From 9ec9b5a22a03d126795e36c3aa288be5d7ea03f2 Mon Sep 17 00:00:00 2001
From: water <awaterford111445@gmail.com>
Date: Sun, 13 Sep 2020 17:34:02 -0400
Subject: [PATCH] add conditional stuff

---
 game/overlord/iso.cpp                      |   5 +-
 goal_src/goal-lib.gc                       |  58 ++++++
 goal_src/kernel-defs.gc                    |   2 +-
 goal_src/kernel/gcommon.gc                 |  72 ++++++-
 goal_src/test/test-build-game.gc           |   6 +-
 goal_src/test/test-defsmacro-defgmacro.gc  |  13 ++
 goal_src/test/test-desfun.gc               |  10 +
 goal_src/test/test-div-1.gc                |   1 +
 goal_src/test/test-div-2.gc                |   3 +
 goal_src/test/test-factorial-loop.gc       |  11 +
 goal_src/test/test-factorial-recursive.gc  |  12 ++
 goal_src/test/test-mlet.gc                 |   7 +
 goal_src/test/test-protect.gc              |  15 ++
 goal_src/test/test-set-symbol.gc           |  18 ++
 goal_src/test/test-three-reg-add.gc        |   3 +
 goal_src/test/test-three-reg-mult.gc       |   6 +
 goal_src/test/test-three-reg-sub.gc        |   5 +
 goalc/CMakeLists.txt                       |   1 +
 goalc/compiler/Compiler.h                  |   9 +
 goalc/compiler/Env.cpp                     |  17 +-
 goalc/compiler/Env.h                       |  29 ++-
 goalc/compiler/IR.cpp                      | 176 +++++++++++++++-
 goalc/compiler/IR.h                        |  29 +++
 goalc/compiler/Util.cpp                    |   4 +
 goalc/compiler/Val.cpp                     |  16 +-
 goalc/compiler/compilation/Atoms.cpp       |  34 ++--
 goalc/compiler/compilation/ControlFlow.cpp | 225 +++++++++++++++++++++
 goalc/compiler/compilation/Define.cpp      |  39 ++++
 goalc/compiler/compilation/Macro.cpp       |  18 ++
 goalc/compiler/compilation/Math.cpp        |  27 ++-
 goalc/main.cpp                             |   2 +-
 test/test_compiler_and_runtime.cpp         |  14 ++
 32 files changed, 843 insertions(+), 44 deletions(-)
 create mode 100644 goal_src/test/test-defsmacro-defgmacro.gc
 create mode 100644 goal_src/test/test-desfun.gc
 create mode 100644 goal_src/test/test-div-1.gc
 create mode 100644 goal_src/test/test-div-2.gc
 create mode 100644 goal_src/test/test-factorial-loop.gc
 create mode 100644 goal_src/test/test-factorial-recursive.gc
 create mode 100644 goal_src/test/test-mlet.gc
 create mode 100644 goal_src/test/test-protect.gc
 create mode 100644 goal_src/test/test-set-symbol.gc
 create mode 100644 goal_src/test/test-three-reg-add.gc
 create mode 100644 goal_src/test/test-three-reg-mult.gc
 create mode 100644 goal_src/test/test-three-reg-sub.gc
 create mode 100644 goalc/compiler/compilation/ControlFlow.cpp

diff --git a/game/overlord/iso.cpp b/game/overlord/iso.cpp
index b374e3388..17424022b 100644
--- a/game/overlord/iso.cpp
+++ b/game/overlord/iso.cpp
@@ -597,8 +597,9 @@ u32 RunDGOStateMachine(IsoMessage* _cmd, IsoBufferHeader* buffer) {
 
         // once we're done, send the header to the EE, and start reading object data
         if (cmd->bytes_processed == sizeof(ObjectHeader)) {
-          printf("[Overlord DGO] Got object header for %s, object size 0x%x bytes (sent to 0x%p)\n",
-                 cmd->objHeader.name, cmd->objHeader.size, cmd->ee_destination_buffer);
+          //          printf("[Overlord DGO] Got object header for %s, object size 0x%x bytes (sent
+          //          to 0x%p)\n",
+          //                 cmd->objHeader.name, cmd->objHeader.size, cmd->ee_destination_buffer);
           DMA_SendToEE(&cmd->objHeader, sizeof(ObjectHeader), cmd->ee_destination_buffer);
           DMA_Sync();
           cmd->ee_destination_buffer += sizeof(ObjectHeader);
diff --git a/goal_src/goal-lib.gc b/goal_src/goal-lib.gc
index 77ae4e31f..aaf565df3 100644
--- a/goal_src/goal-lib.gc
+++ b/goal_src/goal-lib.gc
@@ -33,6 +33,14 @@
      )
   )
 
+(defmacro blg ()
+  `(begin
+     (build-game)
+     (dgo-load "kernel" global #xf #x200000)
+     (dgo-load "game" global #xf #x200000)
+     )
+  )
+
 (defmacro e ()
   `(:exit)
   )
@@ -109,4 +117,54 @@
     ;; otherwise don't ignore it.
     `(define ,name (lambda :name ,name ,bindings ,@body))
     )
+  )
+
+(defmacro while (test &rest body)
+  (with-gensyms (reloop test-exit)
+    `(begin
+       (goto ,test-exit)
+       (label ,reloop)
+       ,@body
+       (label ,test-exit)
+       (when-goto ,test ,reloop)
+       #f
+       )
+    )
+  )
+
+;; Backup some values, and restore after executing body.
+;; Non-dynamic (nonlocal jumps out of body will skip restore)
+(defmacro protect (defs &rest body)
+  (if (null? defs)
+    ;; nothing to backup, just insert body (base case)
+    `(begin ,@body)
+
+    ;; a unique name for the thing we are backing up
+    (with-gensyms (backup)
+                  ;; store the original value of the first def in backup
+                  `(let ((,backup ,(first defs)))
+                     ;; backup any other things which need backing up
+                     (protect ,(cdr defs)
+                              ;; execute the body
+                              ,@body
+                              )
+                     ;; restore the first thing
+                     (set! ,(first defs) ,backup)
+                     )
+                  )
+    )
+  )
+
+(defmacro +! (place amount)
+  `(set! ,place (+ ,place ,amount))
+  )
+
+;; todo, handle too many arguments correct
+(defmacro if (condition true-case &rest others)
+  (if (null? others)
+    `(cond (,condition ,true-case))
+    `(cond (,condition ,true-case)
+           (else ,(first others))
+           )
+    )
   )
\ No newline at end of file
diff --git a/goal_src/kernel-defs.gc b/goal_src/kernel-defs.gc
index 3c97a5608..862d2c7ff 100644
--- a/goal_src/kernel-defs.gc
+++ b/goal_src/kernel-defs.gc
@@ -77,7 +77,7 @@
 (define-extern new-dynamic-structure (function kheap type int structure))
 (define-extern method-set! (function type int function none)) ;; may actually return function.
 (define-extern link (function pointer string int kheap int pointer))
-(define-extern dgo-load (function string kheap int int))
+(define-extern dgo-load (function string kheap int int none))
 (define-extern link-begin (function pointer string int kheap int int))
 (define-extern link-resume (function int))
 ;; mc-run
diff --git a/goal_src/kernel/gcommon.gc b/goal_src/kernel/gcommon.gc
index 057dfb5d3..74b27d1fe 100644
--- a/goal_src/kernel/gcommon.gc
+++ b/goal_src/kernel/gcommon.gc
@@ -18,7 +18,77 @@
   ;; there is an optional "docstring" that can go at the beginning of a function
   "Function which returns its input. The first function of the game!"
   
-  ;; the last thing in the function body is the return value.
+  ;; the last thing in the function body is the return value. This is like "return x;" in C
+  ;; the return type of the function is figured out automatically by the compiler
+  ;; you don't have to specify it manually.
   x
   )
 
+
+(defun 1/ ((x float))
+  "Reciprocal floating point"
+  
+  ;; this function computes 1.0 / x.  GOAL allows strange function names like "1/".
+  
+  ;; Declaring this an inline function is like a C inline function, however code is
+  ;; still generated so it can be used a function object. GOAL inline functions have type
+  ;; checking, so they are preferable to macros when possible, to get better error messages.
+  (declare (inline))
+  
+  ;; the division form will pick the math type (float, int) based on the type of the first
+  ;; argument.  In this case, "1." is a floating point constant, so this becomes a floating point division.
+  (/ 1. x)
+  )
+
+(defun + ((x int) (y int))
+  "Compute the sum of two integers"
+  
+  ;; this wraps the compiler's built-in handling of "add two integers" in a GOAL function.
+  ;; now "+" can be used as a function object, but is limited to adding two integers when used like this.
+  ;; The compiler is smart enough to not use this function unless "+" is being used as a function object.
+  ;; ex: (+ a b c), (+ a b) ; won't use this function, uses built-in addition
+  ;; (set-combination-function! my-thing +) ; + becomes a function pointer in this case
+  (+ x y)
+  )
+
+(defun - ((x int) (y int))
+  "Compute the difference of two integers"
+  (- x y)
+  )
+
+(defun * ((x int) (y int))
+  "Compute the product of two integers"
+  ;; TODO - verify that this matches the PS2 exactly.
+  ;; Uses mult (three operand form) in MIPS
+  (* x y)
+  )
+
+(defun / ((x int) (y int))
+  "Compute the quotient of two integers"
+  ;; TODO - verify this matches the PS2 exactly
+  (/ x y)
+  )
+
+;; todo ash
+;; todo mod
+;; todo rem
+
+(defun abs ((a int))
+  "Take the absolute value of an integer"
+  
+  ;; short function, good candidate for inlining
+  (declare (inline))
+  
+  ;; The original implementation was inline assembly, to take advantage of branch delay slots:
+  ;;  (or v0 a0 r0)     ;; move input to output unchanged, for positive case
+  ;;  (bltzl v0 end)    ;; if negative, execute the branch delay slot below...
+  ;;  (dsubu v0 r0 v0)  ;; negate
+  ;;  (label end)
+ 
+  
+  (if (> a 0) ;; condition is "a > 0"
+      a       ;; true case, return a
+      (- a)   ;; false case, return -a. (- a) is like (- 0 a)
+      )
+  )
+
diff --git a/goal_src/test/test-build-game.gc b/goal_src/test/test-build-game.gc
index 83f28a46f..fe473f2e1 100644
--- a/goal_src/test/test-build-game.gc
+++ b/goal_src/test/test-build-game.gc
@@ -1,6 +1,4 @@
 (build-game)
-;(define-extern global kheap)
-;(define-extern dgo-load (function string kheap int int int))
-;(dgo-load "kernel" global #xf #x200000) ; todo, remove once kernel loads itself.
-;(dgo-load "game" global #xf #x200000)
+(dgo-load "kernel" global #xf #x200000) ; todo, remove once kernel loads itself.
+(dgo-load "game" global #xf #x200000)
 1
\ No newline at end of file
diff --git a/goal_src/test/test-defsmacro-defgmacro.gc b/goal_src/test/test-defsmacro-defgmacro.gc
new file mode 100644
index 000000000..8917115af
--- /dev/null
+++ b/goal_src/test/test-defsmacro-defgmacro.gc
@@ -0,0 +1,13 @@
+(defsmacro test-macro (x)
+  ;; goos macro
+  `(+ ,x 2)
+  )
+
+(defmacro test-macro (x)
+  ;; goal macro which calls a goos macro of the same name
+  (let ((goos-expansion (test-macro x)))
+    `(+ ,goos-expansion 3)
+    )
+  )
+
+(test-macro 15)
\ No newline at end of file
diff --git a/goal_src/test/test-desfun.gc b/goal_src/test/test-desfun.gc
new file mode 100644
index 000000000..5e8f8f100
--- /dev/null
+++ b/goal_src/test/test-desfun.gc
@@ -0,0 +1,10 @@
+(desfun square (x)
+	(* x x)
+	)
+
+
+(defmacro call-square (x)
+  (square x)
+  )
+
+(call-square 2)
\ No newline at end of file
diff --git a/goal_src/test/test-div-1.gc b/goal_src/test/test-div-1.gc
new file mode 100644
index 000000000..d8b1fc6cb
--- /dev/null
+++ b/goal_src/test/test-div-1.gc
@@ -0,0 +1 @@
+(+ 1 2 (/ (* 2 5) (+ 1 2)))
\ No newline at end of file
diff --git a/goal_src/test/test-div-2.gc b/goal_src/test/test-div-2.gc
new file mode 100644
index 000000000..bb6606249
--- /dev/null
+++ b/goal_src/test/test-div-2.gc
@@ -0,0 +1,3 @@
+(let ((x 30))
+  (+ (/ x 10) 4)
+  )
\ No newline at end of file
diff --git a/goal_src/test/test-factorial-loop.gc b/goal_src/test/test-factorial-loop.gc
new file mode 100644
index 000000000..5eac59b43
--- /dev/null
+++ b/goal_src/test/test-factorial-loop.gc
@@ -0,0 +1,11 @@
+(defun factorial-iterative ((x integer))
+  (let ((result 1))
+    (while (!= x 1)
+	   (set! result (* result x))
+	   (set! x (- x 1))
+	   )
+    result
+    )
+  )
+
+(factorial-iterative 10)
\ No newline at end of file
diff --git a/goal_src/test/test-factorial-recursive.gc b/goal_src/test/test-factorial-recursive.gc
new file mode 100644
index 000000000..390981766
--- /dev/null
+++ b/goal_src/test/test-factorial-recursive.gc
@@ -0,0 +1,12 @@
+;; for now, recursive functions need to forward declare so they have their
+;; return type.
+;(defun-extern factorial-recursive ((x integer)) integer)
+(define-extern factorial-recursive (function integer integer))
+
+(defun factorial-recursive ((x integer))
+  (cond ((= x 1) x)
+	(else (* x (factorial-recursive (- x 1))))
+	)
+  )
+
+(factorial-recursive 10)
\ No newline at end of file
diff --git a/goal_src/test/test-mlet.gc b/goal_src/test/test-mlet.gc
new file mode 100644
index 000000000..0b034d8cd
--- /dev/null
+++ b/goal_src/test/test-mlet.gc
@@ -0,0 +1,7 @@
+(defglobalconstant c1 3)
+
+(+ c1 (mlet ((c1 4))
+	    c1
+	    )
+   c1
+   )
diff --git a/goal_src/test/test-protect.gc b/goal_src/test/test-protect.gc
new file mode 100644
index 000000000..7c7025e24
--- /dev/null
+++ b/goal_src/test/test-protect.gc
@@ -0,0 +1,15 @@
+(let ((var1 10)
+      (var2 20)
+      (sum 0)
+      )
+
+  (protect (var1 var2)
+           (set! var1 1)
+           (set! var2 2)
+           (+! sum var1)
+           (+! sum var2)
+           )
+  (+! sum var1)
+  (+! sum var2)
+  sum
+  )
diff --git a/goal_src/test/test-set-symbol.gc b/goal_src/test/test-set-symbol.gc
new file mode 100644
index 000000000..910d3eef6
--- /dev/null
+++ b/goal_src/test/test-set-symbol.gc
@@ -0,0 +1,18 @@
+
+(defun burp ((thing integer))
+  (* thing 3)
+  )
+
+(define thing 2)
+
+(set! thing 3)
+
+
+(+ (let ((thing 4))
+     (set! thing (+ thing 1))
+     thing
+     )
+  (burp thing)
+  (set! thing 4)
+  thing
+  )
diff --git a/goal_src/test/test-three-reg-add.gc b/goal_src/test/test-three-reg-add.gc
new file mode 100644
index 000000000..16d3aa526
--- /dev/null
+++ b/goal_src/test/test-three-reg-add.gc
@@ -0,0 +1,3 @@
+(let ((x 3))
+  (+ (+ x 1) x)
+  )
\ No newline at end of file
diff --git a/goal_src/test/test-three-reg-mult.gc b/goal_src/test/test-three-reg-mult.gc
new file mode 100644
index 000000000..5dc9a1ce4
--- /dev/null
+++ b/goal_src/test/test-three-reg-mult.gc
@@ -0,0 +1,6 @@
+
+(let ((x 3))
+  (* x 4)
+  (* x)
+  x
+  )
diff --git a/goal_src/test/test-three-reg-sub.gc b/goal_src/test/test-three-reg-sub.gc
new file mode 100644
index 000000000..994d0619c
--- /dev/null
+++ b/goal_src/test/test-three-reg-sub.gc
@@ -0,0 +1,5 @@
+(let ((x 3))
+  (- x 1)
+  (- x)
+  x
+  )
diff --git a/goalc/CMakeLists.txt b/goalc/CMakeLists.txt
index 0c9ba1f0f..3c309bec0 100644
--- a/goalc/CMakeLists.txt
+++ b/goalc/CMakeLists.txt
@@ -21,6 +21,7 @@ add_library(compiler
         compiler/compilation/Math.cpp
         compiler/compilation/Define.cpp
         compiler/compilation/Function.cpp
+        compiler/compilation/ControlFlow.cpp
         compiler/Util.cpp
         logger/Logger.cpp
         regalloc/IRegister.cpp
diff --git a/goalc/compiler/Compiler.h b/goalc/compiler/Compiler.h
index 2dbfb5386..2241a52e3 100644
--- a/goalc/compiler/Compiler.h
+++ b/goalc/compiler/Compiler.h
@@ -99,6 +99,7 @@ class Compiler {
   Val* number_to_float(Val* in, Env* env);
   Val* number_to_binteger(Val* in, Env* env);
   Val* to_math_type(Val* in, MathMode mode, Env* env);
+  bool is_none(Val* in);
 
  public:
   // Atoms
@@ -123,14 +124,22 @@ class Compiler {
   Val* compile_in_package(const goos::Object& form, const goos::Object& rest, Env* env);
   Val* compile_build_dgo(const goos::Object& form, const goos::Object& rest, Env* env);
 
+  // ControlFlow
+  Condition compile_condition(const goos::Object& condition, Env* env, bool invert);
+  Val* compile_condition_as_bool(const goos::Object& form, const goos::Object& rest, Env* env);
+  Val* compile_when_goto(const goos::Object& form, const goos::Object& rest, Env* env);
+  Val* compile_cond(const goos::Object& form, const goos::Object& rest, Env* env);
+
   // Define
   Val* compile_define(const goos::Object& form, const goos::Object& rest, Env* env);
   Val* compile_define_extern(const goos::Object& form, const goos::Object& rest, Env* env);
+  Val* compile_set(const goos::Object& form, const goos::Object& rest, Env* env);
 
   // Macro
   Val* compile_gscond(const goos::Object& form, const goos::Object& rest, Env* env);
   Val* compile_quote(const goos::Object& form, const goos::Object& rest, Env* env);
   Val* compile_defglobalconstant(const goos::Object& form, const goos::Object& rest, Env* env);
+  Val* compile_mlet(const goos::Object& form, const goos::Object& rest, Env* env);
 
   // Math
   Val* compile_add(const goos::Object& form, const goos::Object& rest, Env* env);
diff --git a/goalc/compiler/Env.cpp b/goalc/compiler/Env.cpp
index 07ebf17c3..1e2b5ebd0 100644
--- a/goalc/compiler/Env.cpp
+++ b/goalc/compiler/Env.cpp
@@ -31,7 +31,7 @@ void Env::constrain_reg(IRegConstraint constraint) {
 /*!
  * Lookup the given symbol object as a lexical variable.
  */
-Val* Env::lexical_lookup(goos::Object sym) {
+RegVal* Env::lexical_lookup(goos::Object sym) {
   return m_parent->lexical_lookup(std::move(sym));
 }
 
@@ -93,7 +93,7 @@ void GlobalEnv::constrain_reg(IRegConstraint constraint) {
 /*!
  * Lookup the given symbol object as a lexical variable.
  */
-Val* GlobalEnv::lexical_lookup(goos::Object sym) {
+RegVal* GlobalEnv::lexical_lookup(goos::Object sym) {
   (void)sym;
   return nullptr;
 }
@@ -218,6 +218,15 @@ void FunctionEnv::resolve_gotos() {
     }
     gt.ir->resolve(&kv_label->second);
   }
+
+  for (auto& gt : unresolved_cond_gotos) {
+    auto kv_label = m_labels.find(gt.label);
+    if (kv_label == m_labels.end()) {
+      throw std::runtime_error("invalid when-goto destination " + gt.label);
+    }
+    gt.ir->label = kv_label->second;
+    gt.ir->mark_as_resolved();
+  }
 }
 
 RegVal* FunctionEnv::make_ireg(TypeSpec ts, emitter::RegKind kind) {
@@ -238,7 +247,7 @@ std::unordered_map<std::string, Label>& LabelEnv::get_label_map() {
   return m_labels;
 }
 
-Val* FunctionEnv::lexical_lookup(goos::Object sym) {
+RegVal* FunctionEnv::lexical_lookup(goos::Object sym) {
   if (!sym.is_symbol()) {
     throw std::runtime_error("invalid symbol in lexical_lookup");
   }
@@ -259,7 +268,7 @@ std::string LexicalEnv::print() {
   return "lexical";
 }
 
-Val* LexicalEnv::lexical_lookup(goos::Object sym) {
+RegVal* LexicalEnv::lexical_lookup(goos::Object sym) {
   if (!sym.is_symbol()) {
     throw std::runtime_error("invalid symbol in lexical_lookup");
   }
diff --git a/goalc/compiler/Env.h b/goalc/compiler/Env.h
index a9fc91c03..7f522bb3a 100644
--- a/goalc/compiler/Env.h
+++ b/goalc/compiler/Env.h
@@ -31,7 +31,7 @@ class Env {
   virtual void emit(std::unique_ptr<IR> ir);
   virtual RegVal* make_ireg(TypeSpec ts, emitter::RegKind kind);
   virtual void constrain_reg(IRegConstraint constraint);  // todo, remove!
-  virtual Val* lexical_lookup(goos::Object sym);
+  virtual RegVal* lexical_lookup(goos::Object sym);
   virtual BlockEnv* find_block(const std::string& name);
   virtual std::unordered_map<std::string, Label>& get_label_map();
   RegVal* make_gpr(TypeSpec ts);
@@ -54,7 +54,7 @@ class GlobalEnv : public Env {
   void emit(std::unique_ptr<IR> ir) override;
   RegVal* make_ireg(TypeSpec ts, emitter::RegKind kind) override;
   void constrain_reg(IRegConstraint constraint) override;
-  Val* lexical_lookup(goos::Object sym) override;
+  RegVal* lexical_lookup(goos::Object sym) override;
   BlockEnv* find_block(const std::string& name) override;
   ~GlobalEnv() = default;
 
@@ -128,7 +128,14 @@ class DeclareEnv : public Env {
 class IR_GotoLabel;
 
 struct UnresolvedGoto {
-  IR_GotoLabel* ir;
+  IR_GotoLabel* ir = nullptr;
+  std::string label;
+};
+
+class IR_ConditionalBranch;
+
+struct UnresolvedConditionalGoto {
+  IR_ConditionalBranch* ir = nullptr;
   std::string label;
 };
 
@@ -146,13 +153,18 @@ class FunctionEnv : public DeclareEnv {
   const std::vector<IRegConstraint>& constraints() { return m_constraints; }
   void constrain(const IRegConstraint& c) { m_constraints.push_back(c); }
   void set_allocations(const AllocationResult& result) { m_regalloc_result = result; }
-  Val* lexical_lookup(goos::Object sym) override;
+  RegVal* lexical_lookup(goos::Object sym) override;
 
   const AllocationResult& alloc_result() { return m_regalloc_result; }
 
   bool needs_aligned_stack() const { return m_aligned_stack_required; }
   void require_aligned_stack() { m_aligned_stack_required = true; }
 
+  Label* alloc_unnamed_label() {
+    m_unnamed_labels.emplace_back(std::make_unique<Label>());
+    return m_unnamed_labels.back().get();
+  }
+
   int idx_in_file = -1;
 
   template <typename T, class... Args>
@@ -173,7 +185,8 @@ class FunctionEnv : public DeclareEnv {
   std::string method_of_type_name = "#f";
   bool is_asm_func = false;
   std::vector<UnresolvedGoto> unresolved_gotos;
-  std::unordered_map<std::string, Val*> params;
+  std::vector<UnresolvedConditionalGoto> unresolved_cond_gotos;
+  std::unordered_map<std::string, RegVal*> params;
 
  protected:
   void resolve_gotos();
@@ -189,6 +202,7 @@ class FunctionEnv : public DeclareEnv {
   bool m_aligned_stack_required = false;
 
   std::unordered_map<std::string, Label> m_labels;
+  std::vector<std::unique_ptr<Label>> m_unnamed_labels;
 };
 
 class BlockEnv : public Env {
@@ -206,9 +220,9 @@ class BlockEnv : public Env {
 class LexicalEnv : public DeclareEnv {
  public:
   explicit LexicalEnv(Env* parent) : DeclareEnv(parent) {}
-  Val* lexical_lookup(goos::Object sym) override;
+  RegVal* lexical_lookup(goos::Object sym) override;
   std::string print() override;
-  std::unordered_map<std::string, Val*> vars;
+  std::unordered_map<std::string, RegVal*> vars;
 };
 
 class LabelEnv : public Env {
@@ -232,6 +246,7 @@ class SymbolMacroEnv : public Env {
  public:
   explicit SymbolMacroEnv(Env* parent) : Env(parent) {}
   std::unordered_map<std::shared_ptr<goos::SymbolObject>, goos::Object> macros;
+  std::string print() override { return "symbol-macro-env"; }
 };
 
 template <typename T>
diff --git a/goalc/compiler/IR.cpp b/goalc/compiler/IR.cpp
index 3174425e2..e30b2d039 100644
--- a/goalc/compiler/IR.cpp
+++ b/goalc/compiler/IR.cpp
@@ -77,7 +77,26 @@ void IR_LoadConstant64::do_codegen(emitter::ObjectGenerator* gen,
                                    const AllocationResult& allocs,
                                    emitter::IR_Record irec) {
   auto dest_reg = get_reg(m_dest, allocs, irec);
-  gen->add_instr(IGen::mov_gpr64_u64(dest_reg, m_value), irec);
+
+  s64 svalue = m_value;
+
+  if (svalue == 0) {
+    gen->add_instr(IGen::xor_gpr64_gpr64(dest_reg, dest_reg), irec);
+  } else if (svalue > 0) {
+    if (svalue < UINT32_MAX) {
+      gen->add_instr(IGen::mov_gpr64_u32(dest_reg, m_value), irec);
+    } else {
+      // need a real 64 bit load
+      gen->add_instr(IGen::mov_gpr64_u64(dest_reg, m_value), irec);
+    }
+  } else {
+    if (svalue >= INT32_MIN) {
+      gen->add_instr(IGen::mov_gpr64_s32(dest_reg, svalue), irec);
+    } else {
+      // need a real 64 bit load
+      gen->add_instr(IGen::mov_gpr64_u64(dest_reg, m_value), irec);
+    }
+  }
 }
 
 /////////////////////
@@ -198,6 +217,8 @@ void IR_RegSet::do_codegen(emitter::ObjectGenerator* gen,
     gen->add_instr(IGen::mov_gpr64_gpr64(dest_reg, val_reg), irec);
   } else if (val_reg.is_xmm() && dest_reg.is_gpr()) {
     gen->add_instr(IGen::movd_gpr32_xmm32(dest_reg, val_reg), irec);
+  } else if (val_reg.is_gpr() && dest_reg.is_xmm()) {
+    gen->add_instr(IGen::movd_xmm32_gpr32(dest_reg, val_reg), irec);
   } else {
     assert(false);
   }
@@ -371,6 +392,8 @@ std::string IR_IntegerMath::print() {
       return fmt::format("subi {}, {}", m_dest->print(), m_arg->print());
     case IntegerMathKind::IMUL_32:
       return fmt::format("imul {}, {}", m_dest->print(), m_arg->print());
+    case IntegerMathKind::IDIV_32:
+      return fmt::format("idiv {}, {}", m_dest->print(), m_arg->print());
     default:
       assert(false);
   }
@@ -381,6 +404,10 @@ RegAllocInstr IR_IntegerMath::to_rai() {
   rai.write.push_back(m_dest->ireg());
   rai.read.push_back(m_dest->ireg());
   rai.read.push_back(m_arg->ireg());
+
+  if (m_kind == IntegerMathKind::IDIV_32) {
+    rai.exclude.emplace_back(emitter::RDX);
+  }
   return rai;
 }
 
@@ -400,9 +427,50 @@ void IR_IntegerMath::do_codegen(emitter::ObjectGenerator* gen,
       auto dr = get_reg(m_dest, allocs, irec);
       gen->add_instr(IGen::imul_gpr32_gpr32(dr, get_reg(m_arg, allocs, irec)), irec);
       gen->add_instr(IGen::movsx_r64_r32(dr, dr), irec);
-    }
+    } break;
 
-    break;
+    case IntegerMathKind::IDIV_32: {
+      gen->add_instr(IGen::cdq(), irec);
+      gen->add_instr(IGen::idiv_gpr32(get_reg(m_arg, allocs, irec)), irec);
+      gen->add_instr(IGen::movsx_r64_r32(get_reg(m_dest, allocs, irec), emitter::RAX), irec);
+    } break;
+    default:
+      assert(false);
+  }
+}
+
+/////////////////////
+// FloatMath
+/////////////////////
+
+IR_FloatMath::IR_FloatMath(FloatMathKind kind, RegVal* dest, RegVal* arg)
+    : m_kind(kind), m_dest(dest), m_arg(arg) {}
+
+std::string IR_FloatMath::print() {
+  switch (m_kind) {
+    case FloatMathKind::DIV_SS:
+      return fmt::format("divss {}, {}", m_dest->print(), m_arg->print());
+    default:
+      assert(false);
+  }
+}
+
+RegAllocInstr IR_FloatMath::to_rai() {
+  RegAllocInstr rai;
+  rai.write.push_back(m_dest->ireg());
+  rai.read.push_back(m_dest->ireg());
+  rai.read.push_back(m_arg->ireg());
+  return rai;
+}
+
+void IR_FloatMath::do_codegen(emitter::ObjectGenerator* gen,
+                              const AllocationResult& allocs,
+                              emitter::IR_Record irec) {
+  switch (m_kind) {
+    case FloatMathKind::DIV_SS:
+      gen->add_instr(
+          IGen::divss_xmm_xmm(get_reg(m_dest, allocs, irec), get_reg(m_arg, allocs, irec)), irec);
+      break;
     default:
       assert(false);
   }
@@ -441,4 +509,106 @@ void IR_StaticVarLoad::do_codegen(emitter::ObjectGenerator* gen,
   } else {
     assert(false);
   }
+}
+
+/////////////////////
+// ConditionalBranch
+/////////////////////
+
+std::string Condition::print() const {
+  switch (kind) {
+    case ConditionKind::NOT_EQUAL:
+      return a->print() + " != " + b->print();
+    case ConditionKind::EQUAL:
+      return a->print() + " == " + b->print();
+    case ConditionKind::LEQ:
+      return a->print() + " <= " + b->print();
+    case ConditionKind::GEQ:
+      return a->print() + " >= " + b->print();
+    case ConditionKind::LT:
+      return a->print() + " < " + b->print();
+    case ConditionKind::GT:
+      return a->print() + " > " + b->print();
+    default:
+      throw std::runtime_error("unknown condition type in GoalCondition::print()");
+  }
+}
+
+RegAllocInstr Condition::to_rai() {
+  RegAllocInstr rai;
+  rai.read.push_back(a->ireg());
+  rai.read.push_back(b->ireg());
+  return rai;
+}
+
+IR_ConditionalBranch::IR_ConditionalBranch(const Condition& _condition, Label _label)
+    : condition(_condition), label(_label) {}
+
+std::string IR_ConditionalBranch::print() {
+  // todo, float/signed info?
+  return fmt::format("j({}) {}", condition.print(), label.print());
+}
+
+RegAllocInstr IR_ConditionalBranch::to_rai() {
+  auto rai = condition.to_rai();
+  assert(m_resolved);
+  rai.jumps.push_back(label.idx);
+  return rai;
+}
+
+void IR_ConditionalBranch::do_codegen(emitter::ObjectGenerator* gen,
+                                      const AllocationResult& allocs,
+                                      emitter::IR_Record irec) {
+  Instruction jump_instr(0);
+  assert(m_resolved);
+  switch (condition.kind) {
+    case ConditionKind::EQUAL:
+      jump_instr = IGen::je_32();
+      break;
+    case ConditionKind::NOT_EQUAL:
+      jump_instr = IGen::jne_32();
+      break;
+    case ConditionKind::LEQ:
+      if (condition.is_signed) {
+        jump_instr = IGen::jle_32();
+      } else {
+        jump_instr = IGen::jbe_32();
+      }
+      break;
+    case ConditionKind::GEQ:
+      if (condition.is_signed) {
+        jump_instr = IGen::jge_32();
+      } else {
+        jump_instr = IGen::jae_32();
+      }
+      break;
+
+    case ConditionKind::LT:
+      if (condition.is_signed) {
+        jump_instr = IGen::jl_32();
+      } else {
+        jump_instr = IGen::jb_32();
+      }
+      break;
+    case ConditionKind::GT:
+      if (condition.is_signed) {
+        jump_instr = IGen::jg_32();
+      } else {
+        jump_instr = IGen::ja_32();
+      }
+      break;
+    default:
+      assert(false);
+  }
+
+  if (condition.is_float) {
+    assert(false);  // for now
+  } else {
+    gen->add_instr(IGen::cmp_gpr64_gpr64(get_reg(condition.a, allocs, irec),
+                                         get_reg(condition.b, allocs, irec)),
+                   irec);
+  }
+
+  auto jump_rec = gen->add_instr(jump_instr, irec);
+  gen->link_instruction_jump(jump_rec, gen->get_future_ir_record_in_same_func(irec, label.idx));
 }
\ No newline at end of file
diff --git a/goalc/compiler/IR.h b/goalc/compiler/IR.h
index cd9a59ae6..874289b15 100644
--- a/goalc/compiler/IR.h
+++ b/goalc/compiler/IR.h
@@ -239,4 +239,33 @@ class IR_FloatMath : public IR {
   RegVal* m_arg;
 };
 
+enum class ConditionKind { NOT_EQUAL, EQUAL, LEQ, LT, GT, GEQ, INVALID_CONDITION };
+
+struct Condition {
+  ConditionKind kind = ConditionKind::INVALID_CONDITION;
+  RegVal* a = nullptr;
+  RegVal* b = nullptr;
+  bool is_signed = false;
+  bool is_float = false;
+  RegAllocInstr to_rai();
+  std::string print() const;
+};
+
+class IR_ConditionalBranch : public IR {
+ public:
+  IR_ConditionalBranch(const Condition& condition, Label _label);
+  std::string print() override;
+  RegAllocInstr to_rai() override;
+  void do_codegen(emitter::ObjectGenerator* gen,
+                  const AllocationResult& allocs,
+                  emitter::IR_Record irec) override;
+  void mark_as_resolved() { m_resolved = true; }
+
+  Condition condition;
+  Label label;
+
+ private:
+  bool m_resolved = false;
+};
+
 #endif  // JAK_IR_H
diff --git a/goalc/compiler/Util.cpp b/goalc/compiler/Util.cpp
index a4800126f..105e6c28a 100644
--- a/goalc/compiler/Util.cpp
+++ b/goalc/compiler/Util.cpp
@@ -167,4 +167,8 @@ emitter::RegKind Compiler::get_preferred_reg_kind(const TypeSpec& ts) {
     default:
       assert(false);
   }
+}
+
+bool Compiler::is_none(Val* in) {
+  return dynamic_cast<None*>(in);
 }
\ No newline at end of file
diff --git a/goalc/compiler/Val.cpp b/goalc/compiler/Val.cpp
index 889cf1cc2..e280f64f4 100644
--- a/goalc/compiler/Val.cpp
+++ b/goalc/compiler/Val.cpp
@@ -21,8 +21,12 @@ RegVal* Val::to_gpr(Env* fe) {
  * Fallback to_xmm if a more optimized one is not provided.
  */
 RegVal* Val::to_xmm(Env* fe) {
-  (void)fe;
-  throw std::runtime_error("Val::to_xmm NYI");  // todo
+  auto rv = to_reg(fe);
+  if (rv->ireg().kind == emitter::RegKind::XMM) {
+    return rv;
+  } else {
+    assert(false);
+  }
 }
 
 RegVal* RegVal::to_reg(Env* fe) {
@@ -35,7 +39,9 @@ RegVal* RegVal::to_gpr(Env* fe) {
   if (m_ireg.kind == emitter::RegKind::GPR) {
     return this;
   } else {
-    throw std::runtime_error("RegVal::to_gpr NYI");  // todo
+    auto re = fe->make_gpr(m_ts);
+    fe->emit(std::make_unique<IR_RegSet>(re, this));
+    return re;
   }
 }
 
@@ -44,7 +50,9 @@ RegVal* RegVal::to_xmm(Env* fe) {
   if (m_ireg.kind == emitter::RegKind::XMM) {
     return this;
   } else {
-    throw std::runtime_error("RegVal::to_xmm NYI");  // todo
+    auto re = fe->make_xmm(m_ts);
+    fe->emit(std::make_unique<IR_RegSet>(re, this));
+    return re;
   }
 }
 
diff --git a/goalc/compiler/compilation/Atoms.cpp b/goalc/compiler/compilation/Atoms.cpp
index e66d14065..a703c4f09 100644
--- a/goalc/compiler/compilation/Atoms.cpp
+++ b/goalc/compiler/compilation/Atoms.cpp
@@ -45,13 +45,13 @@ static const std::unordered_map<
         {"seval", &Compiler::compile_seval},
         //
         //        // CONTROL FLOW
-        //        {"cond", &Compiler::compile_cond},
-        //        {"when-goto", &Compiler::compile_when_goto},
+        {"cond", &Compiler::compile_cond},
+        {"when-goto", &Compiler::compile_when_goto},
         //
         //        // DEFINITION
         {"define", &Compiler::compile_define},
         {"define-extern", &Compiler::compile_define_extern},
-        //        {"set!", &Compiler::compile_set},
+        {"set!", &Compiler::compile_set},
         //        {"defun-extern", &Compiler::compile_defun_extern},
         //        {"declare-method", &Compiler::compile_declare_method},
         //
@@ -72,7 +72,7 @@ static const std::unordered_map<
         {"inline", &Compiler::compile_inline},
         //        {"with-inline", &Compiler::compile_with_inline},
         //        {"rlet", &Compiler::compile_rlet},
-        //        {"mlet", &Compiler::compile_mlet},
+
         //        {"get-ra-ptr", &Compiler::compile_get_ra_ptr},
         //
         //
@@ -80,6 +80,7 @@ static const std::unordered_map<
         //        // MACRO
         //        {"print-type", &Compiler::compile_print_type},
         {"quote", &Compiler::compile_quote},
+        {"mlet", &Compiler::compile_mlet},
         //        {"defconstant", &Compiler::compile_defconstant},
         //
         //        // OBJECT
@@ -113,14 +114,14 @@ static const std::unordered_map<
         //        {"logxor", &Compiler::compile_logxor},
         //        {"logand", &Compiler::compile_logand},
         //        {"lognot", &Compiler::compile_lognot},
-        //        {"=", &Compiler::compile_condition_as_bool},
-        //        {"!=", &Compiler::compile_condition_as_bool},
-        //        {"eq?", &Compiler::compile_condition_as_bool},
-        //        {"not", &Compiler::compile_condition_as_bool},
-        //        {"<=", &Compiler::compile_condition_as_bool},
-        //        {">=", &Compiler::compile_condition_as_bool},
-        //        {"<", &Compiler::compile_condition_as_bool},
-        //        {">", &Compiler::compile_condition_as_bool},
+        {"=", &Compiler::compile_condition_as_bool},
+        {"!=", &Compiler::compile_condition_as_bool},
+        {"eq?", &Compiler::compile_condition_as_bool},
+        {"not", &Compiler::compile_condition_as_bool},
+        {"<=", &Compiler::compile_condition_as_bool},
+        {">=", &Compiler::compile_condition_as_bool},
+        {"<", &Compiler::compile_condition_as_bool},
+        {">", &Compiler::compile_condition_as_bool},
         //
         //        // BUILDER (build-dgo/build-cgo?)
         {"build-dgos", &Compiler::compile_build_dgo},
@@ -202,7 +203,14 @@ Val* Compiler::compile_symbol(const goos::Object& form, Env* env) {
     return get_none();
   }
 
-  // todo mlet
+  auto mlet_env = get_parent_env_of_type<SymbolMacroEnv>(env);
+  while (mlet_env) {
+    auto mlkv = mlet_env->macros.find(form.as_symbol());
+    if (mlkv != mlet_env->macros.end()) {
+      return compile_error_guard(mlkv->second, env);
+    }
+    mlet_env = get_parent_env_of_type<SymbolMacroEnv>(mlet_env->parent());
+  }
 
   auto lexical = env->lexical_lookup(form);
   if (lexical) {
diff --git a/goalc/compiler/compilation/ControlFlow.cpp b/goalc/compiler/compilation/ControlFlow.cpp
new file mode 100644
index 000000000..cdbdf9435
--- /dev/null
+++ b/goalc/compiler/compilation/ControlFlow.cpp
@@ -0,0 +1,225 @@
+#include "goalc/compiler/Compiler.h"
+
+/*!
+ * Convert a condition expression into a GoalCondition for use in a conditional branch.
+ * The reason for this design is to allow an optimization for
+ * (if (< a b) ...) to be compiled without actually computing a true/false value for the (< a b)
+ * expression. Instead, it will generate a cmp + jle sequence of instructions, which is much faster.
+ *
+ * This can be applied to _any_ GOAL form, and will return a GoalCondition which can be used with a
+ * Branch IR to branch if the condition is true/false.  When possible it applies the optimization
+ * mentioned above, but will be fine in other cases too.  I believe the original GOAL compiler had a
+ * similar system.
+ *
+ * Will branch if the condition is true and the invert flag is false.
+ * Will branch if the condition is false and the invert flag is true.
+ */
+Condition Compiler::compile_condition(const goos::Object& condition, Env* env, bool invert) {
+  Condition gc;
+
+  // These are special conditions that can be optimized into a cmp + jxx instruction.
+  const std::unordered_map<std::string, ConditionKind> conditions_inverted = {
+      {"!=", ConditionKind::EQUAL},   {"eq?", ConditionKind::NOT_EQUAL},
+      {"neq?", ConditionKind::EQUAL}, {"=", ConditionKind::NOT_EQUAL},
+      {">", ConditionKind::LEQ},      {"<", ConditionKind::GEQ},
+      {">=", ConditionKind::LT},      {"<=", ConditionKind::GT}};
+
+  const std::unordered_map<std::string, ConditionKind> conditions_normal = {
+      {"!=", ConditionKind::NOT_EQUAL},   {"eq?", ConditionKind::EQUAL},
+      {"neq?", ConditionKind::NOT_EQUAL}, {"=", ConditionKind::EQUAL},
+      {">", ConditionKind::GT},           {"<", ConditionKind::LT},
+      {">=", ConditionKind::GEQ},         {"<=", ConditionKind::LEQ}};
+
+  // possibly a form with an optimizable condition?
+  if (condition.is_pair()) {
+    auto first = pair_car(condition);
+    auto rest = pair_cdr(condition);
+
+    if (first.is_symbol()) {
+      auto fas = first.as_symbol();
+
+      // if there's a not, we can just try again to get an optimization with the invert flipped.
+      if (fas->name == "not") {
+        auto arg = pair_car(rest);
+        if (!pair_cdr(rest).is_empty_list()) {
+          throw_compile_error(condition, "A condition with \"not\" can have only one argument");
+        }
+        return compile_condition(arg, env, !invert);
+      }
+
+      auto& conditions = invert ? conditions_inverted : conditions_normal;
+      auto nc_kv = conditions.find(fas->name);
+
+      if (nc_kv != conditions.end()) {
+        // it is an optimizable condition!
+        gc.kind = nc_kv->second;
+
+        // get args...
+        auto args = get_va(rest, rest);
+        va_check(rest, args, {{}, {}}, {});
+        auto first_arg = compile_error_guard(args.unnamed.at(0), env);
+        auto second_arg = compile_error_guard(args.unnamed.at(1), env);
+
+        if (is_number(first_arg->type())) {
+          // it's a numeric comparison, so we may need to coerce.
+          auto math_mode = get_math_mode(first_arg->type());
+
+          // there is no support for comparing bintegers, so we turn the binteger comparison into an
+          // integer.
+          if (is_binteger(first_arg->type())) {
+            first_arg = number_to_integer(first_arg, env);
+          }
+
+          // convert second one to appropriate type as needed
+          if (is_number(second_arg->type())) {
+            second_arg = to_math_type(second_arg, math_mode, env);
+          }
+        }
+
+        // use signed comparison only if first argument is a signed integer (or coerced binteger)
+        // (floating point ignores this)
+        gc.is_signed = is_singed_integer_or_binteger(first_arg->type());
+
+        // pick between a floating point and an integer comparison.
+        if (is_float(first_arg->type())) {
+          gc.a = first_arg->to_xmm(env);
+          gc.b = second_arg->to_xmm(env);
+          gc.is_float = true;
+        } else {
+          gc.a = first_arg->to_gpr(env);
+          gc.b = second_arg->to_gpr(env);
+        }
+
+        return gc;
+      }
+    }
+  }
+
+  // not something we can process more.  Just check if we get false.
+  // todo - it's possible to optimize a false comparison because the false offset is zero
+  gc.kind = invert ? ConditionKind::EQUAL : ConditionKind::NOT_EQUAL;
+  gc.a = compile_error_guard(condition, env)->to_gpr(env);
+  gc.b = compile_get_sym_obj("#f", env)->to_gpr(env);
+
+  return gc;
+}
+
+Val* Compiler::compile_condition_as_bool(const goos::Object& form,
+                                         const goos::Object& rest,
+                                         Env* env) {
+  (void)rest;
+  auto c = compile_condition(form, env, true);
+  auto result = compile_get_sym_obj("#f", env)->to_gpr(env);  // todo - can be optimized.
+  Label label(get_parent_env_of_type<FunctionEnv>(env), -5);
+  auto branch_ir = std::make_unique<IR_ConditionalBranch>(c, label);
+  auto branch_ir_ref = branch_ir.get();
+  env->emit(std::move(branch_ir));
+
+  // move true
+  env->emit(std::make_unique<IR_RegSet>(
+      result, compile_get_sym_obj("#t", env)->to_gpr(env)));  // todo, can be optimized
+  branch_ir_ref->label.idx = branch_ir_ref->label.func->code().size();
+  branch_ir_ref->mark_as_resolved();
+
+  return result;
+}
+
+Val* Compiler::compile_when_goto(const goos::Object& form, const goos::Object& _rest, Env* env) {
+  (void)form;
+  auto* rest = &_rest;
+  auto condition_code = pair_car(*rest);
+  rest = &pair_cdr(*rest);
+
+  auto label = symbol_string(pair_car(*rest));
+  expect_empty_list(pair_cdr(*rest));
+
+  // compile as condition (will set flags register with a cmp instruction)
+  auto condition = compile_condition(condition_code, env, false);
+  auto branch = std::make_unique<IR_ConditionalBranch>(condition, Label());
+  get_parent_env_of_type<FunctionEnv>(env)->unresolved_cond_gotos.push_back({branch.get(), label});
+  env->emit(std::move(branch));
+  return get_none();
+}
+
+Val* Compiler::compile_cond(const goos::Object& form, const goos::Object& rest, Env* env) {
+  auto result = env->make_gpr(m_ts.make_typespec("object"));
+
+  auto fenv = get_parent_env_of_type<FunctionEnv>(env);
+  auto end_label = fenv->alloc_unnamed_label();
+  end_label->func = fenv;
+  end_label->idx = -3;  // placeholder
+
+  bool got_else = false;
+
+  std::vector<TypeSpec> case_result_types;
+
+  for_each_in_list(rest, [&](const goos::Object& o) {
+    auto test = pair_car(o);
+    auto clauses = pair_cdr(o);
+
+    if (got_else) {
+      throw_compile_error(form, "cannot have anything after an else in a cond");
+    }
+
+    if (test.is_symbol() && symbol_string(test) == "else") {
+      got_else = true;
+    }
+
+    if (got_else) {
+      // just set the output to this.
+      Val* case_result = get_none();
+      for_each_in_list(clauses, [&](const goos::Object& clause) {
+        case_result = compile_error_guard(clause, env);
+      });
+
+      case_result_types.push_back(case_result->type());
+
+      // optimization - if we get junk, don't bother moving it, just leave junk in return.
+      if (!is_none(case_result)) {
+        env->emit(std::make_unique<IR_RegSet>(result, case_result->to_gpr(env)));
+      }
+
+    } else {
+      // CONDITION CHECK
+      auto condition = compile_condition(test, env, true);
+
+      // BRANCH FWD
+      auto branch_ir = std::make_unique<IR_ConditionalBranch>(condition, Label());
+      auto branch_ir_ref = branch_ir.get();
+      branch_ir->mark_as_resolved();
+      env->emit(std::move(branch_ir));
+
+      // CODE
+      Val* case_result = get_none();
+      for_each_in_list(clauses, [&](const goos::Object& clause) {
+        case_result = compile_error_guard(clause, env);
+      });
+
+      case_result_types.push_back(case_result->type());
+      if (!is_none(case_result)) {
+        env->emit(std::make_unique<IR_RegSet>(result, case_result->to_gpr(env)));
+      }
+
+      // GO TO END
+      auto ir_goto_end = std::make_unique<IR_GotoLabel>(end_label);
+      env->emit(std::move(ir_goto_end));
+
+      // PATCH BRANCH FWD
+      branch_ir_ref->label.idx = fenv->code().size();
+    }
+  });
+
+  if (!got_else) {
+    // if no else, clause, return #f.  But don't retype.  I don't know how I feel about this typing
+    // setup.
+    auto get_false = std::make_unique<IR_LoadSymbolPointer>(result, "#f");
+    env->emit(std::move(get_false));
+  }
+
+  result->set_type(m_ts.lowest_common_ancestor(case_result_types));
+
+  // PATCH END
+  end_label->idx = fenv->code().size();
+
+  return result;
+}
\ No newline at end of file
diff --git a/goalc/compiler/compilation/Define.cpp b/goalc/compiler/compilation/Define.cpp
index 9de38d2d1..bb2419332 100644
--- a/goalc/compiler/compilation/Define.cpp
+++ b/goalc/compiler/compilation/Define.cpp
@@ -60,4 +60,43 @@ Val* Compiler::compile_define_extern(const goos::Object& form, const goos::Objec
   }
   m_symbol_types[symbol_string(sym)] = new_type;
   return get_none();
+}
+
+Val* Compiler::compile_set(const goos::Object& form, const goos::Object& rest, Env* env) {
+  auto args = get_va(form, rest);
+  va_check(form, args, {{}, {}}, {});
+
+  auto& destination = args.unnamed.at(0);
+  auto source = compile_error_guard(args.unnamed.at(1), env)->to_reg(env);
+
+  if (destination.is_symbol()) {
+    // destination is just a symbol, so it's either a lexical variable or a global.
+
+    // first, attempt a lexical set:
+    auto lex_place = env->lexical_lookup(destination);
+    if (lex_place) {
+      // typecheck and set!
+      typecheck(form, lex_place->type(), source->type(), "set! lexical variable");
+      env->emit(std::make_unique<IR_RegSet>(lex_place, source));
+      return source;
+    } else {
+      // try to set symbol
+      auto existing = m_symbol_types.find(destination.as_symbol()->name);
+      if (existing == m_symbol_types.end()) {
+        throw_compile_error(
+            form, "could not find something called " + symbol_string(destination) + " to set!");
+      } else {
+        typecheck(form, existing->second, source->type(), "set! global symbol");
+        auto fe = get_parent_env_of_type<FunctionEnv>(env);
+        auto sym_val =
+            fe->alloc_val<SymbolVal>(symbol_string(destination), m_ts.make_typespec("symbol"));
+        auto result_in_gpr = source->to_gpr(env);
+        env->emit(std::make_unique<IR_SetSymbolValue>(sym_val, result_in_gpr));
+        return result_in_gpr;
+      }
+    }
+  } else {
+    throw_compile_error(form, "Set not implemented for this yet");
+  }
+  assert(false);
 }
\ No newline at end of file
diff --git a/goalc/compiler/compilation/Macro.cpp b/goalc/compiler/compilation/Macro.cpp
index 0ad768050..8116ed1cb 100644
--- a/goalc/compiler/compilation/Macro.cpp
+++ b/goalc/compiler/compilation/Macro.cpp
@@ -115,4 +115,22 @@ Val* Compiler::compile_defglobalconstant(const goos::Object& form,
   m_goos.global_environment.as_env()->vars[sym] = value;
 
   return get_none();
+}
+
+Val* Compiler::compile_mlet(const goos::Object& form, const goos::Object& rest, Env* env) {
+  auto defs = pair_car(rest);
+  auto body = pair_cdr(rest);
+
+  auto fenv = get_parent_env_of_type<FunctionEnv>(env);
+  auto menv = fenv->alloc_env<SymbolMacroEnv>(env);
+
+  for_each_in_list(defs, [&](const goos::Object& o) {
+    auto def_args = get_va(form, o);
+    va_check(form, def_args, {goos::ObjectType::SYMBOL, {}}, {});
+    menv->macros[def_args.unnamed.at(0).as_symbol()] = def_args.unnamed.at(1);
+  });
+
+  Val* result = get_none();
+  for_each_in_list(body, [&](const goos::Object& o) { result = compile_error_guard(o, menv); });
+  return result;
 }
\ No newline at end of file
diff --git a/goalc/compiler/compilation/Math.cpp b/goalc/compiler/compilation/Math.cpp
index 2fa863405..84de857ab 100644
--- a/goalc/compiler/compilation/Math.cpp
+++ b/goalc/compiler/compilation/Math.cpp
@@ -48,7 +48,7 @@ Val* Compiler::number_to_integer(Val* in, Env* env) {
   } else if (is_integer(ts)) {
     return in;
   } else {
-    assert(false);
+    throw std::runtime_error("Can't convert " + in->print() + " to an integer.");
   }
 }
 
@@ -215,12 +215,31 @@ Val* Compiler::compile_div(const goos::Object& form, const goos::Object& rest, E
   auto first_type = first_val->type();
   auto math_type = get_math_mode(first_type);
   switch (math_type) {
-    case MATH_FLOAT:
+    case MATH_INT: {
+      auto fe = get_parent_env_of_type<FunctionEnv>(env);
+      auto first_thing = first_val->to_gpr(env);
+      auto result = env->make_ireg(first_type, emitter::RegKind::GPR);
+      env->emit(std::make_unique<IR_RegSet>(result, first_thing));
 
-    {
+      IRegConstraint result_rax_constraint;
+      result_rax_constraint.instr_idx = fe->code().size() - 1;
+      result_rax_constraint.ireg = result->ireg();
+      result_rax_constraint.desired_register = emitter::RAX;
+      fe->constrain(result_rax_constraint);
+
+      env->emit(std::make_unique<IR_IntegerMath>(
+          IntegerMathKind::IDIV_32, result,
+          to_math_type(compile_error_guard(args.unnamed.at(1), env), math_type, env)->to_gpr(env)));
+      return result;
+    }
+
+    case MATH_FLOAT: {
       auto result = env->make_xmm(first_type);
       env->emit(std::make_unique<IR_RegSet>(result, first_val->to_xmm(env)));
-      env->emit(std::make_unique<IR_FloatMath>(FloatMathKind::DIV_SS, result, to_math_type(compile_error_guard(args.unnamed.at(1), env), math_type, env)->to_xmm(env))));
+      env->emit(std::make_unique<IR_FloatMath>(
+          FloatMathKind::DIV_SS, result,
+          to_math_type(compile_error_guard(args.unnamed.at(1), env), math_type, env)->to_xmm(env)));
+      return result;
     }
 
     case MATH_INVALID:
diff --git a/goalc/main.cpp b/goalc/main.cpp
index b86bda898..a01b20a3a 100644
--- a/goalc/main.cpp
+++ b/goalc/main.cpp
@@ -4,7 +4,7 @@
 int main(int argc, char** argv) {
   (void)argc;
   (void)argv;
-  printf("goal compiler\n");
+  printf("GOAL Compiler\n");
 
   Compiler compiler;
   compiler.execute_repl();
diff --git a/test/test_compiler_and_runtime.cpp b/test/test_compiler_and_runtime.cpp
index 882bad524..3d6d0ba95 100644
--- a/test/test_compiler_and_runtime.cpp
+++ b/test/test_compiler_and_runtime.cpp
@@ -225,6 +225,11 @@ TEST(CompilerAndRuntime, CompilerTests) {
   runner.run_test("test-sub-1.gc", {"4\n"});
   runner.run_test("test-sub-2.gc", {"4\n"});
   runner.run_test("test-mul-1.gc", {"-12\n"});
+  runner.run_test("test-three-reg-add.gc", {"7\n"});
+  runner.run_test("test-three-reg-sub.gc", {"3\n"});
+  runner.run_test("test-three-reg-mult.gc", {"3\n"});
+  runner.run_test("test-div-1.gc", {"6\n"});
+  runner.run_test("test-div-2.gc", {"7\n"});
 
   expected = "test-string";
   runner.run_test("test-string-symbol.gc", {expected}, expected.size());
@@ -234,6 +239,15 @@ TEST(CompilerAndRuntime, CompilerTests) {
   // float
   runner.run_test("test-floating-point-1.gc", {"1067316150\n"});
 
+  runner.run_test("test-mlet.gc", {"10\n"});
+  runner.run_test("test-set-symbol.gc", {"22\n"});
+  runner.run_test("test-defsmacro-defgmacro.gc", {"20\n"});
+  runner.run_test("test-desfun.gc", {"4\n"});
+
+  runner.run_test("test-factorial-recursive.gc", {"3628800\n"});
+  runner.run_test("test-factorial-loop.gc", {"3628800\n"});
+  runner.run_test("test-protect.gc", {"33\n"});
+
   compiler.shutdown_target();
   runtime_thread.join();
   runner.print_summary();