diff --git a/src/arch/x86_64/compile.rs b/src/arch/x86_64/compile.rs
index 8ed4591..a28ae45 100644
--- a/src/arch/x86_64/compile.rs
+++ b/src/arch/x86_64/compile.rs
@@ -1,14 +1,15 @@
 use std::collections::{HashMap, HashSet, VecDeque};
 
 use super::*;
-use crate::backend::{Body, LibImport, LinkedProgram, SymImport, SymTable, Symbol, VarId};
+use crate::backend::{Body, Func, LibImport, LinkedProgram, SymImport, SymTable, Symbol, VarId};
 
 pub struct Encoder<'a> {
     pub code: Code,
     pub sym_tab: SymTable<u64>,
     pub sym_refs: HashMap<Symbol, Vec<usize>>,
     pub program: &'a Program<X86_64>,
-    pub vars: VarMap,
+    pub segs: Vec<SegUses>,
+    pub vars: HashMap<VarId, Reg>,
 }
 
 pub fn compile(p: &Program<X86_64>) -> Result<LinkedProgram<u64>, CompilerMsg> {
@@ -17,18 +18,7 @@ pub fn compile(p: &Program<X86_64>) -> Result<LinkedProgram<u64>, CompilerMsg> {
     p.encode_data(&mut encoder.code.bytes, &mut encoder.sym_tab);
 
     for f in &p.funcs {
-        let addr = encoder.code.bytes.len();
-        encoder.sym_tab.insert(f.sym, addr as u64);
-        let mut segments = Vec::new();
-        calc_uses(&mut segments, &f.body, p);
-    }
-
-    for f in &p.funcs {
-        let addr = encoder.code.bytes.len();
-        encoder.sym_tab.insert(f.sym, addr as u64);
-        for instr in &f.body {
-            encoder.compile_instr(instr)?;
-        }
+        encoder.func(f);
     }
 
     for (pos, sym) in encoder.code.missing.drain(..) {
@@ -80,133 +70,143 @@ pub struct RegUse {
     var: Option<VarId>,
 }
 
-pub fn calc_uses(
-    segments: &mut Vec<SegUses>,
-    body: &Body<X86_64>,
-    p: &Program<X86_64>,
-) -> (usize, usize) {
-    let mut pos = 0;
-    let seg_i = segments.len();
-    segments.push(Default::default());
-    let mut uses = SegUses::default();
-    macro_rules! push {
-        ($var:ident) => {
-            push!($var, 0)
-        };
-        ($var:ident, $pos:expr) => {
-            uses.var
-                .entry($var.clone())
-                .or_default()
-                .push_back(pos + $pos)
-        };
-    }
-    for instr in body {
-        match instr {
-            BInstr::Set { dst, src: _ } => push!(dst),
-            BInstr::Call { dst, f, args } => {
-                let conv = &p.call_convs[p.funcs[f].conv];
-                push!(dst);
-
-                for &reg in conv.scratch() {
-                    uses.reg[reg as usize].push_back(RegUse { pos, var: None });
-                }
-                for (i, &arg) in args.iter().enumerate() {
-                    push!(arg);
-                    if let Some(&reg) = conv.param().get(i) {
-                        uses.reg[reg as usize].back_mut().unwrap().var = Some(arg);
-                    }
-                }
-            }
-            BInstr::Copy { dst, src } => {
-                push!(dst);
-                push!(src);
-            }
-            BInstr::Add { dst, src1, src2 } => {
-                push!(dst);
-                push!(src1);
-                push!(src2);
-            }
-            BInstr::If { cond, then, else_ } => {
-                push!(cond);
-                pos += 1;
-                let (seg_i1, len1) = calc_uses(segments, then, p);
-                let (seg_i2, len2) = calc_uses(segments, else_, p);
-                // insert closest usages
-                for (var, poss1) in &segments[seg_i1].var {
-                    if let Some(poss2) = segments[seg_i2].var.get(var) {
-                        push!(var, poss1[0].min(poss2[0]));
-                    } else {
-                        push!(var, poss1[0]);
-                    }
-                }
-                for (var, poss2) in &segments[seg_i2].var {
-                    if !segments[seg_i1].var.contains_key(var) {
-                        push!(var, poss2[0]);
-                    }
-                }
-                pos += len1.max(len2);
-                continue;
-            }
-            BInstr::Loop(instrs) => {
-                let (seg_i2, len) = calc_uses(segments, instrs, p);
-                // insert closest usages
-                for (var, poss) in &segments[seg_i2].var {
-                    push!(var, poss[0]);
-                }
-                // during register allocation, want to insert the first use of each var
-                // at len + use, because if it jumps back up, that will be the next
-                // usage rather than if the loop exits; pad ensures there is room so
-                // the insertions are always before the rest of the usages (after loop)
-                let pad = (len * 2).saturating_sub(pos);
-                pos += len + pad;
-                continue;
-            }
-            BInstr::Break(var) => {
-                if let Some(var) = var {
-                    push!(var);
-                }
-            }
-            BInstr::Return(var) => {
-                if let Some(var) = var {
-                    push!(var);
-                }
-            }
-            BInstr::Asm(asm) => {
-                let mut used = HashSet::new();
-                for i in &asm.instrs {
-                    if let Some(reg) = i.dst_reg() {
-                        used.insert(reg.reg());
-                    }
-                }
-                for &(reg, var) in &asm.args {
-                    push!(var);
-                    used.remove(&reg);
-                    uses.reg[reg as usize].push_back(RegUse {
-                        pos,
-                        var: Some(var),
-                    });
-                }
-                for reg in used {
-                    uses.reg[reg as usize].push_back(RegUse { pos, var: None });
-                }
-            }
-        }
-        pos += 1;
-    }
-    segments[seg_i] = uses;
-    return (seg_i, pos);
-}
-
 type BInstr = crate::backend::Instr<X86_64>;
 impl<'a> Encoder<'a> {
-    fn compile_instr(&mut self, instr: &BInstr) -> EncodeRes {
-        match instr {
-            BInstr::Asm(asm) => self.asm(asm)?,
-            _ => todo!(),
+    fn func(&mut self, f: &Func<X86_64>) -> EncodeRes {
+        let addr = self.code.bytes.len();
+        self.sym_tab.insert(f.sym, addr as u64);
+        self.segs.clear();
+        self.calc_uses(&f.body);
+        for instr in &f.body {
+            match instr {
+                BInstr::Asm(asm) => self.asm(asm)?,
+                _ => todo!(),
+            }
         }
         Ok(())
     }
 
+    pub fn calc_uses(&mut self, body: &Body<X86_64>) -> (usize, usize) {
+        let mut pos = 0;
+        let seg_i = self.segs.len();
+        self.segs.push(Default::default());
+        let mut uses = SegUses::default();
+        macro_rules! push {
+            ($var:ident) => {
+                push!($var, 0)
+            };
+            ($var:ident, $pos:expr) => {
+                uses.var
+                    .entry($var.clone())
+                    .or_default()
+                    .push_back(pos + $pos)
+            };
+        }
+        for instr in body {
+            match instr {
+                BInstr::Set { dst, src: _ } => push!(dst),
+                BInstr::Call { dst, f, args } => {
+                    let conv = &self.program.call_convs[self.program.funcs[f].conv];
+                    push!(dst);
+
+                    for &reg in conv.scratch() {
+                        uses.reg[reg as usize].push_back(RegUse { pos, var: None });
+                    }
+                    for (i, &arg) in args.iter().enumerate() {
+                        push!(arg);
+                        if let Some(&reg) = conv.param().get(i) {
+                            uses.reg[reg as usize].back_mut().unwrap().var = Some(arg);
+                        }
+                    }
+                }
+                BInstr::Copy { dst, src } => {
+                    push!(dst);
+                    push!(src);
+                }
+                BInstr::Add { dst, src1, src2 } => {
+                    push!(dst);
+                    push!(src1);
+                    push!(src2);
+                }
+                BInstr::If { cond, then, else_ } => {
+                    push!(cond);
+                    pos += 1;
+                    let (seg_i1, len1) = self.calc_uses(then);
+                    let (seg_i2, len2) = self.calc_uses(else_);
+                    // insert closest usages
+                    for (var, poss1) in &self.segs[seg_i1].var {
+                        if let Some(poss2) = self.segs[seg_i2].var.get(var) {
+                            push!(var, poss1[0].min(poss2[0]));
+                        } else {
+                            push!(var, poss1[0]);
+                        }
+                    }
+                    for (var, poss2) in &self.segs[seg_i2].var {
+                        if !self.segs[seg_i1].var.contains_key(var) {
+                            push!(var, poss2[0]);
+                        }
+                    }
+                    pos += len1.max(len2);
+                    continue;
+                }
+                BInstr::Loop(instrs) => {
+                    let (seg_i2, len) = self.calc_uses(instrs);
+                    // insert closest usages
+                    for (var, poss) in &self.segs[seg_i2].var {
+                        push!(var, poss[0]);
+                    }
+                    // during register allocation, want to insert the first use of each var
+                    // at len + use, because if it jumps back up, that will be the next
+                    // usage rather than if the loop exits; pad ensures there is room so
+                    // the insertions are always before the rest of the usages (after loop)
+                    let pad = (len * 2).saturating_sub(pos);
+                    pos += len + pad;
+                    continue;
+                }
+                BInstr::Break(var) => {
+                    if let Some(var) = var {
+                        push!(var);
+                    }
+                }
+                BInstr::Return(var) => {
+                    if let Some(var) = var {
+                        push!(var);
+                    }
+                }
+                BInstr::Asm(asm) => {
+                    let mut used = HashSet::new();
+                    for i in &asm.instrs {
+                        if let Some(reg) = i.dst_reg() {
+                            used.insert(reg.reg());
+                        }
+                    }
+                    for &(reg, var) in &asm.args {
+                        push!(var);
+                        used.remove(&reg);
+                        uses.reg[reg as usize].push_back(RegUse {
+                            pos,
+                            var: Some(var),
+                        });
+                    }
+                    for reg in used {
+                        uses.reg[reg as usize].push_back(RegUse { pos, var: None });
+                    }
+                }
+            }
+            pos += 1;
+        }
+        self.segs[seg_i] = uses;
+        return (seg_i, pos);
+    }
+
+    pub fn rvm(&mut self, input: Rvm) -> RegMemKind {
+        match input {
+            Rvm::Reg(reg) => reg,
+            Rvm::Var(var_id) => todo!(),
+            Rvm::Mem(mem) => todo!(),
+        }
+    }
+
     pub fn asm(&mut self, asm: &Asm) -> EncodeRes {
         let mut used = HashSet::default();
         let mut vars = HashSet::default();
@@ -218,9 +218,9 @@ impl<'a> Encoder<'a> {
                 vars.insert(var);
             }
         }
-        let overlap = used.intersection(&self.vars.active.values());
+        let overlap = used.intersection(&self.vars.values());
         for var in &vars {
-            if let Some(reg) = self.vars.active.get(var)
+            if let Some(reg) = self.vars.get(var)
                 && used.contains(reg)
             {}
         }
@@ -247,20 +247,8 @@ impl<'a> Encoder<'a> {
             code: Code::default(),
             sym_tab: SymTable::new(program.sym_count()),
             sym_refs: Default::default(),
-            vars: VarMap::default(),
+            segs: Default::default(),
             program,
         }
     }
 }
-
-pub struct VarMap {
-    active: HashMap<VarId, Reg>,
-}
-
-impl Default for VarMap {
-    fn default() -> Self {
-        Self {
-            active: Default::default(),
-        }
-    }
-}
diff --git a/src/arch/x86_64/encode.rs b/src/arch/x86_64/encode.rs
index 9ef3d00..34f6ee2 100644
--- a/src/arch/x86_64/encode.rs
+++ b/src/arch/x86_64/encode.rs
@@ -11,9 +11,10 @@ pub struct Code {
 }
 
 impl Code {
-    pub fn mov(&mut self, dst: impl RegMem, src: impl Into<RegMemImm>) -> EncodeRes {
+    pub fn mov(&mut self, dst: impl Into<RegMemKind>, src: impl Into<RegMemImm>) -> EncodeRes {
         let src = src.into();
-        match dst.kind() {
+        let dst = dst.into();
+        match dst {
             RegMemKind::Reg(mut dst) => match src {
                 RegMemImm::Reg(src) => {
                     if dst.width() != src.width() {
@@ -162,7 +163,13 @@ impl Code {
         self.bytes.push(0xc3);
     }
 
-    fn add_sub(&mut self, dst: impl RegMem, src: impl Into<RegMemImm>, ext: u8) -> EncodeRes {
+    fn add_sub(
+        &mut self,
+        dst: impl Into<RegMemKind>,
+        src: impl Into<RegMemImm>,
+        ext: u8,
+    ) -> EncodeRes {
+        let dst = dst.into();
         match src.into() {
             RegMemImm::Reg(src) => {
                 if src.width() != dst.width() {
@@ -219,11 +226,11 @@ impl Code {
         Ok(())
     }
 
-    pub fn add(&mut self, dst: impl RegMem, src: impl Into<RegMemImm>) -> EncodeRes {
+    pub fn add(&mut self, dst: impl Into<RegMemKind>, src: impl Into<RegMemImm>) -> EncodeRes {
         self.add_sub(dst, src, 0)
     }
 
-    pub fn sub(&mut self, dst: impl RegMem, src: impl Into<RegMemImm>) -> EncodeRes {
+    pub fn sub(&mut self, dst: impl Into<RegMemKind>, src: impl Into<RegMemImm>) -> EncodeRes {
         self.add_sub(dst, src, 5)
     }
 
diff --git a/src/arch/x86_64/types/arg.rs b/src/arch/x86_64/types/arg.rs
index 632919c..7cdd04d 100644
--- a/src/arch/x86_64/types/arg.rs
+++ b/src/arch/x86_64/types/arg.rs
@@ -1,11 +1,6 @@
 use super::*;
 use crate::backend::Symbol;
 
-pub trait RegMem: RexBit + RexW + ModRMRM + Copy + MaybeMem {
-    fn width(&self) -> Width;
-    fn kind(self) -> RegMemKind;
-}
-
 #[derive(Clone, Copy)]
 pub enum RegMemKind {
     Reg(RegW),
@@ -23,12 +18,12 @@ pub trait MaybeMem {
     fn mem(&self) -> Option<Mem>;
 }
 
-impl RegMem for RegW {
-    fn width(&self) -> Width {
-        self.width()
-    }
-    fn kind(self) -> RegMemKind {
-        RegMemKind::Reg(self)
+impl RegMemKind {
+    pub fn width(&self) -> Width {
+        match self {
+            RegMemKind::Reg(reg) => reg.width(),
+            RegMemKind::Mem(mem) => todo!(),
+        }
     }
 }