(i16);
-impl_signed_fixed_ops!(i32);
+impl_signed_fixed_ops!(i8, u8);
+impl_signed_fixed_ops!(i16, u16);
+impl_signed_fixed_ops!(i32, u32);
 
 macro_rules! impl_unsigned_fixed_ops {
   ($t:ty) => {
@@ -257,6 +292,28 @@ macro_rules! impl_unsigned_fixed_ops {
         let d = m / (rhs.0 as u32);
         Self(d as $t)
       }
+
+      /// Fractional part of the value.
+      #[inline]
+      #[must_use]
+      pub const fn fract(self) -> Self {
+        Self(self.0 & (<$t>::MAX >> (<$t>::BITS - B)))
+      }
+
+      /// Whole part of the value.
+      #[inline]
+      #[must_use]
+      pub const fn trunc(self) -> Self {
+        Self(self.0 & (<$t>::MAX << B))
+      }
+    }
+    impl<const B: u32> core::fmt::Debug for Fixed<$t, B> {
+      fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
+        let whole: $t = self.trunc().into_raw() >> B;
+        let fract: $t = self.fract().into_raw();
+        let divisor: $t = 1 << B;
+        write!(f, "{whole}+{fract}/{divisor}")
+      }
     }
   };
 }