LSR instruction

snes-core/src/utils/alu.rs

@@ -109,6 +109,15 @@ pub fn asl<T: SnesNum>(target: T) -> (T, [Flags; 3]) {
     ])
 }
 
+pub fn lsr<T: SnesNum>(target: T) -> (T, [Flags; 3]) {
+    let result = target.lsr();
+    (result, [
+        Negative(false),
+        Zero(result.is_zero()),
+        Carry(result.to_u32() & 1 == 1), // High bit becomes carry
+    ])
+}
+
 pub fn eor<T: SnesNum>(target: T, value: T) -> (T, [Flags; 2]) {
     let result = target.xor(value);
     (result, [

snes-core/src/utils/num_trait.rs

@@ -6,6 +6,7 @@ pub trait SnesNum: Copy + Clone + Sized + Eq + PartialEq {
     fn sbc_snes(&self, v: Self, carry: bool) -> Self;
     fn and(&self, v: Self) -> Self;
     fn asl(&self) -> Self;
+    fn lsr(&self) -> Self;
     fn xor(&self, v: Self) -> Self;
     fn is_negative(&self) -> bool;
     fn is_zero(&self) -> bool;
@@ -68,6 +69,10 @@ macro_rules! define_impl {
                 (* self) << 1
             }
 
+            fn lsr(&self) -> $t {
+                (* self) >> 1
+            }
+
             fn xor(&self, v: $t) -> $t {
                 (* self) ^ v
             }