diff --git a/Makefile b/Makefile
index 6a46c67..cfd75dd 100644
--- a/Makefile
+++ b/Makefile
@@ -19,7 +19,7 @@ include $(DEVKITARM)/3ds_rules
 #---------------------------------------------------------------------------------
 export TARGET		:=	$(shell basename $(CURDIR))
 BUILD		:=	build
-SOURCES		:=	source source/tests source/tests/fs
+SOURCES		:=	source source/tests source/tests/fs source/tests/cpu
 DATA		:=	data
 INCLUDES	:=	source #include
 
diff --git a/source/main.cpp b/source/main.cpp
index 68731a7..0219966 100644
--- a/source/main.cpp
+++ b/source/main.cpp
@@ -4,10 +4,12 @@
 
 #include "output.h"
 #include "tests/fs/fs.h"
+#include "tests/cpu/cputests.h"
 
 static unsigned int testCounter = 0;
 static void (*tests[]) (void) = {
-    FS::TestAll
+    FS::TestAll,
+    CPU::Integer::TestAll
 };
 
 int main()
diff --git a/source/tests/cpu/cputests.h b/source/tests/cpu/cputests.h
new file mode 100644
index 0000000..660f3b3
--- /dev/null
+++ b/source/tests/cpu/cputests.h
@@ -0,0 +1,7 @@
+#pragma once
+
+namespace CPU {
+namespace Integer {
+void TestAll();
+}
+}
diff --git a/source/tests/cpu/integer.cpp b/source/tests/cpu/integer.cpp
new file mode 100644
index 0000000..a066689
--- /dev/null
+++ b/source/tests/cpu/integer.cpp
@@ -0,0 +1,104 @@
+#include <limits>
+#include <string>
+#include "output.h"
+#include "tests/test.h"
+
+namespace CPU {
+namespace Integer {
+
+// ADD variants
+static bool Add() {
+    unsigned int output = 0;
+    unsigned int rm = 0;
+    unsigned int rn = 0;
+
+    // Generic addition
+    asm volatile ("LDR r0, =420\n"
+                  "LDR r1, =69\n"
+                  "ADD %[out], r0, r1" : [out] "=r"(output));
+    if (output != 489)
+        return false;
+
+    // ADD overflow (unsigned)
+    rm = std::numeric_limits<unsigned int>::max();
+    rn = 1;
+    asm volatile ("ADD %[out], %[Rm], %[Rn]" : [out] "=r"(output) : [Rm] "r"(rm), [Rn] "r"(rn));
+    if (output != 0)
+        return false;
+
+    // TODO: ADC, ADCS, ADDW, and ADDS variants.
+
+    return true;
+}
+
+// SUB variants
+static bool Sub() {
+    unsigned int output;
+
+    // Generic subtraction.
+    asm volatile ("LDR r0, =489\n"
+                  "SUB %[out], r0, #69" : [out] "=r"(output));
+    if (output != 420)
+        return false;
+
+    // Subtract overflow (0 - 1).
+    asm volatile ("MOV r0, #0\n"
+                  "SUB %[out], r0, #1" : [out] "=r"(output));
+    if (output != std::numeric_limits<unsigned int>::max())
+        return false;
+
+    // TODO: SUBS, etc.
+
+    return true;
+}
+
+// MUL variants
+static bool Mul() {
+    unsigned int output;
+
+    // Multiply by loaded registers.
+    asm volatile ("MOV r0, #20\n"
+                  "MOV r1, #21\n"
+                  "MUL %[out], r0, r1" : [out] "=r"(output));
+    if (output != 420)
+        return false;
+
+    // TODO: Other MUL variants.
+
+    return true;
+}
+
+// SASX
+static bool Sasx() {
+    unsigned int output;
+    unsigned int rm = std::numeric_limits<unsigned int>::max();
+    unsigned int rn = rm - 4000;
+
+    asm volatile ("SASX %[out], %[Rm], %[Rn]" : [out] "=r"(output) : [Rm] "r"(rm), [Rn] "r"(rn));
+
+    return (output == 4032692224);
+}
+
+// SSAX
+static bool Ssax() {
+    unsigned int output;
+    unsigned int rm = std::numeric_limits<unsigned int>::max();
+    unsigned int rn = rm - 4000;
+
+    asm volatile ("SSAX %[out], %[Rm], %[Rn]" : [out] "=r"(output) : [Rm] "r"(rm), [Rn] "r"(rn));
+
+    return (output == 262209534);
+}
+
+void TestAll() {
+    const std::string tag = "Integer";
+
+    Test(tag, "ADD", &Add);
+    Test(tag, "SUB", &Sub);
+    Test(tag, "MUL", &Mul);
+    Test(tag, "SASX", &Sasx);
+    Test(tag, "SSAX", &Ssax);
+}
+
+}
+}