diff --git a/.travis.yml b/.travis.yml
index 3c2656d5..938b01f5 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,7 +1,13 @@
 language: c
+os:
+ - osx
+ - linux
 compiler:
   - gcc
   - clang
+env:
+  - WREN_OPTIONS="" CI_ARCHS="ci_32 ci_64"
+  - WREN_OPTIONS="-DWREN_NAN_TAGGING=0" CI_ARCHS="ci_64"
 # Travis VMs are 64-bit but we compile both for 32 and 64 bit. To enable the
 # 32-bit builds to work, we need gcc-multilib.
 addons:
@@ -10,4 +16,4 @@ addons:
     - gcc-multilib
     - g++-multilib
 sudo: false # Enable container-based builds.
-script: make all && make test
+script: make WREN_CFLAGS=${WREN_OPTIONS} ${CI_ARCHS}
diff --git a/Makefile b/Makefile
index f8bdb84b..c2347b99 100644
--- a/Makefile
+++ b/Makefile
@@ -44,6 +44,28 @@ all: debug release
 	$(V) $(MAKE) -f util/wren.mk MODE=debug ARCH=64
 	$(V) $(MAKE) -f util/wren.mk MODE=debug LANG=cpp ARCH=64
 
+ci: ci_32 ci_64
+
+ci_32:
+	$(V) $(MAKE) -f util/wren.mk MODE=debug   LANG=c   ARCH=32 vm cli test
+	$(V) ./util/test.py --suffix=d-32 $(suite)
+	$(V) $(MAKE) -f util/wren.mk MODE=debug   LANG=cpp ARCH=32 vm cli test
+	$(V) ./util/test.py --suffix=d-cpp-32 $(suite)
+	$(V) $(MAKE) -f util/wren.mk MODE=release LANG=c   ARCH=32 vm cli test
+	$(V) ./util/test.py --suffix=-32 $(suite)
+	$(V) $(MAKE) -f util/wren.mk MODE=release LANG=cpp ARCH=32 vm cli test
+	$(V) ./util/test.py --suffix=-cpp-32 $(suite)
+
+ci_64:
+	$(V) $(MAKE) -f util/wren.mk MODE=debug   LANG=c   ARCH=64 vm cli test
+	$(V) ./util/test.py --suffix=d-64 $(suite)
+	$(V) $(MAKE) -f util/wren.mk MODE=debug   LANG=cpp ARCH=64 vm cli test
+	$(V) ./util/test.py --suffix=d-cpp-64 $(suite)
+	$(V) $(MAKE) -f util/wren.mk MODE=release LANG=c   ARCH=64 vm cli test
+	$(V) ./util/test.py --suffix=-64 $(suite)
+	$(V) $(MAKE) -f util/wren.mk MODE=release LANG=cpp ARCH=64 vm cli test
+	$(V) ./util/test.py --suffix=-cpp-64 $(suite)
+
 # Remove all build outputs and intermediate files. Does not remove downloaded
 # dependencies. Use cleanall for that.
 clean:
@@ -80,4 +102,4 @@ gh-pages: docs
 amalgamation: src/include/wren.h src/vm/*.h src/vm/*.c
 	./util/generate_amalgamation.py > build/wren.c
 
-.PHONY: all amalgamation builtin clean debug docs gh-pages release test vm watchdocs
+.PHONY: all amalgamation builtin clean debug docs gh-pages release test vm watchdocs ci ci_32 ci_64
diff --git a/example/syntax.wren b/example/syntax.wren
index bb60e35b..8e2f5d54 100644
--- a/example/syntax.wren
+++ b/example/syntax.wren
@@ -129,8 +129,10 @@ class Literals is SyntaxExample {
     3.14159
     1.0
     -12.34
-    0xdeadbeef
-    0x1234567890ABCDEF
+    0x1000000
+// Literals larger than 0x1000000 are only valid in 64 bit builds
+//    0xdeadbeef
+//    0x1234567890ABCDEF
   }
 
   strings {
diff --git a/src/vm/wren_core.c b/src/vm/wren_core.c
index 5f1a2007..b1044a9c 100644
--- a/src/vm/wren_core.c
+++ b/src/vm/wren_core.c
@@ -618,7 +618,9 @@ DEF_PRIMITIVE(num_bangeq)
 DEF_PRIMITIVE(num_bitwiseNot)
 {
   // Bitwise operators always work on 32-bit unsigned ints.
-  RETURN_NUM(~(uint32_t)AS_NUM(args[0]));
+  uint64_t wideVal = AS_NUM(args[0]);
+  uint32_t val = wideVal & 0xFFFFFFFF;
+  RETURN_NUM(~(uint32_t)val);
 }
 
 DEF_PRIMITIVE(num_dotDot)
diff --git a/src/vm/wren_value.c b/src/vm/wren_value.c
index 48239a63..fcdecf04 100644
--- a/src/vm/wren_value.c
+++ b/src/vm/wren_value.c
@@ -742,9 +742,16 @@ Value wrenNumToString(WrenVM* vm, double value)
   // Corner case: If the value is NaN, different versions of libc produce
   // different outputs (some will format it signed and some won't). To get
   // reliable output, handle that ourselves.
-  if (value != value) return CONST_STRING(vm, "nan");
-  if (value == INFINITY) return CONST_STRING(vm, "infinity");
-  if (value == -INFINITY) return CONST_STRING(vm, "-infinity");
+  switch (fpclassify(value))
+  {
+  case FP_INFINITE:
+    if (signbit(value))
+      return CONST_STRING(vm, "-infinity");
+    else
+      return CONST_STRING(vm, "infinity");
+  case FP_NAN:
+    return CONST_STRING(vm, "nan");
+  }
 
   // This is large enough to hold any double converted to a string using
   // "%.14g". Example:
diff --git a/test/api/slots.c b/test/api/slots.c
index da9cea68..c82b61c2 100644
--- a/test/api/slots.c
+++ b/test/api/slots.c
@@ -19,7 +19,7 @@ static void getSlots(WrenVM* vm)
   if (length != 5) result = false;
   if (memcmp(bytes, "by\0te", length) != 0) result = false;
 
-  if (wrenGetSlotDouble(vm, 3) != 12.34) result = false;
+  if (wrenGetSlotDouble(vm, 3) != 1.5) result = false;
   if (strcmp(wrenGetSlotString(vm, 4), "str") != 0) result = false;
   
   WrenHandle* handle = wrenGetSlotHandle(vm, 5);
@@ -28,13 +28,14 @@ static void getSlots(WrenVM* vm)
   {
     // Otherwise, return the value so we can tell if we captured it correctly.
     wrenSetSlotHandle(vm, 0, handle);
-    wrenReleaseHandle(vm, handle);
   }
   else
   {
     // If anything failed, return false.
     wrenSetSlotBool(vm, 0, false);
   }
+
+  wrenReleaseHandle(vm, handle);
 }
 
 static void setSlots(WrenVM* vm)
@@ -43,7 +44,7 @@ static void setSlots(WrenVM* vm)
   
   wrenSetSlotBool(vm, 1, true);
   wrenSetSlotBytes(vm, 2, "by\0te", 5);
-  wrenSetSlotDouble(vm, 3, 12.34);
+  wrenSetSlotDouble(vm, 3, 1.5);
   wrenSetSlotString(vm, 4, "str");
   
   // TODO: wrenSetSlotNull().
@@ -57,21 +58,22 @@ static void setSlots(WrenVM* vm)
   const char* bytes = wrenGetSlotBytes(vm, 2, &length);
   if (length != 5) result = false;
   if (memcmp(bytes, "by\0te", length) != 0) result = false;
-  
-  if (wrenGetSlotDouble(vm, 3) != 12.34) result = false;
+
+  if (wrenGetSlotDouble(vm, 3) != 1.5) result = false;
   if (strcmp(wrenGetSlotString(vm, 4), "str") != 0) result = false;
 
   if (result)
   {
     // Move the value into the return position.
     wrenSetSlotHandle(vm, 0, handle);
-    wrenReleaseHandle(vm, handle);
   }
   else
   {
     // If anything failed, return false.
     wrenSetSlotBool(vm, 0, false);
   }
+
+  wrenReleaseHandle(vm, handle);
 }
 
 static void slotTypes(WrenVM* vm)
diff --git a/test/api/slots.wren b/test/api/slots.wren
index ef0f8d79..2a8c7219 100644
--- a/test/api/slots.wren
+++ b/test/api/slots.wren
@@ -18,7 +18,7 @@ foreign class ForeignType {
 System.print(Slots.noSet == Slots) // expect: true
 
 var value = ["value"]
-System.print(Slots.getSlots(true, "by\0te", 12.34, "str", value) == value)
+System.print(Slots.getSlots(true, "by\0te", 1.5, "str", value) == value)
 // expect: true
 
 System.print(Slots.setSlots(value, 0, 0, 0) == value)
diff --git a/test/core/number/cos.wren b/test/core/number/cos.wren
index b7672271..74f0db30 100644
--- a/test/core/number/cos.wren
+++ b/test/core/number/cos.wren
@@ -3,4 +3,4 @@ System.print(Num.pi.cos)        // expect: -1
 System.print((2 * Num.pi).cos)  // expect: 1
 
 // this should of course be 0, but it's not that precise
-System.print((Num.pi / 2).cos)  // expect: 6.1232339957368e-17
+System.print((Num.pi / 2).cos.abs < 1.0e-16) // expect: true
diff --git a/test/core/number/sin.wren b/test/core/number/sin.wren
index e83c1073..f0a1d7a9 100644
--- a/test/core/number/sin.wren
+++ b/test/core/number/sin.wren
@@ -2,5 +2,5 @@ System.print(0.sin)             // expect: 0
 System.print((Num.pi / 2).sin)  // expect: 1
 
 // these should of course be 0, but it's not that precise
-System.print(Num.pi.sin)        // expect: 1.2246467991474e-16
-System.print((2 * Num.pi).sin)  // expect: -2.4492935982947e-16
+System.print(Num.pi.sin.abs < 1.0e-15)        // expect: true
+System.print((2 * Num.pi).sin.abs < 1.0e-15)  // expect: true
diff --git a/test/os/process/all_arguments.wren b/test/os/process/all_arguments.wren
index efb55aca..47542a58 100644
--- a/test/os/process/all_arguments.wren
+++ b/test/os/process/all_arguments.wren
@@ -5,7 +5,7 @@ System.print(args is List) // expect: true
 System.print(args.count)   // expect: 2
 
 // Includes wren executable and file being run.
-System.print(args[0].endsWith("wrend")) // expect: true
+System.print(args[0].contains("wren")) // expect: true
 System.print(args[1]) // expect: test/os/process/all_arguments.wren
 
 // TODO: Test passing additional args once we have an API to spawn a process.
diff --git a/util/libuv.py b/util/libuv.py
index 00272cf3..b2f23a8b 100755
--- a/util/libuv.py
+++ b/util/libuv.py
@@ -11,7 +11,7 @@ import shutil
 import subprocess
 import sys
 
-LIB_UV_VERSION = "v1.8.0"
+LIB_UV_VERSION = "v1.10.0"
 LIB_UV_DIR = "deps/libuv"
 
 def python2_binary():
diff --git a/util/test.py b/util/test.py
index cdd033ed..e9b3b19d 100755
--- a/util/test.py
+++ b/util/test.py
@@ -2,6 +2,7 @@
 
 from __future__ import print_function
 
+from argparse import ArgumentParser
 from collections import defaultdict
 from os import listdir
 from os.path import abspath, basename, dirname, isdir, isfile, join, realpath, relpath, splitext
@@ -10,10 +11,22 @@ from subprocess import Popen, PIPE
 import sys
 from threading import Timer
 
+parser = ArgumentParser()
+parser.add_argument('--suffix', default='d')
+parser.add_argument('suite', nargs='?')
+
+args = parser.parse_args(sys.argv[1:])
+
+config=args.suffix.lstrip('d')
+is_debug=args.suffix.startswith('d')
+config_dir=("debug" if is_debug else "release") + config
 # Runs the tests.
 WREN_DIR = dirname(dirname(realpath(__file__)))
-WREN_APP = join(WREN_DIR, 'bin', 'wrend')
-TEST_APP = join(WREN_DIR, 'build', 'debug', 'test', 'wrend')
+WREN_APP = join(WREN_DIR, 'bin', 'wren' + args.suffix)
+TEST_APP = join(WREN_DIR, 'build', config_dir, 'test', 'wren' + args.suffix)
+
+print("WREN_APP=" + WREN_APP)
+print("TEST_APP=" + TEST_APP)
 
 EXPECT_PATTERN = re.compile(r'// expect: ?(.*)')
 EXPECT_ERROR_PATTERN = re.compile(r'// expect error(?! line)')
@@ -114,7 +127,7 @@ class Test:
     test_arg = self.path
     proc = Popen([app, test_arg], stdin=PIPE, stdout=PIPE, stderr=PIPE)
 
-    # If a test takes longer than two seconds, kill it.
+    # If a test takes longer than five seconds, kill it.
     #
     # This is mainly useful for running the tests while stress testing the GC,
     # which can make a few pathological tests much slower.
@@ -123,7 +136,7 @@ class Test:
       timed_out[0] = True
       p.kill()
 
-    timer = Timer(2, kill_process, [proc])
+    timer = Timer(5, kill_process, [proc])
 
     try:
       timer.start()
@@ -313,9 +326,9 @@ def run_script(app, path, type):
     return
 
   # Check if we are just running a subset of the tests.
-  if len(sys.argv) == 2:
+  if args.suite:
     this_test = relpath(path, join(WREN_DIR, 'test'))
-    if not this_test.startswith(sys.argv[1]):
+    if not this_test.startswith(args.suite):
       return
 
   # Update the status line.
diff --git a/util/wren.mk b/util/wren.mk
index 2ada261c..efdef641 100644
--- a/util/wren.mk
+++ b/util/wren.mk
@@ -42,6 +42,7 @@ ifeq ($(VERBOSE),1)
 	V :=
 endif
 
+C_OPTIONS := $(WREN_CFLAGS)
 C_WARNINGS := -Wall -Wextra -Werror -Wno-unused-parameter
 # Wren uses callbacks heavily, so -Wunused-parameter is too painful to enable.