diff --git a/test/test_dtype.py b/test/test_dtype.py
index 61fedfc6..8b551537 100644
--- a/test/test_dtype.py
+++ b/test/test_dtype.py
@@ -1,11 +1,29 @@
 import unittest
 import numpy as np
-from tinygrad.helpers import getenv, DType, DEBUG, ImageDType, PtrDType
+from tinygrad.helpers import CI, DTYPES_DICT, getenv, DType, DEBUG, ImageDType, PtrDType
 from tinygrad.ops import Device
 from tinygrad.tensor import Tensor, dtypes
-from typing import List, Optional
+from typing import Any, List
 from extra.utils import OSX, temp
-import copy
+
+def is_dtype_supported(dtype: DType):
+  # for GPU, cl_khr_fp16 isn't supported (except now we don't need it!)
+  # for LLVM, it segfaults because it can't link to the casting function
+  if dtype == dtypes.half: return not (CI and Device.DEFAULT in ["GPU", "LLVM"]) and Device.DEFAULT != "WEBGPU" and getenv("CUDACPU") != 1
+  if dtype == dtypes.bfloat16: return False # numpy doesn't support bf16, tested separately in TestBFloat16DType
+  if dtype == dtypes.float64: return Device.DEFAULT not in ["WEBGPU", "METAL"] and not OSX
+  if dtype in [dtypes.int8, dtypes.uint8]: return Device.DEFAULT not in ["WEBGPU"]
+  if dtype in [dtypes.int16, dtypes.uint16]: return Device.DEFAULT not in ["WEBGPU", "TORCH"]
+  if dtype == dtypes.uint32: return Device.DEFAULT not in ["TORCH"]
+  if dtype in [dtypes.int64, dtypes.uint64]: return Device.DEFAULT not in ["WEBGPU", "TORCH"]
+  if dtype == dtypes.bool:
+   # host-shareablity is a requirement for storage buffers, but 'bool' type is not host-shareable
+    if Device.DEFAULT == "WEBGPU": return False
+   # TODO remove triton from here once internal casting is fixed. CAST of fp32s between 0-1 is broken in triton
+    if getenv("TRITON") == 1: return False
+  return True
+
+def get_available_cast_dtypes(dtype: DType) -> List[DType]: return [v for k, v in DTYPES_DICT.items() if v != dtype and is_dtype_supported(v) and not k.startswith("_")] # dont cast internal dtypes
 
 def _test_to_np(a:Tensor, np_dtype, target):
   if DEBUG >= 2: print(a)
@@ -26,31 +44,49 @@ def _assert_eq(tensor:Tensor, target_dtype:DType, target):
     raise AssertionError(f"\ntensor {tensor.numpy()} dtype {tensor.dtype} does not match target {target} with dtype {target_dtype}") from e
 
 def _test_op(fxn, target_dtype:DType, target): _assert_eq(fxn(), target_dtype, target)
-def _test_cast(a:Tensor, target_dtype:DType, target): _test_op(lambda: a.cast(target_dtype), target_dtype, target)
+def _test_cast(a:Tensor, target_dtype:DType): _test_op(lambda: a.cast(target_dtype), target_dtype, a.numpy().astype(target_dtype.np).tolist())
 def _test_bitcast(a:Tensor, target_dtype:DType, target): _test_op(lambda: a.bitcast(target_dtype), target_dtype, target)
 
-# tests no-op casts from source_dtype to target_dtypes
-def _test_casts_from(tensor_contents:List, source_dtype:DType, target_dtypes:List[DType], target_contents:Optional[List]=None):
-  if target_contents is None: target_contents = copy.deepcopy(tensor_contents)
-  list(map(
-    lambda t_dtype: _test_cast(Tensor(tensor_contents, dtype=source_dtype), t_dtype, target_contents),
-    target_dtypes
+class TestDType(unittest.TestCase):
+  DTYPE: Any = None
+  DATA: Any = None
+  @classmethod
+  def setUpClass(cls):
+    if not is_dtype_supported(cls.DTYPE): raise unittest.SkipTest("dtype not supported")
+    cls.DATA = np.random.randint(0, 100, size=10, dtype=cls.DTYPE.np).tolist() if dtypes.is_int(cls.DTYPE) else np.random.choice([True, False], size=10).tolist() if cls.DTYPE == dtypes.bool else np.random.uniform(0, 1, size=10).tolist()
+  def setUp(self):
+    if self.DTYPE is None: raise unittest.SkipTest("base class")
+
+  def test_to_np(self): _test_to_np(Tensor(self.DATA, dtype=self.DTYPE), self.DTYPE.np, np.array(self.DATA, dtype=self.DTYPE.np))
+
+  def test_casts_to(self): list(map(
+    lambda dtype: _test_cast(Tensor(self.DATA, dtype=dtype), self.DTYPE),
+    get_available_cast_dtypes(self.DTYPE)
   ))
-# tests no-op casts from source_dtypes to target_dtype
-def _test_casts_to(tensor_contents:List, source_dtypes:List[DType], target_dtype:DType, target_contents:Optional[List]=None):
-  if target_contents is None: target_contents = copy.deepcopy(tensor_contents)
-  list(map(
-    lambda s_dtype: _test_cast(Tensor(tensor_contents, dtype=s_dtype), target_dtype, target_contents),
-    source_dtypes
+  def test_casts_from(self): list(map(
+    lambda dtype: _test_cast(Tensor(self.DATA, dtype=self.DTYPE), dtype),
+    get_available_cast_dtypes(self.DTYPE)
+  ))
+
+  def test_upcast_ops(self): list(map(
+    lambda dtype: _test_ops(a_dtype=self.DTYPE, b_dtype=dtype, target_dtype=dtype) if dtype.sz > self.DTYPE.sz else None,
+    get_available_cast_dtypes(self.DTYPE)
+  ))
+  def test_upcast_to_ops(self): list(map(
+    lambda dtype: _test_ops(a_dtype=dtype, b_dtype=self.DTYPE, target_dtype=self.DTYPE) if dtype.sz < self.DTYPE.sz else None,
+    get_available_cast_dtypes(self.DTYPE)
   ))
 
 def _test_ops(a_dtype:DType, b_dtype:DType, target_dtype:DType):
+  if not is_dtype_supported(a_dtype) or not is_dtype_supported(b_dtype): raise unittest.SkipTest("dtype not supported")
   _assert_eq(Tensor([1,2,3,4], dtype=a_dtype)+Tensor([1,2,3,4], dtype=b_dtype), target_dtype, [2,4,6,8])
   _assert_eq(Tensor([1,2,3,4], dtype=a_dtype)*Tensor([1,2,3,4], dtype=b_dtype), target_dtype, [1,4,9,16])
   _assert_eq(Tensor([[1,2],[3,4]], dtype=a_dtype)@Tensor.eye(2, dtype=b_dtype), target_dtype, [[1,2],[3,4]])
   _assert_eq(Tensor([1,1,1,1], dtype=a_dtype)+Tensor.ones((4,4), dtype=b_dtype), target_dtype, 2*Tensor.ones(4,4).numpy())
 
 class TestBFloat16DType(unittest.TestCase):
+  def setUp(self):
+    if not is_dtype_supported(dtypes.bfloat16): raise unittest.SkipTest("bfloat16 not supported")
   def test_bf16_to_float(self):
     with self.assertRaises(AssertionError):
       _test_cast(Tensor([100000], dtype=dtypes.bfloat16), dtypes.float32, [100000])
@@ -61,14 +97,12 @@ class TestBFloat16DType(unittest.TestCase):
 
   # torch.tensor([10000, -1, -1000, -10000, 20]).type(torch.bfloat16)
 
-  @unittest.skipIf(Device.DEFAULT not in ["LLVM"], "bf16 only on LLVM")
   def test_bf16(self):
     t = Tensor([10000, -1, -1000, -10000, 20]).cast(dtypes.bfloat16)
     t.realize()
     back = t.cast(dtypes.float32)
     assert tuple(back.numpy().tolist()) == (9984., -1, -1000, -9984, 20)
 
-  @unittest.skipIf(Device.DEFAULT not in ["LLVM"], "bf16 only on LLVM")
   def test_bf16_disk_write_read(self):
     t = Tensor([10000, -1, -1000, -10000, 20]).cast(dtypes.float32)
     t.to(f"disk:{temp('f32')}").realize()
@@ -82,44 +116,20 @@ class TestBFloat16DType(unittest.TestCase):
     back = t.cast(dtypes.float32)
     assert tuple(back.numpy().tolist()) == (9984., -1, -1000, -9984, 20)
 
-# for GPU, cl_khr_fp16 isn't supported (except now we don't need it!)
-# for LLVM, it segfaults because it can't link to the casting function
-@unittest.skipIf((getenv("CI", "") != "" and Device.DEFAULT in ["LLVM"]) or Device.DEFAULT == "WEBGPU", "float16 broken in some CI backends")
-class TestHalfDtype(unittest.TestCase):
-  def test_float16_to_np(self): _test_to_np(Tensor([1,2,3,4], dtype=dtypes.float16), np.float16, [1,2,3,4])
-  def test_casts_to_half(self): _test_casts_to([1,2,3,4], source_dtypes=[dtypes.float32, dtypes.int8, dtypes.uint8], target_dtype=dtypes.float16)
-  def test_casts_from_half(self): _test_casts_from([1,2,3,4], source_dtype=dtypes.float16, target_dtypes=[dtypes.int8, dtypes.uint8, dtypes.float32, dtypes.int32, dtypes.int64])
-  def test_half_upcast_ops(self): _test_ops(a_dtype=dtypes.float16, b_dtype=dtypes.float32, target_dtype=dtypes.float32)
-  def test_upcast_to_half_ops(self): _test_ops(a_dtype=dtypes.int8, b_dtype=dtypes.float16, target_dtype=dtypes.float16)
+class TestHalfDtype(TestDType): DTYPE = dtypes.half
 
-@unittest.skipIf(Device.DEFAULT in ["WEBGPU", "METAL"] or OSX, "float64 is not supported by some backends")
-class TestDoubleDtype(unittest.TestCase):
-  def test_float64_to_np(self): _test_to_np(Tensor([1,2,3,4], dtype=dtypes.double), np.double, [1,2,3,4])
-  def test_casts_to_float64(self): _test_casts_to([1,2,3,4], source_dtypes=[dtypes.float32, dtypes.int32, dtypes.uint8], target_dtype=dtypes.float64)
-  def test_upcast_to_float64_ops(self): _test_ops(a_dtype=dtypes.int8, b_dtype=dtypes.float64, target_dtype=dtypes.float64)
+class TestFloatDType(TestDType): DTYPE = dtypes.float
 
-@unittest.skipIf(Device.DEFAULT == "WEBGPU", "webgpu does not support int8")
-class TestInt8Dtype(unittest.TestCase):
-  def test_int8_to_np(self): _test_to_np(Tensor([1,2,3,4], dtype=dtypes.int8), np.int8, [1,2,3,4])
-  def test_uint8_to_np(self): _test_to_np(Tensor([1,2,3,4], dtype=dtypes.uint8), np.uint8, [1,2,3,4])
-  def test_int64_to_np(self): _test_to_np(Tensor([1,2,3,4], dtype=dtypes.int64), np.int64, [1,2,3,4])
+class TestDoubleDtype(TestDType): DTYPE = dtypes.double
 
-  def test_casts_to_int8(self): _test_casts_from([1,2,3,4], source_dtype=dtypes.float32, target_dtypes=[dtypes.int8, dtypes.uint8, dtypes.int32, dtypes.int64])
-  def test_casts_to_bool_1(self): _test_casts_from([1,2,3,4], source_dtype=dtypes.int8, target_dtypes=[dtypes.bool], target_contents=[True, True, True, True])
-  def test_casts_to_bool_2(self): _test_casts_from([1,0,3,4], source_dtype=dtypes.int8, target_dtypes=[dtypes.bool], target_contents=[True, False, True, True])
-  def test_casts_from_int8(self): _test_casts_from([1,2,3,4], source_dtype=dtypes.int8, target_dtypes=[dtypes.float32, dtypes.uint8, dtypes.int32, dtypes.int64])
-  def test_casts_from_uint8(self): _test_casts_from([1,2,3,4], source_dtype=dtypes.uint8, target_dtypes=[dtypes.float32, dtypes.int8, dtypes.int32, dtypes.int64])
-
-  def test_int8_ops(self): _test_ops(a_dtype=dtypes.int8, b_dtype=dtypes.int8, target_dtype=dtypes.int8)
-  def test_int64_ops(self): _test_ops(a_dtype=dtypes.int64, b_dtype=dtypes.int64, target_dtype=dtypes.int64)
-  def test_int8_upcast_float(self): _test_ops(a_dtype=dtypes.int8, b_dtype=dtypes.float32, target_dtype=dtypes.float32)
-  def test_int8_upcast_int64(self): _test_ops(a_dtype=dtypes.int8, b_dtype=dtypes.int64, target_dtype=dtypes.int64)
-
-  @unittest.skipIf(getenv("CUDA",0)==1, "cuda saturation works differently")
-  @unittest.skipIf(getenv("PTX",0)==1, "cuda saturation doesn't wrap")
+class TestInt8Dtype(TestDType):
+  DTYPE = dtypes.int8
+  @unittest.skipIf(getenv("CUDA",0)==1 or getenv("PTX", 0)==1, "cuda saturation works differently")
   def test_int8_to_uint8_negative(self): _test_op(lambda: Tensor([-1, -2, -3, -4], dtype=dtypes.int8).cast(dtypes.uint8), dtypes.uint8, [255, 254, 253, 252])
 
-  @unittest.skipIf(getenv("PTX",0)==1, "cuda saturation doesn't wrap")
+class TestUint8Dtype(TestDType):
+  DTYPE = dtypes.uint8
+  @unittest.skipIf(getenv("CUDA",0)==1 or getenv("PTX", 0)==1, "cuda saturation works differently")
   def test_uint8_to_int8_overflow(self): _test_op(lambda: Tensor([255, 254, 253, 252], dtype=dtypes.uint8).cast(dtypes.int8), dtypes.int8, [-1, -2, -3, -4])
 
 @unittest.skipIf(Device.DEFAULT not in {"CPU", "TORCH"}, "only bitcast in CPU and TORCH")
@@ -141,23 +151,16 @@ class TestBitCast(unittest.TestCase):
     with self.assertRaises(AssertionError):
       _test_bitcast(Tensor([100000], dtype=dtypes.float32), dtypes.uint8, [100000])
 
-class TestInt32Dtype(unittest.TestCase):
-  def test_int32_to_np(self): _test_to_np(Tensor([1,2,3,4], dtype=dtypes.int32), np.int32, [1,2,3,4])
+class TestInt16Dtype(TestDType): DTYPE = dtypes.int16
+class TestUint16Dtype(TestDType): DTYPE = dtypes.uint16
 
-  @unittest.skipIf(Device.DEFAULT == "WEBGPU", "webgpu does not support int64")
-  def test_casts_to_int32(self): _test_casts_to([1,2,3,4], source_dtypes=[dtypes.float32, dtypes.int64], target_dtype=dtypes.int32)
-  @unittest.skipIf(Device.DEFAULT == "WEBGPU", "webgpu does not support int64")
-  def test_casts_from_int32(self): _test_casts_from([1,2,3,4], source_dtype=dtypes.int32, target_dtypes=[dtypes.float32, dtypes.int64])
+class TestInt32Dtype(TestDType): DTYPE = dtypes.int32
+class TestUint32Dtype(TestDType): DTYPE = dtypes.uint32
 
-  def test_int32_ops(self): _test_ops(a_dtype=dtypes.int32, b_dtype=dtypes.int32, target_dtype=dtypes.int32)
-  def test_int32_upcast_float32(self): _test_ops(a_dtype=dtypes.int32, b_dtype=dtypes.float32, target_dtype=dtypes.float32)
-  @unittest.skipIf(Device.DEFAULT == "WEBGPU", "webgpu does not support int64")
-  def test_int32_upcast_int64(self): _test_ops(a_dtype=dtypes.int32, b_dtype=dtypes.int64, target_dtype=dtypes.int64)
+class TestInt64Dtype(TestDType): DTYPE = dtypes.int64
+class TestUint64Dtype(TestDType): DTYPE = dtypes.uint64
 
-@unittest.skipIf(Device.DEFAULT == "WEBGPU", "host-shareablity is a requirement for storage buffers, but 'bool' type is not host-shareable")
-class TestBoolDtype(unittest.TestCase):
-  def test_casts_from_bool(self): _test_casts_from([0,1,1,0], source_dtype=dtypes.bool, target_dtypes=[dtypes.float32, dtypes.int32])
-  def test_casts_to_bool(self): _test_casts_to([0,1,1,0], source_dtypes=[dtypes.float32, dtypes.int32], target_dtype=dtypes.bool)
+class TestBoolDtype(TestDType): DTYPE = dtypes.bool
 
 class TestEqStrDType(unittest.TestCase):
   def test_image_ne(self):
diff --git a/tinygrad/renderer/llvmir.py b/tinygrad/renderer/llvmir.py
index f01fcaeb..1f0f8243 100644
--- a/tinygrad/renderer/llvmir.py
+++ b/tinygrad/renderer/llvmir.py
@@ -24,7 +24,7 @@ code_for_op: Final[Dict[Op, Callable]] = {
   TernaryOps.WHERE: lambda builder,x,y,z: builder.select(builder.fcmp_unordered("!=", x, ir.Constant(ir.FloatType(), 0), flags=LLVM_FAST_MATH_FLAGS) if isinstance(x.type, ir.FloatType) else builder.trunc(x, ir.IntType(1)), y, z, flags=LLVM_FAST_MATH_FLAGS),
 }
 
-dtype_to_llvm_dtype = {dtypes.float64:ir.DoubleType(), dtypes.float16:ir.HalfType(), dtypes.bfloat16:ir.IntType(16), dtypes.float32:ir.FloatType(), dtypes.int8:ir.IntType(8), dtypes.uint8:ir.IntType(8), dtypes.bool: ir.IntType(1), dtypes.int64: ir.IntType(64), dtypes.int32: ir.IntType(32), dtypes._arg_int32: ir.IntType(32)}
+dtype_to_llvm_dtype = {dtypes.float64:ir.DoubleType(), dtypes.float16:ir.HalfType(), dtypes.bfloat16:ir.IntType(16), dtypes.float32:ir.FloatType(), dtypes.int8:ir.IntType(8), dtypes.uint8:ir.IntType(8), dtypes.bool: ir.IntType(1), dtypes.int64: ir.IntType(64), dtypes.int32: ir.IntType(32), dtypes._arg_int32: ir.IntType(32), dtypes.int16:ir.IntType(16), dtypes.uint16:ir.IntType(16), dtypes.uint32:ir.IntType(32), dtypes.uint64:ir.IntType(64)}
 
 def cast(bb, val, input_type, output_type):
   if input_type == output_type: return val
diff --git a/tinygrad/renderer/triton.py b/tinygrad/renderer/triton.py
index 4088552e..2153131b 100644
--- a/tinygrad/renderer/triton.py
+++ b/tinygrad/renderer/triton.py
@@ -8,8 +8,8 @@ import linecache
 import math
 import re
 
-triton_dtypes = {dtypes.double: "tl.float64", dtypes.float32: "tl.float32", dtypes.float16: "tl.float16", dtypes.bool: "tl.int1", dtypes.int8: "tl.int8", dtypes.uint8: "tl.uint8", dtypes.int32: "tl.int32", dtypes.int64: "tl.int64", dtypes.uint32: "tl.uint32", dtypes.uint64: "tl.uint64"}
-signature_dtypes = {dtypes.double: "*fp64",dtypes.float32: "*fp32", dtypes.float16: "*fp16", dtypes.bool: "*i8", dtypes.int8: "*i1", dtypes.uint8: "*u8", dtypes._arg_int32: "i32", dtypes.int32: "*i32", dtypes.int64: "*i64", dtypes.uint32: "*u32", dtypes.uint64: "*u64"}
+triton_dtypes = {dtypes.double: "tl.float64", dtypes.float32: "tl.float32", dtypes.float16: "tl.float16", dtypes.bool: "tl.int1", dtypes.int8: "tl.int8", dtypes.uint8: "tl.uint8", dtypes.int32: "tl.int32", dtypes.int64: "tl.int64", dtypes.uint32: "tl.uint32", dtypes.uint64: "tl.uint64", dtypes.int16: "tl.int16", dtypes.uint16: "tl.uint16"}
+signature_dtypes = {dtypes.double: "*fp64",dtypes.float32: "*fp32", dtypes.float16: "*fp16", dtypes.bool: "*i8", dtypes.int8: "*i1", dtypes.uint8: "*u8", dtypes._arg_int32: "i32", dtypes.int32: "*i32", dtypes.int64: "*i64", dtypes.uint32: "*u32", dtypes.uint64: "*u64", dtypes.int16: "*i16", dtypes.uint16: "*u16"}
 
 def next_power_of_2(x):
   return 1 << (x - 1).bit_length()
diff --git a/tinygrad/runtime/lib.py b/tinygrad/runtime/lib.py
index b3d33a78..15a3f2ec 100644
--- a/tinygrad/runtime/lib.py
+++ b/tinygrad/runtime/lib.py
@@ -43,7 +43,7 @@ class RawBufferMapped(RawBufferCopyIn):
 
 # this one is simple enough that i moved it out of the runtimes
 class RawMallocBuffer(RawBufferMapped):
-  def __init__(self, size, dtype: DType): super().__init__(size, dtype, ({dtypes.float64:ctypes.c_double, dtypes.float32: ctypes.c_float, dtypes.float16: ctypes.c_int16, dtypes.bfloat16: ctypes.c_int16, dtypes.int8: ctypes.c_int8, dtypes.uint8: ctypes.c_uint8, dtypes.bool: ctypes.c_uint8, dtypes.int32: ctypes.c_int32, dtypes.uint32: ctypes.c_uint32, dtypes.int64: ctypes.c_int64, dtypes.uint64: ctypes.c_uint64}[dtype] * size)())
+  def __init__(self, size, dtype: DType): super().__init__(size, dtype, ({dtypes.float64:ctypes.c_double, dtypes.float32: ctypes.c_float, dtypes.float16: ctypes.c_int16, dtypes.bfloat16: ctypes.c_int16, dtypes.int8: ctypes.c_int8, dtypes.uint8: ctypes.c_uint8, dtypes.bool: ctypes.c_uint8, dtypes.int32: ctypes.c_int32, dtypes.uint32: ctypes.c_uint32, dtypes.int64: ctypes.c_int64, dtypes.uint64: ctypes.c_uint64, dtypes.int16: ctypes.c_int16, dtypes.uint16: ctypes.c_uint16}[dtype] * size)())
   def _buffer(self): return memoryview(self._buf)
 
 class RawBufferCopyInOut(RawBufferCopyIn):
diff --git a/tinygrad/runtime/ops_clang.py b/tinygrad/runtime/ops_clang.py
index 5c4fb1bd..3e82b220 100644
--- a/tinygrad/runtime/ops_clang.py
+++ b/tinygrad/runtime/ops_clang.py
@@ -18,7 +18,7 @@ args = {
   'Darwin': {'cflags':'-lm -fPIC --rtlib=compiler-rt ', 'ext':'dylib', 'exp':''}
 }[platform.system()]
 
-CLANG_PROGRAM_HEADER = '#include <math.h>\n#define max(x,y) ((x>y)?x:y)\n#define int64 long\n#define half __fp16\n#define uchar unsigned char\n#define bool uchar\n'
+CLANG_PROGRAM_HEADER = '#include <math.h>\n#define max(x,y) ((x>y)?x:y)\n#define int64 long\n#define half __fp16\n#define uchar unsigned char\n#include <stdbool.h>\n'
 ADDRESS = 0x10000
 
 # Unicorn doesn't support external calls