diff --git a/test6502.cpp b/test6502.cpp
new file mode 100644
index 0000000..5cbc10b
--- /dev/null
+++ b/test6502.cpp
@@ -0,0 +1,90 @@
+#include <array>
+#include <algorithm>
+#include <cstdio>
+#include "cpu6502.h"
+#include "dis6502.h"
+
+struct dummyclock
+{
+    int cycles = 0;
+    void add_cpu_cycles(int N) {
+        cycles += N;
+    }
+};
+
+struct bus
+{
+    std::array<uint8_t, 64 * 1024> memory;
+    bus()
+    {
+        std::fill(memory.begin(), memory.end(), 0xA5);
+    }
+    uint8_t read(uint16_t addr) const
+    {
+        printf("read 0x%04X yields 0x%02X\n", addr, memory[addr]);
+        return memory[addr];
+    }
+    void write(uint16_t addr, uint8_t data)
+    {
+        printf("write 0x%02X to 0x%04X\n", data, addr);
+        memory[addr] = data;
+    }
+};
+
+template<class CLK, class BUS>
+void print_cpu_state(const CPU6502<CLK, BUS>& cpu)
+{
+    printf("6502: A:%02X X:%02X Y:%02X P:", cpu.a, cpu.x, cpu.y);
+    printf("%s", (cpu.p & cpu.N) ? "N" : "n");
+    printf("%s", (cpu.p & cpu.V) ? "V" : "v");
+    printf("-");
+    printf("%s", (cpu.p & cpu.B) ? "B" : "b");
+    printf("%s", (cpu.p & cpu.D) ? "D" : "d");
+    printf("%s", (cpu.p & cpu.I) ? "I" : "i");
+    printf("%s", (cpu.p & cpu.Z) ? "Z" : "z");
+    printf("%s ", (cpu.p & cpu.C) ? "C" : "c");
+    printf("S:%02X ", cpu.s);
+    printf("PC:%04X\n", cpu.pc);
+}
+
+template<class BUS>
+std::string read_bus_and_disassemble(const BUS &bus, int pc)
+{
+    uint8_t buf[4];
+    buf[0] = bus.read(pc + 0);
+    buf[1] = bus.read(pc + 1);
+    buf[2] = bus.read(pc + 2);
+    buf[3] = bus.read(pc + 3);
+    auto [bytes, dis] = disassemble_6502(pc - 1, buf);
+    return dis;
+}
+
+int main(int argc, const char **argv)
+{
+    bus machine;
+
+    FILE *testbin = fopen("6502_functional_test.bin", "rb");
+    assert(testbin);
+    fseek(testbin, 0, SEEK_END);
+    long length = ftell(testbin);
+    fseek(testbin, 0, SEEK_SET);
+    fread(machine.memory.data(), 1, length, testbin);
+    fclose(testbin);
+
+    dummyclock clock;
+
+    CPU6502<dummyclock, bus> cpu(clock, machine);
+
+    cpu.cycle();
+
+    cpu.pc = 0x400;
+
+    uint16_t oldpc = 0x0;
+    do {
+        print_cpu_state(cpu);
+        printf("%s\n", read_bus_and_disassemble(machine, cpu.pc).c_str());
+        oldpc = cpu.pc;
+        cpu.cycle();
+    } while(cpu.pc != oldpc);
+    print_cpu_state(cpu);
+}