diff --git a/python-scripts/dsp_instruction_test.py b/python-scripts/dsp_instruction_test.py
new file mode 100755
index 0000000..b074372
--- /dev/null
+++ b/python-scripts/dsp_instruction_test.py
@@ -0,0 +1,302 @@
+#!/usr/bin/env python3
+
+# Run this from a clean Xbox environment (= not while a game is running)
+# NXDK-RDT is a good environment
+
+from xboxpy import *
+
+import json
+import sys
+import time
+
+reserved_words = 0x20
+
+def get_word(s):
+  #FIXME: Assert type is string or int
+  s = str(s)
+  s = s.strip()
+  s = s.replace('$', '0x')
+  s = s.lower()
+  if s[0:2] == "0x":
+    return int(s[2:], 16)
+  else:
+    return int(s, 10)
+
+def dsp_stop():
+  # Reset GP and GP DSP
+  apu.write_u32(NV_PAPU_GPRST, 0)
+  time.sleep(0.1) # FIXME: Not sure if DSP reset is synchronous, so we wait for now
+
+  # Enable GP first, otherwise memory writes won't be handled
+  apu.write_u32(NV_PAPU_GPRST, NV_PAPU_GPRST_GPRST)
+
+
+def dsp_allocate_scratch_space(page_count):
+
+  # Allocate some scratch space (at least 2 pages!)
+  #FIXME: Why did I put: "(at least 2 pages!)" ?
+  assert(page_count >= 2)
+
+  # Apparently NV_PAPU_GPSADDR has to be aligned to 0x4000 bytes?!
+  #FIXME: Free memory after running
+  page_head = ke.MmAllocateContiguousMemoryEx(4096, 0x00000000, 0xFFFFFFFF, 0x4000, ke.PAGE_READWRITE)
+  page_head_p = ke.MmGetPhysicalAddress(page_head)
+  apu.write_u32(NV_PAPU_GPSADDR, page_head_p)
+  page_base = ke.MmAllocateContiguousMemory(4096 * page_count)
+  for i in range(0, page_count):
+    write_u32(page_head + i * 8 + 0, ke.MmGetPhysicalAddress(page_base + 0x1000 * i))
+    write_u32(page_head + i * 8 + 4, 0) # Control
+
+  # I'm not sure if this is off-by-one (maybe `page_count - 1`)
+  apu.write_u32(NV_PAPU_GPSMAXSGE, page_count)
+
+  return page_base
+
+def dsp_start():
+
+  # Set frame duration (?!)
+  if True:
+    apu.write_u32(NV_PAPU_SECTL, 3 << 3)
+
+  # Mark GP as ready?
+  NV_PAPU_GPIDRDY = 0x3FF10
+  NV_PAPU_GPIDRDY_GPSETIDLE = (1 << 0)
+  apu.write_u32(NV_PAPU_GPIDRDY, NV_PAPU_GPIDRDY_GPSETIDLE)
+
+  # Clear interrupts
+  NV_PAPU_GPISTS = 0x3FF14
+  apu.write_u32(NV_PAPU_GPISTS, 0xFF)
+
+  # Now run GP DSP by removing reset bit
+  apu.write_u32(NV_PAPU_GPRST, NV_PAPU_GPRST_GPRST | NV_PAPU_GPRST_GPDSPRST)
+  time.sleep(0.1)
+
+def dsp_homebrew(tests):
+  #FIXME: Pass dsp object which provides all the device details and registers instead
+
+  # Stop the running DSP
+  print("Stopping DSP")
+  dsp_stop()
+
+  # Allocate new scratch space
+  print("Allocating DSP scratch space")
+  page_base = dsp_allocate_scratch_space(20)
+
+  # Start with empty code
+  print("Generating DSP code")
+  code = ""
+
+  # We reserve some program words (jump targets, as magic for p-word injection)
+  code += "nop\n" * reserved_words
+
+  # Setup memory registers
+  #FIXME: Do this before every writeback / address outputs directly
+  code += "\n; Memory register setup\n\n"
+  code += "movec #$FFFF, M7\n"
+  code += "move #$100, R7\n"
+  code += "move #1, N7\n"
+  code += "nop\n"
+
+  # Generate each test
+  r7 = 0x100 #FIXME: X:0 seems to be used during DSP reset?!
+  n7 = 1
+  for t in tests:
+    i = t[0]
+    p = t[1]
+    o = t[2]
+
+    code += "\n; Test\n\n"
+
+    #FIXME: Allow only 24 bit registers
+    #       - Replace 'a' by ('a2', 'a1', 'a0')
+    #       - Replace 'b' by ('b2', 'b1', 'b0')
+
+    control_regs = [
+      "vba", "sr", "omr", "sp", "ssh", "ssl", "la", "lc",
+      "m0", "m1", "m2", "m3", "m4", "m5", "m6", "m7",
+    ]
+
+    # Add any register which would cause trouble
+    forbidden_regs = [
+      "ssh", # Crash in XQEMU (possibly bug in a56?)
+      "vba", # Caused error in a56
+      "m7", "r7", "n7" # Used for input/output addressing
+    ]
+
+    # Input
+    for k, v in i.items():
+
+      if k.find(':') != -1:
+        print("Memory %s unsupported in setter" % k)
+        space, colon, address = k.partition(':')
+        address = get_word(address)
+
+        for w in v:
+          print("Would have set %s:$%X to 0x%06X" % (space, address, w))
+          address += 1
+
+      elif k.lower() in forbidden_regs:
+        print("Register %s forbidden in setter" % k)
+      else:
+        if k.lower() in control_regs:
+          code += "movec x:(R7)+N7, %s\n" % (k)
+        else:
+          code += "move x:(R7)+N7, %s\n" % (k)
+        apu.write_u32(NV_PAPU_GPXMEM + r7*4, v)
+        r7 += n7
+        code += "nop\n" # Avoid hazards
+
+    # Processing, while avoiding the mix any of the surrounding instructions    
+    code += "nop\n"
+    code += p[0] + "\n"
+    code += "nop\n"
+
+    # Setup memory registers for output
+    code += "movec #$FFFF, M7\n"
+    code += "move #$100, R7\n"
+    code += "move #1, N7\n"
+    code += "nop\n"
+
+    # Output
+    for k in o:
+
+      if k.lower() in forbidden_regs:
+        print("Register %s forbidden in getter" % k)
+        code += "move a0, y:(R7)+N7\n" # Used to advance R7
+      elif k.lower() in control_regs:
+        code += "movec %s, y:(R7)+N7\n" % (k)
+      else:
+        code += "move %s, y:(R7)+N7\n" % (k)
+
+  # Mark results as ready and stick in a loop
+  code += "\n; Result marker\n\n"
+  code += "move #$1337, a\n"
+  code += "move a, y:$0\n"
+  code += "finished_loop\n"
+  code += "  jmp finished_loop"
+
+  # Assemble code and convert the 24 bit words to 32 bit words
+  print("Starting assembler")
+  data = dsp.assemble(code)
+  data = dsp.from24(data)
+
+  # Write code to PMEM, and also inject p-words
+  print("Writing program to DSP")
+  for i in range(0, len(data) // 4):
+    word = int.from_bytes(data[i*4:i*4+4], byteorder='little', signed=False) & 0xFFFFFF
+
+    # Check for the magic jmp, to inject p-words
+    if word & 0xFFF000 == 0x0C0000:
+      jmp_label = word & 0xFFF
+      if jmp_label < reserved_words:
+        word = p[1][jmp_label]
+
+    apu.write_u32(NV_PAPU_GPPMEM + i*4, word)
+    # According to XQEMU, 0x800 * 4 bytes will be loaded from scratch to PMEM at startup.
+    # So just to be sure, let's also write this to the scratch..
+    write_u32(page_base + i*4, word)
+
+  # Set Y:0, so we can see when the program modifies it later
+  apu.write_u32(NV_PAPU_GPYMEM + 0*4, 0x000000)
+  assert(apu.read_u32(NV_PAPU_GPYMEM + 0*4) == 0x000000)
+
+  # Run the test
+  print("Running test")
+  dsp_start()
+
+  # Wait until results are ready
+  print("Waiting for test results")
+  while(apu.read_u32(NV_PAPU_GPYMEM + 0*4) != 0x1337):
+    time.sleep(0.5)
+
+  # Read all results from memory
+  print("Reading test results")
+  all_results = []
+  r7 = 0x100
+  n7 = 1
+  for t in tests:
+    i = t[0]
+    p = t[1]
+    o = t[2]
+
+    #FIXME: Verify that inputs were not touched
+
+    # Loop over all outputs
+    results = {}
+    for k in o:
+      results[k] = apu.read_u32(NV_PAPU_GPYMEM + r7*4)
+      r7 += n7
+
+    # Add result for this test
+    all_results += [results]
+
+  # Remove forbidden outputs
+  for k in forbidden_regs:
+    if k in results:
+      del results[k]
+
+  # Return the output
+  return all_results
+
+
+
+
+# Process all tests
+for path in sys.argv[1:]:
+
+  print("")
+  print("Processing '%s'" % path)
+  print("")
+
+  # Load test from file
+  #FIXME: Error checking
+  with open(path, 'rb') as f:
+    source = f.read()
+  test = json.loads(source)
+
+  # Turn all prefixed strings into words
+  new_input = {}
+  for k, v in test['input'].items():
+    if k.find(':') != -1:
+      new_input[k] = [get_word(word) for word in v]
+    else:
+      new_input[k] = get_word(v)
+  new_input
+    
+  # Turn line-array into string
+  new_code = ""
+  inject = []
+  for l in test['code']:
+
+    # Check for raw p-words to inject
+    if l[0] == ":":
+      v = get_word(l[1:])
+      print("Unsupported program-word: 0x%06X" % v)
+      #FIXME: We need some syntax for parallel words?
+      new_code += "jmp <$%X\n" % len(inject)
+      inject += [v]
+      assert(len(inject) <= reserved_words)
+
+    else:
+      new_code += l + "\n"
+
+  #FIXME: This is a legacy format; this weird conversion shouldn't be necessary
+  # Assemble a test
+  tests = [(new_input, (new_code, inject), test['output'])]
+
+  # Run the tests
+  results = dsp_homebrew(tests)
+
+  # Print results
+  print("Finished:")
+  output_json = {} 
+  for r in results:
+    print("")
+    for k, v in r.items():
+      print("%s: 0x%X" % (k, v))
+      output_json[k] = '0x%X' % (v)
+
+  #FIXME: Write to log
+  output_source = json.dumps(output_json, indent=2)
+  with open(path + "-out.json", 'wb') as f:
+    f.write(output_source.encode("utf-8"))
diff --git a/python-scripts/dsp_instruction_tests/code-test.json b/python-scripts/dsp_instruction_tests/code-test.json
new file mode 100644
index 0000000..00c36ed
--- /dev/null
+++ b/python-scripts/dsp_instruction_tests/code-test.json
@@ -0,0 +1,15 @@
+{
+  "input": {
+    "a2": "0x00",
+    "a1": "0x000000",
+    "a0": "0x000000"
+  },
+  "code": [
+    "move #$12, a2",
+    "move #$345678, a1",
+    "move #$9ABCDE, a0"
+  ],
+  "output": [
+    "a2","a1","a0"
+  ]
+}
diff --git a/python-scripts/dsp_instruction_tests/inc_a-test.json b/python-scripts/dsp_instruction_tests/inc_a-test.json
new file mode 100644
index 0000000..8e9eb7b
--- /dev/null
+++ b/python-scripts/dsp_instruction_tests/inc_a-test.json
@@ -0,0 +1,15 @@
+{
+  "input": {
+    "a2": "0x00",
+    "a1": "0x000000",
+    "a0": "0x000000"
+  },
+  "code": [
+    ":0x000008", "; inc a"
+  ],
+  "output": [
+    "a2",
+    "a1",
+    "a0"
+  ]
+}
diff --git a/python-scripts/dsp_instruction_tests/memory-test.json b/python-scripts/dsp_instruction_tests/memory-test.json
new file mode 100644
index 0000000..eb14bd4
--- /dev/null
+++ b/python-scripts/dsp_instruction_tests/memory-test.json
@@ -0,0 +1,13 @@
+{
+  "input": {
+    "x:$10": ["0xFF0012","0x123456"],
+    "x:$20": ["0x789ABC"]
+  },
+  "code": [
+    "move x:$10, x0",
+    "move x0, x:$20"
+  ],
+  "output": [
+    "x0"
+  ]
+}
diff --git a/python-scripts/dsp_instruction_tests/registers-test.json b/python-scripts/dsp_instruction_tests/registers-test.json
new file mode 100644
index 0000000..982373b
--- /dev/null
+++ b/python-scripts/dsp_instruction_tests/registers-test.json
@@ -0,0 +1,16 @@
+{
+  "input": {
+    "a2": "0x00", "a1": "0x000000", "a0": "0x000000"
+  },
+  "code": [],
+  "output": [
+    "vba", "sr", "omr", "sp", "ssh", "ssl", "la", "lc",
+    "a2","a1","a0",
+    "b2","b1","b0",
+    "x0", "x1",
+    "y0", "y1",
+    "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
+    "m0", "m1", "m2", "m3", "m4", "m5", "m6", "m7",
+    "n0", "n1", "n2", "n3", "n4", "n5", "n6", "n7"
+  ]
+}