diff --git a/src/isa.rs b/src/isa.rs
index e4d737a..3821e1b 100644
--- a/src/isa.rs
+++ b/src/isa.rs
@@ -42,8 +42,8 @@ impl Icode {
     pub const RETURN: u8 = 0x1 << 6;
     pub const KEEP: u8 = 0x1 << 7;
 
-    // Hacking around the weird official names for some things
-    pub const XOR: u8 = Icode::ORA;
+    // Hacking around the official names for some things
+    pub const XOR: u8 = Icode::EOR;
     pub const EQ: u8 = Icode::EQL;
     pub const NE: u8 = Icode::NEQ;
     pub const GT: u8 = Icode::GTH;
diff --git a/src/vm.rs b/src/vm.rs
index 716191e..2b6707e 100644
--- a/src/vm.rs
+++ b/src/vm.rs
@@ -418,7 +418,7 @@ impl Uxn {
                         push(wst.clone(), a | b)?;
                     }
                     (_, _, _, Icode::EOR) => {
-                        // XOR a8 b8 -- c8
+                        // XOR a b -- c8
                         let b = pop(wst.clone())?;
                         let a = pop(wst.clone())?;
                         push(wst.clone(), a ^ b)?;
@@ -426,7 +426,7 @@ impl Uxn {
                     (_, _, _, Icode::SFT) => {
                         // SFT a shift8 -- b
                         let shift = wst.borrow_mut().pop1()?;
-                        let [left, right] = [shift >> 4, shift & 0xF];
+                        let [left, right] = [shift >> 4 & 0xF, shift & 0xF];
                         let a = pop(wst.clone())?;
                         push(wst.clone(), (a >> right) << left)?;
                     }
diff --git a/tests/vm_tests.rs b/tests/vm_tests.rs
index 251ec99..c73c337 100644
--- a/tests/vm_tests.rs
+++ b/tests/vm_tests.rs
@@ -713,3 +713,282 @@ fn test_sta2() {
     assert_eq!(vm.wst.borrow().idx(), 0);
     assert_eq!(vm.lda2(0x010c), Ok(0xFFEE));
 }
+
+#[test]
+fn test_add() {
+    nofmt::pls! {
+        let mut vm = Uxn::of1(&[
+            Icode::LIT | Icode::SHORT, 0xFF, 0x01, Icode::ADD, Icode::BRK
+        ]);
+    }
+    assert_eq!(vm.run(64), Err(UxnError::Break));
+    assert_eq!(vm.wst.borrow().idx(), 1);
+    assert_eq!(vm.wst.borrow().peek1(), Ok(0x00));
+}
+
+#[test]
+fn test_add2() {
+    // The incantation for adding a u8 to a u16 is probably something involving using [ LIT #00 SWP ] but yeesh.
+    nofmt::pls! {
+        let mut vm = Uxn::of1(&[
+            Icode::LIT | Icode::SHORT, 0xFF, 0x00,
+            Icode::LIT, 0x01,
+
+            // Promote u8 to u16 by stuffing an #00 in there. Yes coulda used a bigger lit but playing with the upcast.
+            Icode::LIT, 0x0,
+            Icode::SWP,
+
+            // u16 + u16
+            Icode::ADD | Icode::SHORT,
+            Icode::BRK
+        ]);
+    }
+    assert_eq!(vm.run(64), Err(UxnError::Break));
+    assert_eq!(vm.wst.borrow().idx(), 2);
+    assert_eq!(vm.wst.borrow().peek2(), Ok(0xFF01));
+}
+
+#[test]
+fn test_sub() {
+    nofmt::pls! {
+        let mut vm = Uxn::of1(&[
+            Icode::LIT | Icode::SHORT, 0xFF, 0x01, Icode::SUB, Icode::BRK
+        ]);
+    }
+    assert_eq!(vm.run(64), Err(UxnError::Break));
+    assert_eq!(vm.wst.borrow().idx(), 1);
+    assert_eq!(vm.wst.borrow().peek1(), Ok(0xFE));
+}
+
+#[test]
+fn test_sub2() {
+    // The incantation for adding a u8 to a u16 is probably something involving using [ LIT #00 SWP ] but yeesh.
+    nofmt::pls! {
+        let mut vm = Uxn::of1(&[
+            Icode::LIT | Icode::SHORT, 0xFF, 0xFF,
+            Icode::LIT, 0x01,
+
+            // Promote u8 to u16 by stuffing an #00 in there. Yes coulda used a bigger lit but playing with the upcast.
+            Icode::LIT, 0x0,
+            Icode::SWP,
+
+            Icode::SUB | Icode::SHORT,
+            Icode::BRK
+        ]);
+    }
+    assert_eq!(vm.run(64), Err(UxnError::Break));
+    assert_eq!(vm.wst.borrow().idx(), 2);
+    assert_eq!(vm.wst.borrow().peek2(), Ok(0xFFFE));
+}
+
+#[test]
+fn test_mul() {
+    nofmt::pls! {
+        let mut vm = Uxn::of1(&[
+            Icode::LIT | Icode::SHORT, 0x4, 0x4, Icode::MUL, Icode::BRK
+        ]);
+    }
+    assert_eq!(vm.run(64), Err(UxnError::Break));
+    assert_eq!(vm.wst.borrow().idx(), 1);
+    assert_eq!(vm.wst.borrow().peek1(), Ok(0x10));
+}
+
+#[test]
+fn test_mul2() {
+    // The incantation for adding a u8 to a u16 is probably something involving using [ LIT #00 SWP ] but yeesh.
+    nofmt::pls! {
+        let mut vm = Uxn::of1(&[
+            Icode::LIT | Icode::SHORT, 0xFF, 0xFF,
+            Icode::LIT, 0x01,
+
+            // Promote u8 to u16 by stuffing an #00 in there. Yes coulda used a bigger lit but playing with the upcast.
+            Icode::LIT, 0x0,
+            Icode::SWP,
+
+            Icode::MUL | Icode::SHORT,
+            Icode::BRK
+        ]);
+    }
+    assert_eq!(vm.run(64), Err(UxnError::Break));
+    assert_eq!(vm.wst.borrow().idx(), 2);
+    assert_eq!(vm.wst.borrow().peek2(), Ok(0xFFFF));
+}
+
+#[test]
+fn test_div() {
+    nofmt::pls! {
+        let mut vm = Uxn::of1(&[
+            Icode::LIT | Icode::SHORT, 0x10, 0x4, Icode::DIV, Icode::BRK
+        ]);
+    }
+    assert_eq!(vm.run(64), Err(UxnError::Break));
+    assert_eq!(vm.wst.borrow().idx(), 1);
+    assert_eq!(vm.wst.borrow().peek1(), Ok(0x4));
+}
+
+#[test]
+fn test_div2() {
+    // The incantation for adding a u8 to a u16 is probably something involving using [ LIT #00 SWP ] but yeesh.
+    nofmt::pls! {
+        let mut vm = Uxn::of1(&[
+            Icode::LIT | Icode::SHORT, 0x10, 0x00,
+            Icode::LIT, 0x2,
+
+            // Promote u8 to u16 by stuffing an #00 in there. Yes coulda used a bigger lit but playing with the upcast.
+            Icode::LIT, 0x0,
+            Icode::SWP,
+
+            Icode::DIV | Icode::SHORT,
+            Icode::BRK
+        ]);
+    }
+    assert_eq!(vm.run(64), Err(UxnError::Break));
+    assert_eq!(vm.wst.borrow().idx(), 2);
+    assert_eq!(vm.wst.borrow().peek2(), Ok(0x0800));
+}
+
+#[test]
+fn test_and() {
+    nofmt::pls! {
+        let mut vm = Uxn::of1(&[
+            Icode::LIT | Icode::SHORT, 0xF, 0x1, Icode::AND, Icode::BRK
+        ]);
+    }
+    assert_eq!(vm.run(64), Err(UxnError::Break));
+    assert_eq!(vm.wst.borrow().idx(), 1);
+    assert_eq!(vm.wst.borrow().peek1(), Ok(0x1));
+}
+
+#[test]
+fn test_and2() {
+    // The incantation for adding a u8 to a u16 is probably something involving using [ LIT #00 SWP ] but yeesh.
+    nofmt::pls! {
+        let mut vm = Uxn::of1(&[
+            Icode::LIT | Icode::SHORT, 0x10, 0x03,
+            Icode::LIT, 0x2,
+
+            // Promote u8 to u16 by stuffing an #00 in there. Yes coulda used a bigger lit but playing with the upcast.
+            Icode::LIT, 0x0,
+            Icode::SWP,
+
+            Icode::AND | Icode::SHORT,
+            Icode::BRK
+        ]);
+    }
+    assert_eq!(vm.run(64), Err(UxnError::Break));
+    assert_eq!(vm.wst.borrow().idx(), 2);
+    assert_eq!(vm.wst.borrow().peek2(), Ok(0x0002));
+}
+
+#[test]
+fn test_or() {
+    nofmt::pls! {
+        let mut vm = Uxn::of1(&[
+            Icode::LIT | Icode::SHORT, 0xF, 0x1,
+            Icode::OR,
+            Icode::BRK
+        ]);
+    }
+    assert_eq!(vm.run(64), Err(UxnError::Break));
+    assert_eq!(vm.wst.borrow().idx(), 1);
+    assert_eq!(vm.wst.borrow().peek1(), Ok(0xF));
+}
+
+#[test]
+fn test_or2() {
+    // The incantation for adding a u8 to a u16 is probably something involving using [ LIT #00 SWP ] but yeesh.
+    nofmt::pls! {
+        let mut vm = Uxn::of1(&[
+            Icode::LIT | Icode::SHORT, 0x10, 0x03,
+            Icode::LIT, 0x2,
+
+            // Promote u8 to u16 by stuffing an #00 in there. Yes coulda used a bigger lit but playing with the upcast.
+            Icode::LIT, 0x0,
+            Icode::SWP,
+
+            Icode::OR | Icode::SHORT,
+            Icode::BRK
+        ]);
+    }
+    assert_eq!(vm.run(64), Err(UxnError::Break));
+    assert_eq!(vm.wst.borrow().idx(), 2);
+    assert_eq!(vm.wst.borrow().peek2(), Ok(0x1003));
+}
+
+#[test]
+fn test_xor() {
+    nofmt::pls! {
+        let mut vm = Uxn::of1(&[
+            Icode::LIT | Icode::SHORT, 0xF, 0x1,
+            Icode::XOR,
+            Icode::BRK
+        ]);
+    }
+    assert_eq!(vm.run(64), Err(UxnError::Break));
+    assert_eq!(vm.wst.borrow().idx(), 1);
+    assert_eq!(vm.wst.borrow().peek1(), Ok(0xE));
+}
+
+#[test]
+fn test_xor2() {
+    // The incantation for adding a u8 to a u16 is probably something involving using [ LIT #00 SWP ] but yeesh.
+    nofmt::pls! {
+        let mut vm = Uxn::of1(&[
+            Icode::LIT | Icode::SHORT, 0x10, 0x03,
+            Icode::LIT, 0x2,
+
+            // Promote u8 to u16 by stuffing an #00 in there. Yes coulda used a bigger lit but playing with the upcast.
+            Icode::LIT, 0x0,
+            Icode::SWP,
+
+            Icode::XOR | Icode::SHORT,
+            Icode::BRK
+        ]);
+    }
+    assert_eq!(vm.run(64), Err(UxnError::Break));
+    assert_eq!(vm.wst.borrow().idx(), 2);
+    assert_eq!(vm.wst.borrow().peek2(), Ok(0x1001));
+}
+
+#[test]
+fn test_sft_l() {
+    nofmt::pls! {
+        let mut vm = Uxn::of1(&[
+            Icode::LIT | Icode::SHORT, 0x0F, 0x10,
+            Icode::SFT,
+            Icode::BRK
+        ]);
+    }
+    assert_eq!(vm.run(64), Err(UxnError::Break));
+    assert_eq!(vm.wst.borrow().idx(), 1);
+    assert_eq!(vm.wst.borrow().peek1(), Ok(0x1E));
+}
+
+#[test]
+fn test_sft_r() {
+    nofmt::pls! {
+        let mut vm = Uxn::of1(&[
+            Icode::LIT | Icode::SHORT, 0x0F, 0x01,
+            Icode::SFT,
+            Icode::BRK
+        ]);
+    }
+    assert_eq!(vm.run(64), Err(UxnError::Break));
+    assert_eq!(vm.wst.borrow().idx(), 1);
+    assert_eq!(vm.wst.borrow().peek1(), Ok(0x07));
+}
+
+#[test]
+fn test_sft_rl2() {
+    nofmt::pls! {
+        let mut vm = Uxn::of1(&[
+            Icode::LIT | Icode::SHORT, 0x80, 0x01,
+            Icode::LIT, 0x21, // Shift truncates, so this will unset all the bits
+            Icode::SFT | Icode::SHORT,
+            Icode::BRK
+        ]);
+    }
+    assert_eq!(vm.run(64), Err(UxnError::Break));
+    assert_eq!(vm.wst.borrow().idx(), 2);
+    assert_eq!(vm.wst.borrow().peek2(), Ok(0x0000));
+}