From 999d9694f304b61cd07756d3582831db3dcef553 Mon Sep 17 00:00:00 2001
From: nerodesu017 <46645625+nerodesu017@users.noreply.github.com>
Date: Mon, 1 Jul 2024 15:53:53 +0300
Subject: [PATCH] feat + test: i32.div_u operation

---
 src/execution/mod.rs         | 19 +++++++++++
 src/validation/code.rs       |  7 ++++
 tests/arithmetic/division.rs | 62 ++++++++++++++++++++++++++++++++++++
 3 files changed, 88 insertions(+)

diff --git a/src/execution/mod.rs b/src/execution/mod.rs
index a2951faa..608ae29c 100644
--- a/src/execution/mod.rs
+++ b/src/execution/mod.rs
@@ -239,6 +239,25 @@ impl<'b> RuntimeInstance<'b> {
                     trace!("Instruction: i32.div_s [{divisor} {dividend}] -> [{res}]");
                     stack.push_value(res.into());
                 }
+                // i32.div_u: [i32 i32] -> [i32]
+                0x6E => {
+                    let dividend: i32 = stack.pop_value(ValType::NumType(NumType::I32)).into();
+                    let divisor: i32 = stack.pop_value(ValType::NumType(NumType::I32)).into();
+
+                    let dividend = dividend as u32;
+                    let divisor = divisor as u32;
+
+                    if dividend == 0 {
+                      return Err(crate::Error::RuntimeError(
+                        crate::core::error::RuntimeError::DivideBy0,
+                    ));
+                    }
+
+                    let res = (divisor / dividend) as i32;
+
+                    trace!("Instruction: i32.div_u [{divisor} {dividend}] -> [{res}]");
+                    stack.push_value(res.into());
+                }
                 other => {
                     trace!("Unknown instruction {other:#x}, skipping..");
                 }
diff --git a/src/validation/code.rs b/src/validation/code.rs
index 387a499d..7dcf5c3d 100644
--- a/src/validation/code.rs
+++ b/src/validation/code.rs
@@ -183,6 +183,13 @@ fn read_instructions(
 
                 value_stack.push_back(ValType::NumType(NumType::I32));
             }
+            // i32.div_u: [i32 i32] -> [i32]
+            0x6E => {
+                assert_pop_value_stack(value_stack, ValType::NumType(NumType::I32))?;
+                assert_pop_value_stack(value_stack, ValType::NumType(NumType::I32))?;
+
+                value_stack.push_back(ValType::NumType(NumType::I32));
+            }
             // i32.const: [] -> [i32]
             0x41 => {
                 let _num = wasm.read_var_i32()?;
diff --git a/tests/arithmetic/division.rs b/tests/arithmetic/division.rs
index 1a2e899a..d5ece68a 100644
--- a/tests/arithmetic/division.rs
+++ b/tests/arithmetic/division.rs
@@ -80,3 +80,65 @@ pub fn division_signed_panic_result_unrepresentable() {
         wasm::Error::RuntimeError(wasm::RuntimeError::UnrepresentableResult)
     );
 }
+
+
+/// A simple function to test unsigned division
+#[test_log::test]
+pub fn division_unsigned_simple() {
+    use wasm::{validate, RuntimeInstance};
+
+    let wat = r#"
+    (module
+        (func (export "unsigned_division") (param $divisor i32) (param $dividend i32) (result i32)
+            local.get $divisor
+            local.get $dividend
+            i32.div_u)
+    )
+    "#;
+
+    let wasm_bytes = wat::parse_str(wat).unwrap();
+
+    let validation_info = validate(&wasm_bytes).expect("validation failed");
+
+    let mut instance = RuntimeInstance::new(&validation_info).expect("instantiation failed");
+
+    assert_eq!(10, instance.invoke_func(0, (20, 2)).unwrap());
+    assert_eq!(9_001, instance.invoke_func(0, (81_018_001, 9_001)).unwrap());
+    assert_eq!(0, instance.invoke_func(0, (i32::MIN, -1)).unwrap());
+
+
+    assert_eq!(0, instance.invoke_func(0, (i32::MIN, -1)).unwrap());
+    assert_eq!(-20, instance.invoke_func(0, (-20, 1)).unwrap());
+    assert_eq!(2147483638, instance.invoke_func(0, (-20, 2)).unwrap());
+    assert_eq!(1431655758, instance.invoke_func(0, (-20, 3)).unwrap());
+    assert_eq!(1073741819, instance.invoke_func(0, (-20, 4)).unwrap());
+
+}
+
+/// A simple function to test unsigned division's RuntimeError when dividing by 0
+#[test_log::test]
+pub fn division_unsigned_panic_dividend_0() {
+    use wasm::{validate, RuntimeInstance};
+
+    let wat = r#"
+    (module
+        (func (export "unsigned_division") (param $divisor i32) (param $dividend i32) (result i32)
+            local.get $divisor
+            local.get $dividend
+            i32.div_u)
+    )
+    "#;
+
+    let wasm_bytes = wat::parse_str(wat).unwrap();
+
+    let validation_info = validate(&wasm_bytes).expect("validation failed");
+
+    let mut instance = RuntimeInstance::new(&validation_info).expect("instantiation failed");
+
+    let result = instance.invoke_func::<(i32, i32), i32>(0, (222, 0));
+
+    assert_eq!(
+        result.unwrap_err(),
+        wasm::Error::RuntimeError(wasm::RuntimeError::DivideBy0)
+    );
+}