diff --git a/.gitignore b/.gitignore
index 499fa03..c73e0df 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,7 +1,4 @@
 /target
-/hbbytecode/src/opcode.rs
-/hbbytecode/src/ops.rs
-/hblang/src/instrs.rs
-/hblang/src/disasm.rs
+/hbbytecode/src/instrs.rs
 /.rgignore
-rust-ice-*
+rustc-ice-*
diff --git a/Cargo.lock b/Cargo.lock
index a7d03f3..49297bc 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -20,6 +20,7 @@ version = "0.1.0"
 name = "hblang"
 version = "0.1.0"
 dependencies = [
+ "hbbytecode",
  "hbvm",
  "regalloc2",
 ]
diff --git a/hbbytecode/Cargo.toml b/hbbytecode/Cargo.toml
index 1b50f51..a542869 100644
--- a/hbbytecode/Cargo.toml
+++ b/hbbytecode/Cargo.toml
@@ -2,3 +2,8 @@
 name = "hbbytecode"
 version = "0.1.0"
 edition = "2018"
+
+[features]
+default = ["disasm"]
+std = []
+disasm = ["std"]
diff --git a/hbbytecode/build.rs b/hbbytecode/build.rs
index 9ac45d2..6b549c6 100644
--- a/hbbytecode/build.rs
+++ b/hbbytecode/build.rs
@@ -1,58 +1,208 @@
 #![feature(iter_next_chunk)]
 
+use std::{collections::HashSet, fmt::Write};
+
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     println!("cargo:rerun-if-changed=build.rs");
     println!("cargo:rerun-if-changed=instructions.in");
 
     let mut generated = String::new();
-    gen_op_structs(&mut generated)?;
-    std::fs::write("src/ops.rs", generated)?;
-
-    let mut generated = String::new();
-    gen_op_codes(&mut generated)?;
-    std::fs::write("src/opcode.rs", generated)?;
+    gen_instrs(&mut generated)?;
+    std::fs::write("src/instrs.rs", generated)?;
 
     Ok(())
 }
 
-fn gen_op_structs(generated: &mut String) -> std::fmt::Result {
-    use std::fmt::Write;
-    let mut seen = std::collections::HashSet::new();
+fn gen_instrs(generated: &mut String) -> Result<(), Box<dyn std::error::Error>> {
+    writeln!(generated, "#![allow(dead_code)] #![allow(clippy::upper_case_acronyms)]")?;
     writeln!(generated, "use crate::*;")?;
-    for [.., args, _] in instructions() {
-        if !seen.insert(args) {
-            continue;
-        }
 
-        writeln!(generated, "#[derive(Clone, Copy, Debug)]")?;
-        writeln!(generated, "#[repr(packed)]")?;
-        write!(generated, "pub struct Ops{args}(")?;
-        let mut first = true;
-        for ch in args.chars().filter(|&ch| ch != 'N') {
-            if !std::mem::take(&mut first) {
-                write!(generated, ",")?;
+    '_opcode_structs: {
+        let mut seen = HashSet::new();
+        for [.., args, _] in instructions() {
+            if !seen.insert(args) {
+                continue;
             }
-            write!(generated, "pub Op{ch}")?;
+
+            writeln!(generated, "#[derive(Clone, Copy, Debug)]")?;
+            writeln!(generated, "#[repr(packed)]")?;
+            write!(generated, "pub struct Ops{args}(")?;
+            let mut first = true;
+            for ch in args.chars().filter(|&ch| ch != 'N') {
+                if !std::mem::take(&mut first) {
+                    write!(generated, ",")?;
+                }
+                write!(generated, "pub Op{ch}")?;
+            }
+            writeln!(generated, ");")?;
+            writeln!(generated, "unsafe impl BytecodeItem for Ops{args} {{}}")?;
         }
-        writeln!(generated, ");")?;
-        writeln!(generated, "unsafe impl BytecodeItem for Ops{args} {{}}")?;
     }
 
+    '_max_size: {
+        let max = instructions()
+            .map(
+                |[_, _, ty, _]| {
+                    if ty == "N" {
+                        1
+                    } else {
+                        iter_args(ty).map(arg_to_width).sum::<usize>() + 1
+                    }
+                },
+            )
+            .max()
+            .unwrap();
+
+        writeln!(generated, "pub const MAX_SIZE: usize = {max};")?;
+    }
+
+    '_encoders: {
+        for [op, name, ty, doc] in instructions() {
+            writeln!(generated, "/// {}", doc.trim_matches('"'))?;
+            let name = name.to_lowercase();
+            let args = comma_sep(
+                iter_args(ty)
+                    .enumerate()
+                    .map(|(i, c)| format!("{}{i}: {}", arg_to_name(c), arg_to_type(c))),
+            );
+            writeln!(generated, "pub fn {name}({args}) -> (usize, [u8; MAX_SIZE]) {{")?;
+            let arg_names =
+                comma_sep(iter_args(ty).enumerate().map(|(i, c)| format!("{}{i}", arg_to_name(c))));
+            writeln!(generated, "    unsafe {{ crate::encode({ty}({op}, {arg_names})) }}")?;
+            writeln!(generated, "}}")?;
+        }
+    }
+
+    '_structs: {
+        let mut seen = std::collections::HashSet::new();
+        for [_, _, ty, _] in instructions() {
+            if !seen.insert(ty) {
+                continue;
+            }
+            let types = comma_sep(iter_args(ty).map(arg_to_type).map(|s| s.to_string()));
+            writeln!(generated, "#[repr(packed)] pub struct {ty}(u8, {types});")?;
+        }
+    }
+
+    '_name_list: {
+        writeln!(generated, "pub const NAMES: [&str; {}] = [", instructions().count())?;
+        for [_, name, _, _] in instructions() {
+            writeln!(generated, "    \"{}\",", name.to_lowercase())?;
+        }
+        writeln!(generated, "];")?;
+    }
+
+    let instr = "Instr";
+    let oper = "Oper";
+
+    '_instr_enum: {
+        writeln!(generated, "#[derive(Debug, Clone, Copy, PartialEq, Eq)] #[repr(u8)]")?;
+        writeln!(generated, "pub enum {instr} {{")?;
+        for [id, name, ..] in instructions() {
+            writeln!(generated, "    {name} = {id},")?;
+        }
+        writeln!(generated, "}}")?;
+    }
+
+    '_arg_kind: {
+        writeln!(generated, "#[derive(Debug, Clone, Copy, PartialEq, Eq)]")?;
+        writeln!(generated, "pub enum {oper} {{")?;
+        let mut seen = HashSet::new();
+        for ty in instructions().flat_map(|[.., ty, _]| iter_args(ty)) {
+            if !seen.insert(ty) {
+                continue;
+            }
+            writeln!(generated, "    {ty}({}),", arg_to_type(ty))?;
+        }
+        writeln!(generated, "}}")?;
+    }
+
+    '_parse_opers: {
+        writeln!(
+            generated,
+            "/// This assumes the instruction byte is still at the beginning of the buffer"
+        )?;
+        writeln!(generated, "#[cfg(feature = \"disasm\")]")?;
+        writeln!(generated, "pub fn parse_args(bytes: &mut &[u8], kind: {instr}, buf: &mut std::vec::Vec<{oper}>) -> Option<()> {{")?;
+        writeln!(generated, "    match kind {{")?;
+        let mut instrs = instructions().collect::<Vec<_>>();
+        instrs.sort_unstable_by_key(|&[.., ty, _]| ty);
+        for group in instrs.chunk_by(|[.., a, _], [.., b, _]| a == b) {
+            let ty = group[0][2];
+            for &[_, name, ..] in group {
+                writeln!(generated, "        | {instr}::{name}")?;
+            }
+            generated.pop();
+            writeln!(generated, " => {{")?;
+            if iter_args(ty).count() != 0 {
+                writeln!(generated, "            let data = crate::decode::<{ty}>(bytes)?;")?;
+                writeln!(
+                    generated,
+                    "            buf.extend([{}]);",
+                    comma_sep(
+                        iter_args(ty).zip(1u32..).map(|(t, i)| format!("{oper}::{t}(data.{i})"))
+                    )
+                )?;
+            } else {
+                writeln!(generated, "            crate::decode::<{ty}>(bytes)?;")?;
+            }
+
+            writeln!(generated, "        }}")?;
+        }
+        writeln!(generated, "    }}")?;
+        writeln!(generated, "    Some(())")?;
+        writeln!(generated, "}}")?;
+    }
+
+    std::fs::write("src/instrs.rs", generated)?;
     Ok(())
 }
 
-fn gen_op_codes(generated: &mut String) -> std::fmt::Result {
-    use std::fmt::Write;
-    for [op, name, _, comment] in instructions() {
-        writeln!(generated, "#[doc = {comment}]")?;
-        writeln!(generated, "pub const {name}: u8 = {op};")?;
-    }
-    Ok(())
+fn comma_sep(items: impl Iterator<Item = String>) -> String {
+    items.map(|item| item.to_string()).collect::<Vec<_>>().join(", ")
 }
 
 fn instructions() -> impl Iterator<Item = [&'static str; 4]> {
     include_str!("../hbbytecode/instructions.in")
         .lines()
-        .map(|line| line.strip_suffix(';').unwrap())
+        .filter_map(|line| line.strip_suffix(';'))
         .map(|line| line.splitn(4, ',').map(str::trim).next_chunk().unwrap())
 }
+
+fn arg_to_type(arg: char) -> &'static str {
+    match arg {
+        'R' | 'B' => "u8",
+        'H' => "u16",
+        'W' => "u32",
+        'D' | 'A' => "u64",
+        'P' => "i16",
+        'O' => "i32",
+        _ => panic!("unknown type: {}", arg),
+    }
+}
+
+fn arg_to_width(arg: char) -> usize {
+    match arg {
+        'R' | 'B' => 1,
+        'H' => 2,
+        'W' => 4,
+        'D' | 'A' => 8,
+        'P' => 2,
+        'O' => 4,
+        _ => panic!("unknown type: {}", arg),
+    }
+}
+
+fn arg_to_name(arg: char) -> &'static str {
+    match arg {
+        'R' => "reg",
+        'B' | 'H' | 'W' | 'D' => "imm",
+        'P' | 'O' => "offset",
+        'A' => "addr",
+        _ => panic!("unknown type: {}", arg),
+    }
+}
+
+fn iter_args(ty: &'static str) -> impl Iterator<Item = char> {
+    ty.chars().filter(|c| *c != 'N')
+}
diff --git a/hbbytecode/src/lib.rs b/hbbytecode/src/lib.rs
index bcebd5b..3a45841 100644
--- a/hbbytecode/src/lib.rs
+++ b/hbbytecode/src/lib.rs
@@ -1,10 +1,12 @@
 #![no_std]
 
-pub use crate::ops::*;
+#[cfg(feature = "std")]
+extern crate std;
+
+pub use crate::instrs::*;
 use core::convert::TryFrom;
 
-pub mod opcode;
-mod ops;
+mod instrs;
 
 type OpR = u8;
 
@@ -22,6 +24,38 @@ type OpD = u64;
 pub unsafe trait BytecodeItem {}
 unsafe impl BytecodeItem for u8 {}
 
+impl TryFrom<u8> for Instr {
+    type Error = u8;
+
+    #[inline]
+    fn try_from(value: u8) -> Result<Self, Self::Error> {
+        #[cold]
+        fn failed(value: u8) -> Result<Instr, u8> {
+            Err(value)
+        }
+
+        if value < NAMES.len() as u8 {
+            unsafe { Ok(std::mem::transmute::<u8, Instr>(value)) }
+        } else {
+            failed(value)
+        }
+    }
+}
+
+#[inline]
+unsafe fn encode<T>(instr: T) -> (usize, [u8; instrs::MAX_SIZE]) {
+    let mut buf = [0; instrs::MAX_SIZE];
+    core::ptr::write(buf.as_mut_ptr() as *mut T, instr);
+    (core::mem::size_of::<T>(), buf)
+}
+
+#[inline]
+fn decode<T>(binary: &mut &[u8]) -> Option<T> {
+    let (front, rest) = std::mem::take(binary).split_at_checked(core::mem::size_of::<T>())?;
+    *binary = rest;
+    unsafe { Some(core::ptr::read(front.as_ptr() as *const T)) }
+}
+
 /// Rounding mode
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 #[repr(u8)]
@@ -39,3 +73,181 @@ impl TryFrom<u8> for RoundingMode {
         (value <= 3).then(|| unsafe { core::mem::transmute(value) }).ok_or(())
     }
 }
+
+#[cfg(feature = "disasm")]
+#[derive(Clone, Copy)]
+pub enum DisasmItem {
+    Func,
+    Global,
+}
+
+#[cfg(feature = "disasm")]
+pub fn disasm(
+    binary: &mut &[u8],
+    functions: &std::collections::BTreeMap<u32, (&str, u32, DisasmItem)>,
+    out: &mut impl std::io::Write,
+    mut eca_handler: impl FnMut(&mut &[u8]),
+) -> std::io::Result<()> {
+    use {
+        self::instrs::Instr,
+        std::{
+            collections::{hash_map::Entry, HashMap},
+            convert::TryInto,
+            vec::Vec,
+        },
+    };
+
+    fn instr_from_byte(b: u8) -> std::io::Result<Instr> {
+        if b as usize >= instrs::NAMES.len() {
+            return Err(std::io::ErrorKind::InvalidData.into());
+        }
+        Ok(unsafe { std::mem::transmute::<u8, Instr>(b) })
+    }
+
+    let mut labels = HashMap::<u32, u32>::default();
+    let mut buf = Vec::<instrs::Oper>::new();
+    let mut has_cycle = false;
+    let mut has_oob = false;
+
+    '_offset_pass: for (&off, &(_name, len, kind)) in functions.iter() {
+        if matches!(kind, DisasmItem::Global) {
+            continue;
+        }
+
+        let prev = *binary;
+
+        *binary = &binary[..off as usize];
+
+        let mut label_count = 0;
+        while let Some(&byte) = binary.first() {
+            let offset: i32 = (prev.len() - binary.len()).try_into().unwrap();
+            if offset as u32 == off + len {
+                break;
+            }
+            let Ok(inst) = instr_from_byte(byte) else { break };
+            instrs::parse_args(binary, inst, &mut buf).ok_or(std::io::ErrorKind::OutOfMemory)?;
+
+            for op in buf.drain(..) {
+                let rel = match op {
+                    instrs::Oper::O(rel) => rel,
+                    instrs::Oper::P(rel) => rel.into(),
+                    _ => continue,
+                };
+
+                has_cycle |= rel == 0;
+
+                let global_offset: u32 = (offset + rel).try_into().unwrap();
+                if functions.get(&global_offset).is_some() {
+                    continue;
+                }
+                label_count += match labels.entry(global_offset) {
+                    Entry::Occupied(_) => 0,
+                    Entry::Vacant(entry) => {
+                        entry.insert(label_count);
+                        1
+                    }
+                }
+            }
+
+            if matches!(inst, Instr::ECA) {
+                eca_handler(binary);
+            }
+        }
+
+        *binary = prev;
+    }
+
+    let mut ordered = functions.iter().collect::<Vec<_>>();
+    ordered.sort_unstable_by_key(|(_, (name, _, _))| name);
+
+    '_dump: for (&off, &(name, len, kind)) in ordered {
+        if matches!(kind, DisasmItem::Global) {
+            continue;
+        }
+        let prev = *binary;
+
+        writeln!(out, "{name}:")?;
+
+        *binary = &binary[..off as usize];
+        while let Some(&byte) = binary.first() {
+            let offset: i32 = (prev.len() - binary.len()).try_into().unwrap();
+            if offset as u32 == off + len {
+                break;
+            }
+            let Ok(inst) = instr_from_byte(byte) else {
+                writeln!(out, "invalid instr {byte}")?;
+                break;
+            };
+            instrs::parse_args(binary, inst, &mut buf).unwrap();
+
+            if let Some(label) = labels.get(&offset.try_into().unwrap()) {
+                write!(out, "{:>2}: ", label)?;
+            } else {
+                write!(out, "    ")?;
+            }
+
+            write!(out, "{inst:<8?} ")?;
+
+            'a: for (i, op) in buf.drain(..).enumerate() {
+                if i != 0 {
+                    write!(out, ", ")?;
+                }
+
+                let rel = 'b: {
+                    match op {
+                        instrs::Oper::O(rel) => break 'b rel,
+                        instrs::Oper::P(rel) => break 'b rel.into(),
+                        instrs::Oper::R(r) => write!(out, "r{r}")?,
+                        instrs::Oper::B(b) => write!(out, "{b}b")?,
+                        instrs::Oper::H(h) => write!(out, "{h}h")?,
+                        instrs::Oper::W(w) => write!(out, "{w}w")?,
+                        instrs::Oper::D(d) if (d as i64) < 0 => write!(out, "{}d", d as i64)?,
+                        instrs::Oper::D(d) => write!(out, "{d}d")?,
+                        instrs::Oper::A(a) => write!(out, "{a}a")?,
+                    }
+
+                    continue 'a;
+                };
+
+                let global_offset: u32 = (offset + rel).try_into().unwrap();
+                if let Some(&(name, ..)) = functions.get(&global_offset) {
+                    if name.contains('\0') {
+                        write!(out, ":{name:?}")?;
+                    } else {
+                        write!(out, ":{name}")?;
+                    }
+                } else {
+                    let local_has_oob = global_offset < off
+                        || global_offset > off + len
+                        || instr_from_byte(prev[global_offset as usize]).is_err()
+                        || prev[global_offset as usize] == 0;
+                    has_oob |= local_has_oob;
+                    let label = labels.get(&global_offset).unwrap();
+                    if local_has_oob {
+                        write!(out, "!!!!!!!!!{rel}")?;
+                    } else {
+                        write!(out, ":{label}")?;
+                    }
+                }
+            }
+
+            writeln!(out)?;
+
+            if matches!(inst, Instr::ECA) {
+                eca_handler(binary);
+            }
+        }
+
+        *binary = prev;
+    }
+
+    if has_oob {
+        return Err(std::io::ErrorKind::InvalidInput.into());
+    }
+
+    if has_cycle {
+        return Err(std::io::ErrorKind::TimedOut.into());
+    }
+
+    Ok(())
+}
diff --git a/hblang/Cargo.toml b/hblang/Cargo.toml
index 90a0c45..a2f7887 100644
--- a/hblang/Cargo.toml
+++ b/hblang/Cargo.toml
@@ -8,5 +8,6 @@ name = "hbc"
 path = "src/main.rs"
 
 [dependencies]
+hbbytecode = { version = "0.1.0", path = "../hbbytecode" }
 hbvm = { path = "../hbvm", features = ["nightly"] }
 regalloc2 = { git = "https://github.com/jakubDoka/regalloc2" }
diff --git a/hblang/build.rs b/hblang/build.rs
deleted file mode 100644
index 1598082..0000000
--- a/hblang/build.rs
+++ /dev/null
@@ -1,183 +0,0 @@
-#![feature(iter_next_chunk)]
-use std::{collections::HashSet, fmt::Write};
-
-fn main() -> Result<(), Box<dyn std::error::Error>> {
-    println!("cargo:rerun-if-changed=build.rs");
-    println!("cargo:rerun-if-changed=../hbbytecode/instructions.in");
-
-    gen_instrs()?;
-
-    Ok(())
-}
-
-fn gen_instrs() -> Result<(), Box<dyn std::error::Error>> {
-    let mut generated = String::new();
-
-    writeln!(generated, "#![allow(dead_code)] #![allow(clippy::upper_case_acronyms)]")?;
-
-    '_max_size: {
-        let max = instructions()
-            .map(
-                |[_, _, ty, _]| {
-                    if ty == "N" {
-                        1
-                    } else {
-                        iter_args(ty).map(arg_to_width).sum::<usize>() + 1
-                    }
-                },
-            )
-            .max()
-            .unwrap();
-
-        writeln!(generated, "pub const MAX_SIZE: usize = {max};")?;
-    }
-
-    '_encoders: {
-        for [op, name, ty, doc] in instructions() {
-            writeln!(generated, "/// {}", doc.trim_matches('"'))?;
-            let name = name.to_lowercase();
-            let args = comma_sep(
-                iter_args(ty)
-                    .enumerate()
-                    .map(|(i, c)| format!("{}{i}: {}", arg_to_name(c), arg_to_type(c))),
-            );
-            writeln!(generated, "pub fn {name}({args}) -> (usize, [u8; MAX_SIZE]) {{")?;
-            let arg_names =
-                comma_sep(iter_args(ty).enumerate().map(|(i, c)| format!("{}{i}", arg_to_name(c))));
-            writeln!(generated, "    unsafe {{ crate::encode({ty}({op}, {arg_names})) }}")?;
-            writeln!(generated, "}}")?;
-        }
-    }
-
-    '_structs: {
-        let mut seen = std::collections::HashSet::new();
-        for [_, _, ty, _] in instructions() {
-            if !seen.insert(ty) {
-                continue;
-            }
-            let types = comma_sep(iter_args(ty).map(arg_to_type).map(|s| s.to_string()));
-            writeln!(generated, "#[repr(packed)] pub struct {ty}(u8, {types});")?;
-        }
-    }
-
-    '_name_list: {
-        writeln!(generated, "pub const NAMES: [&str; {}] = [", instructions().count())?;
-        for [_, name, _, _] in instructions() {
-            writeln!(generated, "    \"{}\",", name.to_lowercase())?;
-        }
-        writeln!(generated, "];")?;
-    }
-
-    let instr = "Instr";
-    let oper = "Oper";
-
-    '_instr_enum: {
-        writeln!(generated, "#[derive(Debug, Clone, Copy, PartialEq, Eq)] #[repr(u8)]")?;
-        writeln!(generated, "pub enum {instr} {{")?;
-        for [id, name, ..] in instructions() {
-            writeln!(generated, "    {name} = {id},")?;
-        }
-        writeln!(generated, "}}")?;
-    }
-
-    '_arg_kind: {
-        writeln!(generated, "#[derive(Debug, Clone, Copy, PartialEq, Eq)]")?;
-        writeln!(generated, "pub enum {oper} {{")?;
-        let mut seen = HashSet::new();
-        for ty in instructions().flat_map(|[.., ty, _]| iter_args(ty)) {
-            if !seen.insert(ty) {
-                continue;
-            }
-            writeln!(generated, "    {ty}({}),", arg_to_type(ty))?;
-        }
-        writeln!(generated, "}}")?;
-    }
-
-    '_parse_opers: {
-        writeln!(
-            generated,
-            "/// This assumes the instruction byte is still at the beginning of the buffer"
-        )?;
-        writeln!(generated, "pub fn parse_args(bytes: &mut &[u8], kind: {instr}, buf: &mut Vec<{oper}>) -> Option<()> {{")?;
-        writeln!(generated, "    match kind {{")?;
-        let mut instrs = instructions().collect::<Vec<_>>();
-        instrs.sort_unstable_by_key(|&[.., ty, _]| ty);
-        for group in instrs.chunk_by(|[.., a, _], [.., b, _]| a == b) {
-            let ty = group[0][2];
-            for &[_, name, ..] in group {
-                writeln!(generated, "        | {instr}::{name}")?;
-            }
-            generated.pop();
-            writeln!(generated, " => {{")?;
-            if iter_args(ty).count() != 0 {
-                writeln!(generated, "            let data = crate::decode::<{ty}>(bytes)?;")?;
-                writeln!(
-                    generated,
-                    "            buf.extend([{}]);",
-                    comma_sep(
-                        iter_args(ty).zip(1u32..).map(|(t, i)| format!("{oper}::{t}(data.{i})"))
-                    )
-                )?;
-            } else {
-                writeln!(generated, "            crate::decode::<{ty}>(bytes)?;")?;
-            }
-
-            writeln!(generated, "        }}")?;
-        }
-        writeln!(generated, "    }}")?;
-        writeln!(generated, "    Some(())")?;
-        writeln!(generated, "}}")?;
-    }
-
-    std::fs::write("src/instrs.rs", generated)?;
-    Ok(())
-}
-
-fn comma_sep(items: impl Iterator<Item = String>) -> String {
-    items.map(|item| item.to_string()).collect::<Vec<_>>().join(", ")
-}
-
-fn instructions() -> impl Iterator<Item = [&'static str; 4]> {
-    include_str!("../hbbytecode/instructions.in")
-        .lines()
-        .filter_map(|line| line.strip_suffix(';'))
-        .map(|line| line.splitn(4, ',').map(str::trim).next_chunk().unwrap())
-}
-
-fn arg_to_type(arg: char) -> &'static str {
-    match arg {
-        'R' | 'B' => "u8",
-        'H' => "u16",
-        'W' => "u32",
-        'D' | 'A' => "u64",
-        'P' => "i16",
-        'O' => "i32",
-        _ => panic!("unknown type: {}", arg),
-    }
-}
-
-fn arg_to_width(arg: char) -> usize {
-    match arg {
-        'R' | 'B' => 1,
-        'H' => 2,
-        'W' => 4,
-        'D' | 'A' => 8,
-        'P' => 2,
-        'O' => 4,
-        _ => panic!("unknown type: {}", arg),
-    }
-}
-
-fn arg_to_name(arg: char) -> &'static str {
-    match arg {
-        'R' => "reg",
-        'B' | 'H' | 'W' | 'D' => "imm",
-        'P' | 'O' => "offset",
-        'A' => "addr",
-        _ => panic!("unknown type: {}", arg),
-    }
-}
-
-fn iter_args(ty: &'static str) -> impl Iterator<Item = char> {
-    ty.chars().filter(|c| *c != 'N')
-}
diff --git a/hblang/src/lib.rs b/hblang/src/lib.rs
index 4bc6835..d305722 100644
--- a/hblang/src/lib.rs
+++ b/hblang/src/lib.rs
@@ -27,6 +27,7 @@ use {
         son::reg,
         ty::ArrayLen,
     },
+    hbbytecode as instrs,
     parser::Ast,
     std::{
         collections::{hash_map, BTreeMap, VecDeque},
@@ -52,7 +53,6 @@ pub mod codegen;
 pub mod parser;
 pub mod son;
 
-mod instrs;
 mod lexer;
 
 mod task {
@@ -715,7 +715,7 @@ impl Types {
         output: &mut impl std::io::Write,
         eca_handler: impl FnMut(&mut &[u8]),
     ) -> std::io::Result<()> {
-        use crate::DisasmItem;
+        use instrs::DisasmItem;
         let functions = self
             .funcs
             .iter()
@@ -744,7 +744,7 @@ impl Types {
                 (g.offset, (name, g.data.len() as Size, DisasmItem::Global))
             }))
             .collect::<BTreeMap<_, _>>();
-        crate::disasm(&mut sluce, &functions, output, eca_handler)
+        instrs::disasm(&mut sluce, &functions, output, eca_handler)
     }
 
     fn parama(&self, ret: impl Into<ty::Id>) -> ParamAlloc {
@@ -857,181 +857,6 @@ impl Types {
     }
 }
 
-#[inline]
-unsafe fn encode<T>(instr: T) -> (usize, [u8; instrs::MAX_SIZE]) {
-    let mut buf = [0; instrs::MAX_SIZE];
-    std::ptr::write(buf.as_mut_ptr() as *mut T, instr);
-    (std::mem::size_of::<T>(), buf)
-}
-
-#[inline]
-fn decode<T>(binary: &mut &[u8]) -> Option<T> {
-    unsafe { Some(std::ptr::read(binary.take(..std::mem::size_of::<T>())?.as_ptr() as *const T)) }
-}
-
-#[derive(Clone, Copy)]
-enum DisasmItem {
-    Func,
-    Global,
-}
-
-fn disasm(
-    binary: &mut &[u8],
-    functions: &BTreeMap<u32, (&str, u32, DisasmItem)>,
-    out: &mut impl std::io::Write,
-    mut eca_handler: impl FnMut(&mut &[u8]),
-) -> std::io::Result<()> {
-    use self::instrs::Instr;
-
-    fn instr_from_byte(b: u8) -> std::io::Result<Instr> {
-        if b as usize >= instrs::NAMES.len() {
-            return Err(std::io::ErrorKind::InvalidData.into());
-        }
-        Ok(unsafe { std::mem::transmute::<u8, Instr>(b) })
-    }
-
-    let mut labels = HashMap::<u32, u32>::default();
-    let mut buf = Vec::<instrs::Oper>::new();
-    let mut has_cycle = false;
-    let mut has_oob = false;
-
-    '_offset_pass: for (&off, &(_name, len, kind)) in functions.iter() {
-        if matches!(kind, DisasmItem::Global) {
-            continue;
-        }
-
-        let prev = *binary;
-
-        binary.take(..off as usize).unwrap();
-
-        let mut label_count = 0;
-        while let Some(&byte) = binary.first() {
-            let offset: i32 = (prev.len() - binary.len()).try_into().unwrap();
-            if offset as u32 == off + len {
-                break;
-            }
-            let Ok(inst) = instr_from_byte(byte) else { break };
-            instrs::parse_args(binary, inst, &mut buf).ok_or(std::io::ErrorKind::OutOfMemory)?;
-
-            for op in buf.drain(..) {
-                let rel = match op {
-                    instrs::Oper::O(rel) => rel,
-                    instrs::Oper::P(rel) => rel.into(),
-                    _ => continue,
-                };
-
-                has_cycle |= rel == 0;
-
-                let global_offset: u32 = (offset + rel).try_into().unwrap();
-                if functions.get(&global_offset).is_some() {
-                    continue;
-                }
-                label_count += labels.try_insert(global_offset, label_count).is_ok() as u32;
-            }
-
-            if matches!(inst, Instr::ECA) {
-                eca_handler(binary);
-            }
-        }
-
-        *binary = prev;
-    }
-
-    let mut ordered = functions.iter().collect::<Vec<_>>();
-    ordered.sort_unstable_by_key(|(_, (name, _, _))| name);
-
-    '_dump: for (&off, &(name, len, kind)) in ordered {
-        if matches!(kind, DisasmItem::Global) {
-            continue;
-        }
-        let prev = *binary;
-
-        writeln!(out, "{name}:")?;
-
-        binary.take(..off as usize).unwrap();
-        while let Some(&byte) = binary.first() {
-            let offset: i32 = (prev.len() - binary.len()).try_into().unwrap();
-            if offset as u32 == off + len {
-                break;
-            }
-            let Ok(inst) = instr_from_byte(byte) else {
-                writeln!(out, "invalid instr {byte}")?;
-                break;
-            };
-            instrs::parse_args(binary, inst, &mut buf).unwrap();
-
-            if let Some(label) = labels.get(&offset.try_into().unwrap()) {
-                write!(out, "{:>2}: ", label)?;
-            } else {
-                write!(out, "    ")?;
-            }
-
-            write!(out, "{inst:<8?} ")?;
-
-            'a: for (i, op) in buf.drain(..).enumerate() {
-                if i != 0 {
-                    write!(out, ", ")?;
-                }
-
-                let rel = 'b: {
-                    match op {
-                        instrs::Oper::O(rel) => break 'b rel,
-                        instrs::Oper::P(rel) => break 'b rel.into(),
-                        instrs::Oper::R(r) => write!(out, "r{r}")?,
-                        instrs::Oper::B(b) => write!(out, "{b}b")?,
-                        instrs::Oper::H(h) => write!(out, "{h}h")?,
-                        instrs::Oper::W(w) => write!(out, "{w}w")?,
-                        instrs::Oper::D(d) if (d as i64) < 0 => write!(out, "{}d", d as i64)?,
-                        instrs::Oper::D(d) => write!(out, "{d}d")?,
-                        instrs::Oper::A(a) => write!(out, "{a}a")?,
-                    }
-
-                    continue 'a;
-                };
-
-                let global_offset: u32 = (offset + rel).try_into().unwrap();
-                if let Some(&(name, ..)) = functions.get(&global_offset) {
-                    if name.contains('\0') {
-                        write!(out, ":{name:?}")?;
-                    } else {
-                        write!(out, ":{name}")?;
-                    }
-                } else {
-                    let local_has_oob = global_offset < off
-                        || global_offset > off + len
-                        || instr_from_byte(prev[global_offset as usize]).is_err()
-                        || prev[global_offset as usize] == 0;
-                    has_oob |= local_has_oob;
-                    let label = labels.get(&global_offset).unwrap();
-                    if local_has_oob {
-                        write!(out, "!!!!!!!!!{rel}")?;
-                    } else {
-                        write!(out, ":{label}")?;
-                    }
-                }
-            }
-
-            writeln!(out)?;
-
-            if matches!(inst, Instr::ECA) {
-                eca_handler(binary);
-            }
-        }
-
-        *binary = prev;
-    }
-
-    if has_oob {
-        return Err(std::io::ErrorKind::InvalidInput.into());
-    }
-
-    if has_cycle {
-        return Err(std::io::ErrorKind::TimedOut.into());
-    }
-
-    Ok(())
-}
-
 struct TaskQueue<T> {
     inner: Mutex<TaskQueueInner<T>>,
 }
diff --git a/hbvm/Cargo.toml b/hbvm/Cargo.toml
index 447ddf2..a6e25b0 100644
--- a/hbvm/Cargo.toml
+++ b/hbvm/Cargo.toml
@@ -9,4 +9,4 @@ alloc   = []
 nightly = []
 
 [dependencies]
-hbbytecode = { path = "../hbbytecode" }
+hbbytecode = { path = "../hbbytecode", default-features = false }
diff --git a/hbvm/src/vmrun.rs b/hbvm/src/vmrun.rs
index e2821f0..8d302d4 100644
--- a/hbvm/src/vmrun.rs
+++ b/hbvm/src/vmrun.rs
@@ -34,7 +34,7 @@ where
     /// Program can return [`VmRunError`] if a trap handling failed
     #[cfg_attr(feature = "nightly", repr(align(4096)))]
     pub fn run(&mut self) -> Result<VmRunOk, VmRunError> {
-        use hbbytecode::opcode::*;
+        use hbbytecode::Instr as I;
         loop {
             // Big match
             //
@@ -56,105 +56,112 @@ where
             // - Yes, we assume you run 64 bit CPU. Else ?conradluget a better CPU
             //   sorry 8 bit fans, HBVM won't run on your Speccy :(
             unsafe {
-                match self.memory.prog_read::<u8>(self.pc as _) {
-                    UN => {
+                match self
+                    .memory
+                    .prog_read::<u8>(self.pc as _)
+                    .try_into()
+                    .map_err(VmRunError::InvalidOpcode)?
+                {
+                    I::UN => {
                         self.bump_pc::<OpsN>();
                         return Err(VmRunError::Unreachable);
                     }
-                    TX => {
+                    I::TX => {
                         self.bump_pc::<OpsN>();
                         return Ok(VmRunOk::End);
                     }
-                    NOP => handler!(self, |OpsN()| ()),
-                    ADD8 => self.binary_op(u8::wrapping_add),
-                    ADD16 => self.binary_op(u16::wrapping_add),
-                    ADD32 => self.binary_op(u32::wrapping_add),
-                    ADD64 => self.binary_op(u64::wrapping_add),
-                    SUB8 => self.binary_op(u8::wrapping_sub),
-                    SUB16 => self.binary_op(u16::wrapping_sub),
-                    SUB32 => self.binary_op(u32::wrapping_sub),
-                    SUB64 => self.binary_op(u64::wrapping_sub),
-                    MUL8 => self.binary_op(u8::wrapping_mul),
-                    MUL16 => self.binary_op(u16::wrapping_mul),
-                    MUL32 => self.binary_op(u32::wrapping_mul),
-                    MUL64 => self.binary_op(u64::wrapping_mul),
-                    AND => self.binary_op::<u64>(ops::BitAnd::bitand),
-                    OR => self.binary_op::<u64>(ops::BitOr::bitor),
-                    XOR => self.binary_op::<u64>(ops::BitXor::bitxor),
-                    SLU8 => self.binary_op_shift::<u8>(u8::wrapping_shl),
-                    SLU16 => self.binary_op_shift::<u16>(u16::wrapping_shl),
-                    SLU32 => self.binary_op_shift::<u32>(u32::wrapping_shl),
-                    SLU64 => self.binary_op_shift::<u64>(u64::wrapping_shl),
-                    SRU8 => self.binary_op_shift::<u8>(u8::wrapping_shr),
-                    SRU16 => self.binary_op_shift::<u16>(u16::wrapping_shr),
-                    SRU32 => self.binary_op_shift::<u32>(u32::wrapping_shr),
-                    SRU64 => self.binary_op_shift::<u64>(u64::wrapping_shr),
-                    SRS8 => self.binary_op_shift::<i8>(i8::wrapping_shr),
-                    SRS16 => self.binary_op_shift::<i16>(i16::wrapping_shr),
-                    SRS32 => self.binary_op_shift::<i32>(i32::wrapping_shr),
-                    SRS64 => self.binary_op_shift::<i64>(i64::wrapping_shr),
-                    CMPU => handler!(self, |OpsRRR(tg, a0, a1)| self.cmp(
+                    I::NOP => handler!(self, |OpsN()| ()),
+                    I::ADD8 => self.binary_op(u8::wrapping_add),
+                    I::ADD16 => self.binary_op(u16::wrapping_add),
+                    I::ADD32 => self.binary_op(u32::wrapping_add),
+                    I::ADD64 => self.binary_op(u64::wrapping_add),
+                    I::SUB8 => self.binary_op(u8::wrapping_sub),
+                    I::SUB16 => self.binary_op(u16::wrapping_sub),
+                    I::SUB32 => self.binary_op(u32::wrapping_sub),
+                    I::SUB64 => self.binary_op(u64::wrapping_sub),
+                    I::MUL8 => self.binary_op(u8::wrapping_mul),
+                    I::MUL16 => self.binary_op(u16::wrapping_mul),
+                    I::MUL32 => self.binary_op(u32::wrapping_mul),
+                    I::MUL64 => self.binary_op(u64::wrapping_mul),
+                    I::AND => self.binary_op::<u64>(ops::BitAnd::bitand),
+                    I::OR => self.binary_op::<u64>(ops::BitOr::bitor),
+                    I::XOR => self.binary_op::<u64>(ops::BitXor::bitxor),
+                    I::SLU8 => self.binary_op_shift::<u8>(u8::wrapping_shl),
+                    I::SLU16 => self.binary_op_shift::<u16>(u16::wrapping_shl),
+                    I::SLU32 => self.binary_op_shift::<u32>(u32::wrapping_shl),
+                    I::SLU64 => self.binary_op_shift::<u64>(u64::wrapping_shl),
+                    I::SRU8 => self.binary_op_shift::<u8>(u8::wrapping_shr),
+                    I::SRU16 => self.binary_op_shift::<u16>(u16::wrapping_shr),
+                    I::SRU32 => self.binary_op_shift::<u32>(u32::wrapping_shr),
+                    I::SRU64 => self.binary_op_shift::<u64>(u64::wrapping_shr),
+                    I::SRS8 => self.binary_op_shift::<i8>(i8::wrapping_shr),
+                    I::SRS16 => self.binary_op_shift::<i16>(i16::wrapping_shr),
+                    I::SRS32 => self.binary_op_shift::<i32>(i32::wrapping_shr),
+                    I::SRS64 => self.binary_op_shift::<i64>(i64::wrapping_shr),
+                    I::CMPU => handler!(self, |OpsRRR(tg, a0, a1)| self.cmp(
                         tg,
                         a0,
                         self.read_reg(a1).cast::<u64>()
                     )),
-                    CMPS => handler!(self, |OpsRRR(tg, a0, a1)| self.cmp(
+                    I::CMPS => handler!(self, |OpsRRR(tg, a0, a1)| self.cmp(
                         tg,
                         a0,
                         self.read_reg(a1).cast::<i64>()
                     )),
-                    DIRU8 => self.dir::<u8>(),
-                    DIRU16 => self.dir::<u16>(),
-                    DIRU32 => self.dir::<u32>(),
-                    DIRU64 => self.dir::<u64>(),
-                    DIRS8 => self.dir::<i8>(),
-                    DIRS16 => self.dir::<i16>(),
-                    DIRS32 => self.dir::<i32>(),
-                    DIRS64 => self.dir::<i64>(),
-                    NEG => handler!(self, |OpsRR(tg, a0)| {
+                    I::DIRU8 => self.dir::<u8>(),
+                    I::DIRU16 => self.dir::<u16>(),
+                    I::DIRU32 => self.dir::<u32>(),
+                    I::DIRU64 => self.dir::<u64>(),
+                    I::DIRS8 => self.dir::<i8>(),
+                    I::DIRS16 => self.dir::<i16>(),
+                    I::DIRS32 => self.dir::<i32>(),
+                    I::DIRS64 => self.dir::<i64>(),
+                    I::NEG => handler!(self, |OpsRR(tg, a0)| {
                         // Bit negation
                         self.write_reg(tg, self.read_reg(a0).cast::<u64>().wrapping_neg())
                     }),
-                    NOT => handler!(self, |OpsRR(tg, a0)| {
+                    I::NOT => handler!(self, |OpsRR(tg, a0)| {
                         // Logical negation
                         self.write_reg(tg, u64::from(self.read_reg(a0).cast::<u64>() == 0));
                     }),
-                    SXT8 => handler!(self, |OpsRR(tg, a0)| {
+                    I::SXT8 => handler!(self, |OpsRR(tg, a0)| {
                         self.write_reg(tg, self.read_reg(a0).cast::<i8>() as i64)
                     }),
-                    SXT16 => handler!(self, |OpsRR(tg, a0)| {
+                    I::SXT16 => handler!(self, |OpsRR(tg, a0)| {
                         self.write_reg(tg, self.read_reg(a0).cast::<i16>() as i64)
                     }),
-                    SXT32 => handler!(self, |OpsRR(tg, a0)| {
+                    I::SXT32 => handler!(self, |OpsRR(tg, a0)| {
                         self.write_reg(tg, self.read_reg(a0).cast::<i32>() as i64)
                     }),
-                    ADDI8 => self.binary_op_imm(u8::wrapping_add),
-                    ADDI16 => self.binary_op_imm(u16::wrapping_add),
-                    ADDI32 => self.binary_op_imm(u32::wrapping_add),
-                    ADDI64 => self.binary_op_imm(u64::wrapping_add),
-                    MULI8 => self.binary_op_imm(u8::wrapping_mul),
-                    MULI16 => self.binary_op_imm(u16::wrapping_mul),
-                    MULI32 => self.binary_op_imm(u32::wrapping_mul),
-                    MULI64 => self.binary_op_imm(u64::wrapping_mul),
-                    ANDI => self.binary_op_imm::<u64>(ops::BitAnd::bitand),
-                    ORI => self.binary_op_imm::<u64>(ops::BitOr::bitor),
-                    XORI => self.binary_op_imm::<u64>(ops::BitXor::bitxor),
-                    SLUI8 => self.binary_op_ims::<u8>(u8::wrapping_shl),
-                    SLUI16 => self.binary_op_ims::<u16>(u16::wrapping_shl),
-                    SLUI32 => self.binary_op_ims::<u32>(u32::wrapping_shl),
-                    SLUI64 => self.binary_op_ims::<u64>(u64::wrapping_shl),
-                    SRUI8 => self.binary_op_ims::<u8>(u8::wrapping_shr),
-                    SRUI16 => self.binary_op_ims::<u16>(u16::wrapping_shr),
-                    SRUI32 => self.binary_op_ims::<u32>(u32::wrapping_shr),
-                    SRUI64 => self.binary_op_ims::<u64>(u64::wrapping_shr),
-                    SRSI8 => self.binary_op_ims::<i8>(i8::wrapping_shr),
-                    SRSI16 => self.binary_op_ims::<i16>(i16::wrapping_shr),
-                    SRSI32 => self.binary_op_ims::<i32>(i32::wrapping_shr),
-                    SRSI64 => self.binary_op_ims::<i64>(i64::wrapping_shr),
-                    CMPUI => handler!(self, |OpsRRD(tg, a0, imm)| { self.cmp(tg, a0, imm) }),
-                    CMPSI => handler!(self, |OpsRRD(tg, a0, imm)| { self.cmp(tg, a0, imm as i64) }),
-                    CP => handler!(self, |OpsRR(tg, a0)| self.write_reg(tg, self.read_reg(a0))),
-                    SWA => handler!(self, |OpsRR(r0, r1)| {
+                    I::ADDI8 => self.binary_op_imm(u8::wrapping_add),
+                    I::ADDI16 => self.binary_op_imm(u16::wrapping_add),
+                    I::ADDI32 => self.binary_op_imm(u32::wrapping_add),
+                    I::ADDI64 => self.binary_op_imm(u64::wrapping_add),
+                    I::MULI8 => self.binary_op_imm(u8::wrapping_mul),
+                    I::MULI16 => self.binary_op_imm(u16::wrapping_mul),
+                    I::MULI32 => self.binary_op_imm(u32::wrapping_mul),
+                    I::MULI64 => self.binary_op_imm(u64::wrapping_mul),
+                    I::ANDI => self.binary_op_imm::<u64>(ops::BitAnd::bitand),
+                    I::ORI => self.binary_op_imm::<u64>(ops::BitOr::bitor),
+                    I::XORI => self.binary_op_imm::<u64>(ops::BitXor::bitxor),
+                    I::SLUI8 => self.binary_op_ims::<u8>(u8::wrapping_shl),
+                    I::SLUI16 => self.binary_op_ims::<u16>(u16::wrapping_shl),
+                    I::SLUI32 => self.binary_op_ims::<u32>(u32::wrapping_shl),
+                    I::SLUI64 => self.binary_op_ims::<u64>(u64::wrapping_shl),
+                    I::SRUI8 => self.binary_op_ims::<u8>(u8::wrapping_shr),
+                    I::SRUI16 => self.binary_op_ims::<u16>(u16::wrapping_shr),
+                    I::SRUI32 => self.binary_op_ims::<u32>(u32::wrapping_shr),
+                    I::SRUI64 => self.binary_op_ims::<u64>(u64::wrapping_shr),
+                    I::SRSI8 => self.binary_op_ims::<i8>(i8::wrapping_shr),
+                    I::SRSI16 => self.binary_op_ims::<i16>(i16::wrapping_shr),
+                    I::SRSI32 => self.binary_op_ims::<i32>(i32::wrapping_shr),
+                    I::SRSI64 => self.binary_op_ims::<i64>(i64::wrapping_shr),
+                    I::CMPUI => handler!(self, |OpsRRD(tg, a0, imm)| { self.cmp(tg, a0, imm) }),
+                    I::CMPSI => {
+                        handler!(self, |OpsRRD(tg, a0, imm)| { self.cmp(tg, a0, imm as i64) })
+                    }
+                    I::CP => handler!(self, |OpsRR(tg, a0)| self.write_reg(tg, self.read_reg(a0))),
+                    I::SWA => handler!(self, |OpsRR(r0, r1)| {
                         // Swap registers
                         match (r0, r1) {
                             (0, 0) => (),
@@ -167,33 +174,33 @@ where
                             }
                         }
                     }),
-                    LI8 => handler!(self, |OpsRB(tg, imm)| self.write_reg(tg, imm)),
-                    LI16 => handler!(self, |OpsRH(tg, imm)| self.write_reg(tg, imm)),
-                    LI32 => handler!(self, |OpsRW(tg, imm)| self.write_reg(tg, imm)),
-                    LI64 => handler!(self, |OpsRD(tg, imm)| self.write_reg(tg, imm)),
-                    LRA => handler!(self, |OpsRRO(tg, reg, off)| self.write_reg(
+                    I::LI8 => handler!(self, |OpsRB(tg, imm)| self.write_reg(tg, imm)),
+                    I::LI16 => handler!(self, |OpsRH(tg, imm)| self.write_reg(tg, imm)),
+                    I::LI32 => handler!(self, |OpsRW(tg, imm)| self.write_reg(tg, imm)),
+                    I::LI64 => handler!(self, |OpsRD(tg, imm)| self.write_reg(tg, imm)),
+                    I::LRA => handler!(self, |OpsRRO(tg, reg, off)| self.write_reg(
                         tg,
                         self.pcrel(off).wrapping_add(self.read_reg(reg).cast::<i64>()).get(),
                     )),
                     // Load. If loading more than register size, continue on adjecent registers
-                    LD => handler!(self, |OpsRRAH(dst, base, off, count)| self
+                    I::LD => handler!(self, |OpsRRAH(dst, base, off, count)| self
                         .load(dst, base, off, count)?),
                     // Store. Same rules apply as to LD
-                    ST => handler!(self, |OpsRRAH(dst, base, off, count)| self
+                    I::ST => handler!(self, |OpsRRAH(dst, base, off, count)| self
                         .store(dst, base, off, count)?),
-                    LDR => handler!(self, |OpsRROH(dst, base, off, count)| self.load(
+                    I::LDR => handler!(self, |OpsRROH(dst, base, off, count)| self.load(
                         dst,
                         base,
                         self.pcrel(off).get(),
                         count
                     )?),
-                    STR => handler!(self, |OpsRROH(dst, base, off, count)| self.store(
+                    I::STR => handler!(self, |OpsRROH(dst, base, off, count)| self.store(
                         dst,
                         base,
                         self.pcrel(off).get(),
                         count
                     )?),
-                    BMC => {
+                    I::BMC => {
                         // Block memory copy
                         match if let Some(copier) = &mut self.copier {
                             // There is some copier, poll.
@@ -227,7 +234,7 @@ where
                             core::task::Poll::Pending => (),
                         }
                     }
-                    BRC => handler!(self, |OpsRRB(src, dst, count)| {
+                    I::BRC => handler!(self, |OpsRRB(src, dst, count)| {
                         // Block register copy
                         if src.checked_add(count).is_none() || dst.checked_add(count).is_none() {
                             return Err(VmRunError::RegOutOfBounds);
@@ -239,11 +246,11 @@ where
                             usize::from(count),
                         );
                     }),
-                    JMP => {
+                    I::JMP => {
                         let OpsO(off) = self.decode();
                         self.pc = self.pc.wrapping_add(off);
                     }
-                    JAL => {
+                    I::JAL => {
                         // Jump and link. Save PC after this instruction to
                         // specified register and jump to reg + relative offset.
                         let OpsRRO(save, reg, offset) = self.decode();
@@ -251,7 +258,7 @@ where
                         self.write_reg(save, self.pc.next::<OpsRRO>());
                         self.pc = self.pcrel(offset).wrapping_add(self.read_reg(reg).cast::<i64>());
                     }
-                    JALA => {
+                    I::JALA => {
                         // Jump and link. Save PC after this instruction to
                         // specified register and jump to reg
                         let OpsRRA(save, reg, offset) = self.decode();
@@ -261,8 +268,8 @@ where
                             Address::new(self.read_reg(reg).cast::<u64>().wrapping_add(offset));
                     }
                     // Conditional jumps, jump only to immediates
-                    JEQ => self.cond_jmp::<u64>(Ordering::Equal),
-                    JNE => {
+                    I::JEQ => self.cond_jmp::<u64>(Ordering::Equal),
+                    I::JNE => {
                         let OpsRRP(a0, a1, ja) = self.decode();
                         if self.read_reg(a0).cast::<u64>() != self.read_reg(a1).cast::<u64>() {
                             self.pc = self.pcrel(ja);
@@ -270,11 +277,11 @@ where
                             self.bump_pc::<OpsRRP>();
                         }
                     }
-                    JLTS => self.cond_jmp::<i64>(Ordering::Less),
-                    JGTS => self.cond_jmp::<i64>(Ordering::Greater),
-                    JLTU => self.cond_jmp::<u64>(Ordering::Less),
-                    JGTU => self.cond_jmp::<u64>(Ordering::Greater),
-                    ECA => {
+                    I::JLTS => self.cond_jmp::<i64>(Ordering::Less),
+                    I::JGTS => self.cond_jmp::<i64>(Ordering::Greater),
+                    I::JLTU => self.cond_jmp::<u64>(Ordering::Less),
+                    I::JGTU => self.cond_jmp::<u64>(Ordering::Greater),
+                    I::ECA => {
                         // So we don't get timer interrupt after ECALL
                         if TIMER_QUOTIENT != 0 {
                             self.timer = self.timer.wrapping_add(1);
@@ -283,33 +290,33 @@ where
                         self.bump_pc::<OpsN>();
                         return Ok(VmRunOk::Ecall);
                     }
-                    EBP => {
+                    I::EBP => {
                         self.bump_pc::<OpsN>();
                         return Ok(VmRunOk::Breakpoint);
                     }
-                    FADD32 => self.binary_op::<f32>(ops::Add::add),
-                    FADD64 => self.binary_op::<f64>(ops::Add::add),
-                    FSUB32 => self.binary_op::<f32>(ops::Sub::sub),
-                    FSUB64 => self.binary_op::<f64>(ops::Sub::sub),
-                    FMUL32 => self.binary_op::<f32>(ops::Mul::mul),
-                    FMUL64 => self.binary_op::<f64>(ops::Mul::mul),
-                    FDIV32 => self.binary_op::<f32>(ops::Div::div),
-                    FDIV64 => self.binary_op::<f64>(ops::Div::div),
-                    FMA32 => self.fma::<f32>(),
-                    FMA64 => self.fma::<f64>(),
-                    FINV32 => handler!(self, |OpsRR(tg, reg)| self
+                    I::FADD32 => self.binary_op::<f32>(ops::Add::add),
+                    I::FADD64 => self.binary_op::<f64>(ops::Add::add),
+                    I::FSUB32 => self.binary_op::<f32>(ops::Sub::sub),
+                    I::FSUB64 => self.binary_op::<f64>(ops::Sub::sub),
+                    I::FMUL32 => self.binary_op::<f32>(ops::Mul::mul),
+                    I::FMUL64 => self.binary_op::<f64>(ops::Mul::mul),
+                    I::FDIV32 => self.binary_op::<f32>(ops::Div::div),
+                    I::FDIV64 => self.binary_op::<f64>(ops::Div::div),
+                    I::FMA32 => self.fma::<f32>(),
+                    I::FMA64 => self.fma::<f64>(),
+                    I::FINV32 => handler!(self, |OpsRR(tg, reg)| self
                         .write_reg(tg, 1. / self.read_reg(reg).cast::<f32>())),
-                    FINV64 => handler!(self, |OpsRR(tg, reg)| self
+                    I::FINV64 => handler!(self, |OpsRR(tg, reg)| self
                         .write_reg(tg, 1. / self.read_reg(reg).cast::<f64>())),
-                    FCMPLT32 => self.fcmp::<f32>(Ordering::Less),
-                    FCMPLT64 => self.fcmp::<f64>(Ordering::Less),
-                    FCMPGT32 => self.fcmp::<f32>(Ordering::Greater),
-                    FCMPGT64 => self.fcmp::<f64>(Ordering::Greater),
-                    ITF32 => handler!(self, |OpsRR(tg, reg)| self
+                    I::FCMPLT32 => self.fcmp::<f32>(Ordering::Less),
+                    I::FCMPLT64 => self.fcmp::<f64>(Ordering::Less),
+                    I::FCMPGT32 => self.fcmp::<f32>(Ordering::Greater),
+                    I::FCMPGT64 => self.fcmp::<f64>(Ordering::Greater),
+                    I::ITF32 => handler!(self, |OpsRR(tg, reg)| self
                         .write_reg(tg, self.read_reg(reg).cast::<i64>() as f32)),
-                    ITF64 => handler!(self, |OpsRR(tg, reg)| self
+                    I::ITF64 => handler!(self, |OpsRR(tg, reg)| self
                         .write_reg(tg, self.read_reg(reg).cast::<i64>() as f64)),
-                    FTI32 => handler!(self, |OpsRRB(tg, reg, mode)| self.write_reg(
+                    I::FTI32 => handler!(self, |OpsRRB(tg, reg, mode)| self.write_reg(
                         tg,
                         crate::float::f32toint(
                             self.read_reg(reg).cast::<f32>(),
@@ -317,7 +324,7 @@ where
                                 .map_err(|()| VmRunError::InvalidOperand)?,
                         ),
                     )),
-                    FTI64 => handler!(self, |OpsRRB(tg, reg, mode)| self.write_reg(
+                    I::FTI64 => handler!(self, |OpsRRB(tg, reg, mode)| self.write_reg(
                         tg,
                         crate::float::f64toint(
                             self.read_reg(reg).cast::<f64>(),
@@ -325,9 +332,9 @@ where
                                 .map_err(|()| VmRunError::InvalidOperand)?,
                         ),
                     )),
-                    FC32T64 => handler!(self, |OpsRR(tg, reg)| self
+                    I::FC32T64 => handler!(self, |OpsRR(tg, reg)| self
                         .write_reg(tg, self.read_reg(reg).cast::<f32>() as f64)),
-                    FC64T32 => handler!(self, |OpsRRB(tg, reg, mode)| self.write_reg(
+                    I::FC64T32 => handler!(self, |OpsRRB(tg, reg, mode)| self.write_reg(
                         tg,
                         crate::float::conv64to32(
                             self.read_reg(reg).cast(),
@@ -335,27 +342,26 @@ where
                                 .map_err(|()| VmRunError::InvalidOperand)?,
                         ),
                     )),
-                    LRA16 => handler!(self, |OpsRRP(tg, reg, imm)| self.write_reg(
+                    I::LRA16 => handler!(self, |OpsRRP(tg, reg, imm)| self.write_reg(
                         tg,
                         (self.pc + self.read_reg(reg).cast::<u64>() + imm + 3_u16).get(),
                     )),
-                    LDR16 => handler!(self, |OpsRRPH(dst, base, off, count)| self.load(
+                    I::LDR16 => handler!(self, |OpsRRPH(dst, base, off, count)| self.load(
                         dst,
                         base,
                         self.pcrel(off).get(),
                         count
                     )?),
-                    STR16 => handler!(self, |OpsRRPH(dst, base, off, count)| self.store(
+                    I::STR16 => handler!(self, |OpsRRPH(dst, base, off, count)| self.store(
                         dst,
                         base,
                         self.pcrel(off).get(),
                         count
                     )?),
-                    JMP16 => {
+                    I::JMP16 => {
                         let OpsP(off) = self.decode();
                         self.pc = self.pcrel(off);
                     }
-                    op => return Err(VmRunError::InvalidOpcode(op)),
                 }
             }