added basic fixed point

.gitignore

@@ -14,3 +14,9 @@ Cargo.lock
 # MSVC Windows builds of rustc generate these, which store debugging information
 *.pdb
 
+
+
+# Added by cargo
+
+/target
+/Cargo.lock

.idea/.gitignore

@@ -0,0 +1,8 @@
+# Default ignored files
+/shelf/
+/workspace.xml
+# Editor-based HTTP Client requests
+/httpRequests/
+# Datasource local storage ignored files
+/dataSources/
+/dataSources.local.xml

.idea/misc.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectRootManager">
+    <output url="file://$PROJECT_DIR$/out" />
+  </component>
+</project>

.idea/modules.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/.idea/staticdot.iml" filepath="$PROJECT_DIR$/.idea/staticdot.iml" />
+    </modules>
+  </component>
+</project>

.idea/staticdot.iml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+      <excludeFolder url="file://$MODULE_DIR$/target" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>

.idea/vcs.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="" vcs="Git" />
+  </component>
+</project>

Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "staticdot"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

src/lib.rs

@@ -0,0 +1,87 @@
+use std::ops;
+use std::ops::{Add, BitAnd, Div, Mul, Shl, Shr, Sub};
+
+const INTEGER_BITS: i32 = 8;
+const FRACTION_BITS: i32 = 24;
+/// in oder to create the fraction bits mask we first fill all bits with 1 by initializing it with -1
+/// then we reinterpret the -1 as unsigned and shift it to the left. We need to do this in order to
+/// avoid arithmetic shifts
+const FRACTION_MASK: i32 = (-1i32 as u32 >> INTEGER_BITS) as i32;
+
+#[derive(Copy, Clone)]
+pub struct Fixed32(i32);
+
+impl From<i32> for Fixed32 {
+    fn from(value: i32) -> Self {
+        Fixed32(value.shl(FRACTION_BITS))
+    }
+}
+
+impl From<f32> for Fixed32 {
+    fn from(value: f32) -> Self {
+        let integral = (value as i32).shl(FRACTION_BITS);
+        let fraction = (value.fract() * 1.shl(FRACTION_BITS) as f32) as i32;
+        Fixed32(integral | fraction)
+    }
+}
+
+impl Into<i32> for Fixed32 {
+    fn into(self) -> i32 {
+        self.0.shr(FRACTION_BITS)
+    }
+}
+
+impl Into<f32> for Fixed32 {
+    fn into(self) -> f32 {
+        let integral = self.0.shr(FRACTION_BITS) as f32;
+        let fraction = self.0.bitand(FRACTION_MASK) as f32 / 1.shl(FRACTION_BITS) as f32;
+        integral + fraction
+    }
+}
+
+impl Add<Fixed32> for Fixed32 {
+    type Output = Fixed32;
+
+    fn add(self, rhs: Fixed32) -> Self::Output {
+        Fixed32(self.0 + rhs.0)
+    }
+}
+
+impl Sub<Fixed32> for Fixed32 {
+    type Output = Fixed32;
+
+    fn sub(self, rhs: Fixed32) -> Self::Output {
+        Fixed32(self.0 - rhs.0)
+    }
+}
+
+impl Mul<Fixed32> for Fixed32 {
+    type Output = Fixed32;
+
+    fn mul(self, rhs: Fixed32) -> Self::Output {
+        Fixed32(self.0.shr(FRACTION_BITS / 2) * rhs.0.shr(FRACTION_BITS / 2))
+    }
+}
+
+impl Div<Fixed32> for Fixed32 {
+    type Output = Fixed32;
+
+    fn div(self, rhs: Fixed32) -> Self::Output {
+        Fixed32((self.0 / rhs.0.shr(FRACTION_BITS / 2)).shl(FRACTION_BITS / 2))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test() {
+        let a = Fixed32::from(9);
+        let b = Fixed32::from(3);
+
+        let c = a * a / b;
+
+        println!("{}", Into::<f32>::into(c));
+    }
+}