mirror of
https://github.com/KrisKennaway/ii-vision.git
synced 2025-07-23 13:24:31 +00:00
Update comments and fix some bugs
make_edit_distance - use MASKED_DOTS since it does not have a simple relationship to the HEADER_BITS/BODY_BITS for HGR - try disabling transposition distances for Damerau-Levenshtein, this may give better quality screen - introduce separate notion of MASKED_DOTS which is the number of (coloured) pixels we can extract from MASKED_BITS. For HGR this is not the same. - fix bug in _fix_array_neighbours that was not fixing headers for HGR - don't cache everything in byte_pair_differences, it's effectively unbounded. Using 1M for LRU size seems to work just as well in practise, without leaking memory. - fix bug in _diff_weights when comparing content, we want to evaluate the effect of storing content byte in each offset separately, not cumulatively. - add a consistency check function (not currently wired up) to assert that headers/footers are in sync across columns - HGR should have 16 body bits, this was causing headers not to propagate correctly to/from neighbouring column - add test case for this bug video - Use 8 random bits consistently, using 16 in some places may have introduced bias - ignore palette bit when comparing 0x00 and 0x7f in sanity check
This commit is contained in:
@@ -14,7 +14,7 @@ IntOrArray = Union[np.uint64, np.ndarray]
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def y_to_base_addr(y: int, page: int = 0) -> int:
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"""Maps y coordinate to base address on given screen page"""
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"""Maps y coordinate to base address on given screen page."""
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a = y // 64
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d = y - 64 * a
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b = d // 8
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@@ -126,33 +126,44 @@ class MemoryMap:
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class Bitmap:
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"""Packed 28-bit bitmap representation of (D)HGR screen memory.
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"""Packed bitmap representation of (D)HGR screen memory.
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XXX comments
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The memory layout is still page-oriented, not linear y-x buffer but the
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bit map is such that 20 consecutive entries linearly encode the 28*20 =
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560-bit monochrome dot positions that underlie both Mono and Colour (
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D)HGR screens.
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For Colour display the (nominal) colours are encoded as 4-bit pixels.
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Maintains a page-based array whose entries contain a packed representation
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of multiple screen bytes, in a representation that supports efficiently
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determining the visual effect of storing bytes at arbitrary screen offsets.
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"""
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# NOTE: See https://github.com/numpy/numpy/issues/2524 and related issues
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# for why we have to cast things explicitly to np.uint64 - type promotion
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# to uint64 is broken in numpy :(
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# Name of bitmap type
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NAME = None # type: str
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# Size of packed representation
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# Size of packed representation, consisting of header + body + footer
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HEADER_BITS = None # type: np.uint64
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BODY_BITS = None # type: np.uint64
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FOOTER_BITS = None # type: np.uint64
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# How many bits of packed representation are necessary to determine the
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# effect of storing a memory byte, e.g. because they influence pixel
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# colour or are influenced by other bits.
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MASKED_BITS = None # type: np.uint64
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# How many coloured screen pixels we can extract from MASKED_BITS. Note
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# that this does not include the last 3 dots represented by the footer,
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# since we don't have enough information to determine their colour (we
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# would fall off the end of the 4-bit sliding window)
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MASKED_DOTS = None # type: np.uint64
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# List of bitmasks for extracting the subset of packed data corresponding
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# to bits influencing/influenced by a given byte offset. These must be
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# a contiguous bit mask, i.e. so that after shifting they are enumerated
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# by 0..2**MASKED_BITS-1
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BYTE_MASKS = None # type: List[np.uint64]
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BYTE_SHIFTS = None # type: List[np.uint64]
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# How many bits of packed representation are influenced when storing a
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# memory byte
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MASKED_BITS = None # type: np.uint64
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# XXX
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# NTSC clock phase at first masked bit
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PHASES = None # type: List[int]
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def __init__(
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@@ -176,18 +187,21 @@ class Bitmap:
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shape=(32, 128), dtype=np.uint64) # type: np.ndarray
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self._pack()
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def _body(self) -> np.ndarray:
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raise NotImplementedError
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# TODO: don't leak headers/footers across screen rows. We should be using
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# x-y representation rather than page-offset
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@staticmethod
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def _make_header(prev_col: IntOrArray) -> IntOrArray:
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def _make_header(col: IntOrArray) -> IntOrArray:
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"""Extract values to use as header of next column."""
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raise NotImplementedError
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def _body(self) -> np.ndarray:
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"""Pack related screen bytes into an efficient representation."""
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raise NotImplementedError
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@staticmethod
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def _make_footer(next_col: IntOrArray) -> IntOrArray:
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def _make_footer(col: IntOrArray) -> IntOrArray:
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"""Extract values to use as footer of previous column."""
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raise NotImplementedError
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def _pack(self) -> None:
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@@ -195,17 +209,15 @@ class Bitmap:
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body = self._body()
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# XXX comments
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# Prepend last 3 bits of previous main odd byte so we can correctly
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# decode the effective colours at the beginning of the 28-bit
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# tuple
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# Prepend last 3 bits of previous odd byte so we can correctly
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# decode the effective colours at the beginning of the 22-bit tuple
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prev_col = np.roll(body, 1, axis=1).astype(np.uint64)
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header = self._make_header(prev_col)
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# Don't leak header across page boundaries
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header[:, 0] = 0
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# Append first 3 bits of next aux even byte so we can correctly
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# decode the effective colours at the end of the 28-bit tuple
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# Append first 3 bits of next even byte so we can correctly
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# decode the effective colours at the end of the 22-bit tuple
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next_col = np.roll(body, -1, axis=1).astype(np.uint64)
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footer = self._make_footer(next_col)
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# Don't leak footer across page boundaries
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@@ -218,20 +230,27 @@ class Bitmap:
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byte_offset: int,
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old_value: IntOrArray,
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new_value: np.uint8) -> IntOrArray:
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"""Update int/array to store new value at byte_offset in every entry.
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Does not patch up headers/footers of neighbouring columns.
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"""
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raise NotImplementedError
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@staticmethod
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@functools.lru_cache(None)
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def byte_offset(x_byte: int, is_aux: bool) -> int:
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def byte_offset(page_offset: int, is_aux: bool) -> int:
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"""Map screen offset for aux/main into offset within packed data."""
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raise NotImplementedError
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@staticmethod
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@functools.lru_cache(None)
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def _byte_offsets(is_aux: bool) -> Tuple[int, int]:
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"""Return byte offsets within packed data for AUX/MAIN memory."""
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raise NotImplementedError
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@classmethod
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def to_dots(cls, masked_val: int, byte_offset: int) -> int:
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"""Convert masked representation to bit sequence of display dots."""
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raise NotImplementedError
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def apply(
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@@ -254,6 +273,7 @@ class Bitmap:
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page: int,
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offset: int,
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byte_offset: int) -> None:
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"""Fix up column headers/footers when updating a (page, offset)."""
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if byte_offset == 0 and offset > 0:
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self.packed[page, offset - 1] = self._fix_column_left(
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@@ -272,6 +292,8 @@ class Bitmap:
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column_left: IntOrArray,
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column: IntOrArray
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) -> IntOrArray:
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"""Patch up the footer of the column to the left."""
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# Mask out footer(s)
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column_left &= np.uint64(2 ** (self.HEADER_BITS + self.BODY_BITS) - 1)
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column_left ^= self._make_footer(column)
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@@ -283,6 +305,8 @@ class Bitmap:
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column_right: IntOrArray,
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column: IntOrArray
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) -> IntOrArray:
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"""Patch up the header of the column to the right."""
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# Mask out header(s)
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column_right &= np.uint64(
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(2 ** (self.BODY_BITS + self.FOOTER_BITS) - 1)) << self.HEADER_BITS
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@@ -295,15 +319,19 @@ class Bitmap:
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ary: np.ndarray,
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byte_offset: int
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) -> None:
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"""Fix up column headers/footers for all array entries."""
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# TODO: don't leak header/footer across page boundaries
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# Propagate new value into neighbouring byte headers/footers if
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# necessary
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if byte_offset == 0:
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# Need to also update the 3-bit footer of the preceding column
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# Need to also update the footer of the preceding column
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shifted_left = np.roll(ary, -1, axis=1)
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self._fix_column_left(ary, shifted_left)
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elif byte_offset == 3:
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# Need to also update the 3-bit header of the next column
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elif byte_offset == (self.SCREEN_BYTES - 1):
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# Need to also update the header of the next column
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shifted_right = np.roll(ary, 1, axis=1)
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self._fix_column_right(ary, shifted_right)
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@@ -340,22 +368,25 @@ class Bitmap:
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cls,
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data: IntOrArray,
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byte_offset: int) -> IntOrArray:
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"""Masks and shifts data into the MASKED_BITS range."""
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"""Masks and shifts packed data into the MASKED_BITS range."""
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res = (data & cls.BYTE_MASKS[byte_offset]) >> (
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cls.BYTE_SHIFTS[byte_offset])
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assert np.all(res <= 2 ** cls.MASKED_BITS)
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return res
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# Can't cache all possible values but this seems to give a good enough hit
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# rate without costing too much memory
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# TODO: unit tests
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@functools.lru_cache(None)
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@functools.lru_cache(10 ** 6)
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def byte_pair_difference(
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self,
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byte_offset: int,
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old_packed: np.uint64,
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content: np.uint8
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) -> np.uint16:
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old_pixels = self.mask_and_shift_data(
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old_packed, byte_offset)
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"""Compute effect of storing a new content byte within packed data."""
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old_pixels = self.mask_and_shift_data(old_packed, byte_offset)
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new_pixels = self.mask_and_shift_data(
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self.masked_update(byte_offset, old_packed, content), byte_offset)
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@@ -368,15 +399,24 @@ class Bitmap:
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source: "Bitmap",
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is_aux: bool
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) -> np.ndarray:
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"""Compute edit distance matrix from source bitmap."""
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return self._diff_weights(source.packed, is_aux)
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# TODO: unit test
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def _diff_weights(
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self,
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source_packed: np.ndarray,
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is_aux: bool,
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content: np.uint8 = None
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) -> np.ndarray:
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"""Computes diff from source_packed to self.packed"""
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"""Computes edit distance matrix from source_packed to self.packed
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If content is set, the distance will be computed as if this value
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was stored into each offset position of source_packed, i.e. to
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allow evaluating which offsets (if any) should be chosen for storing
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this content byte.
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"""
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diff = np.ndarray((32, 256), dtype=np.int)
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offsets = self._byte_offsets(is_aux)
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@@ -384,63 +424,173 @@ class Bitmap:
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dists = []
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for o in offsets:
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if content is not None:
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source_packed = self.masked_update(o, source_packed, content)
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self._fix_array_neighbours(source_packed, o)
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compare_packed = self.masked_update(o, source_packed, content)
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self._fix_array_neighbours(compare_packed, o)
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else:
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compare_packed = source_packed
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# Pixels influenced by byte offset o
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source_pixels = self.mask_and_shift_data(source_packed, o)
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source_pixels = self.mask_and_shift_data(compare_packed, o)
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target_pixels = self.mask_and_shift_data(self.packed, o)
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# Concatenate 13-bit source and target into 26-bit values
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# Concatenate N-bit source and target into 2N-bit values
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pair = (source_pixels << self.MASKED_BITS) + target_pixels
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dist = self.edit_distances(self.palette)[o][pair].reshape(
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pair.shape)
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dists.append(dist)
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# Interleave even/odd columns
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diff[:, 0::2] = dists[0]
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diff[:, 1::2] = dists[1]
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return diff
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def _check_consistency(self):
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"""Sanity check that headers and footers are consistent."""
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headers = np.roll(self._make_header(self.packed), 1, axis=1).astype(
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np.uint64)
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footers = np.roll(self._make_footer(self.packed), -1, axis=1).astype(
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np.uint64)
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mask_hf = np.uint64(0b1110000000000000000000000000000111)
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res = (self.packed ^ headers ^ footers) & mask_hf
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nz = np.transpose(np.nonzero(res))
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ok = True
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if nz.size != 0:
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for p, o in nz.tolist():
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if o == 0 or o == 127:
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continue
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ok = False
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print(p, o, bin(self.packed[p, o - 1]),
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bin(headers[p, o]),
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bin(self.packed[p, o]),
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bin(self.packed[p, o + 1]), bin(footers[p, o]),
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bin(res[p, o])
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)
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assert ok
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# TODO: unit tests
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def compute_delta(
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self,
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content: int,
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old: np.ndarray,
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diff_weights: np.ndarray,
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is_aux: bool
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) -> np.ndarray:
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# TODO: use error edit distance
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"""Compute which content stores introduce the least additional error.
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diff = self._diff_weights(self.packed, is_aux, content)
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We compute the effect of storing content at all possible offsets
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within self.packed, and then subtract the previous diff weights.
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Negative values indicate that the new content value is closer to the
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target than the current content.
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"""
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# TODO: use error edit distance?
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new_diff = self._diff_weights(self.packed, is_aux, content)
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# TODO: try different weightings
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return (diff * 5) - old
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return (new_diff * 5) - diff_weights
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class HGRBitmap(Bitmap):
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"""Packed bitmap representation of HGR screen memory.
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The HGR display is encoded in a somewhat complicated way, so we have to
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do a bit of work to turn it into a useful format.
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Each screen byte consists of a palette bit (7) and 6 data bits (0..6)
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Each non-palette bit turns on two consecutive display dots, with bit 6
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repeated a third time. This third dot may or may not be overwritten by the
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effect of the next byte.
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Turning on the palette bit shifts that byte's dots right by one
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position.
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Given two neighbouring screen bytes Aaaaaaaa, Bbbbbbbb (at even and odd
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offsets), where capital letter indicates the position of the palette bit,
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we use the following 22-bit packed representation:
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2211111111110000000000 <-- bit position in uint22
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1098765432109876543210
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ffFbbbbbbbBAaaaaaaaHhh
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h and f are headers/footers derived from the neighbouring screen bytes.
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Since our colour artifact model (see colours.py) uses a sliding 4-bit window
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onto the dot string, we need to also include a 3-bit header and footer
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to account for the influence from/on neighbouring bytes, i.e. adjacent
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packed values. These are just the low/high 2 data bits of the 16-bit
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body of those neighbouring columns, plus the corresponding palette bit.
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This 22-bit packed representation is sufficient to compute the effects
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(on pixel colours) of storing a byte at even or odd offsets. From it we
|
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can extract the bit stream of displayed HGR dots, and the mapping to pixel
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colours follows the HGRColours bitmap, see colours.py.
|
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We put the two A/B palette bits next to each other so that we can
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mask a contiguous range of bits whose colours influence/are influenced by
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storing a byte at a given offset.
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|
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We need to mask out bit subsequences of size 3+8+3=14, i.e. the 8-bits
|
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corresponding to the byte being stored, plus the neighbouring 3 bits that
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influence it/are influenced by it.
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|
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Note that the masked representation has the same size for both offsets (
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14 bits), but different meaning, since the palette bit is in a different
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position.
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|
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With this masked representation, we can precompute an edit distance for the
|
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pixel changes resulting from all possible HGR byte stores, see
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make_edit_distance.py.
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|
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The edit distance matrix is encoded by concatenating the 14-bit source
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and target masked values into a 28-bit pair, which indexes into the
|
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edit_distance array to give the corresponding edit distance.
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"""
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NAME = 'HGR'
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|
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# hhhbbbbbbbpPBBBBBBBfff
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# 0000000011111111111111
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# 1111111111111100000000
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# Size of packed representation, consisting of header + body + footer
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HEADER_BITS = np.uint64(3)
|
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# 2x 8-bit screen bytes
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BODY_BITS = np.uint64(16)
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FOOTER_BITS = np.uint64(3)
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|
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# Header:
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# 0000000010000011
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# Footer:
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# 1100000100000000
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# How many bits of packed representation are necessary to determine the
|
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# effect of storing a memory byte, e.g. because they influence pixel
|
||||
# colour or are influenced by other bits.
|
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MASKED_BITS = np.uint64(14) # 3 + 8 + 3
|
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|
||||
# How many coloured screen pixels we can extract from MASKED_BITS. Note
|
||||
# that this does not include the last 3 dots represented by the footer,
|
||||
# since we don't have enough information to determine their colour (we
|
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# would fall off the end of the 4-bit sliding window)
|
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#
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# From header: 3 bits (2 HGR pixels but might be shifted right by palette)
|
||||
# From body: 7 bits doubled, plus possible shift from palette bit
|
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MASKED_DOTS = np.uint64(18) # 3 + 7 + 7
|
||||
|
||||
# List of bitmasks for extracting the subset of packed data corresponding
|
||||
# to bits influencing/influenced by a given byte offset. These must be
|
||||
# a contiguous bit mask, i.e. so that after shifting they are enumerated
|
||||
# by 0..2**MASKED_BITS-1
|
||||
BYTE_MASKS = [
|
||||
np.uint64(0b0000000011111111111111),
|
||||
np.uint64(0b1111111111111100000000)
|
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]
|
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BYTE_SHIFTS = [np.uint64(0), np.uint64(8)]
|
||||
MASKED_BITS = np.uint64(14) # 3 + 8 + 3
|
||||
|
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HEADER_BITS = np.uint64(3)
|
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# 7-bits doubled, plus possible shift from palette bit
|
||||
BODY_BITS = np.uint64(15)
|
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FOOTER_BITS = np.uint64(3)
|
||||
|
||||
# NTSC clock phase at first masked bit
|
||||
#
|
||||
# Each HGR byte offset has the same range of uint14 possible
|
||||
# values and nominal colour pixels, but with different initial
|
||||
# phases:
|
||||
# even: 0 (1 at start of 3-bit header)
|
||||
# odd: 2 (3)
|
||||
PHASES = [1, 3]
|
||||
|
||||
def __init__(self, palette: pal.Palette, main_memory: MemoryMap):
|
||||
@@ -448,10 +598,11 @@ class HGRBitmap(Bitmap):
|
||||
|
||||
@staticmethod
|
||||
def _make_header(col: IntOrArray) -> IntOrArray:
|
||||
# Header format is bits 5,6,0 of previous byte
|
||||
# i.e. offsets 16, 17, 11
|
||||
"""Extract values to use as header of next column.
|
||||
|
||||
# return (col & np.uint64(0b111 << 16)) >> np.uint64(16)
|
||||
Header format is bits 5,6,0 of previous screen byte
|
||||
i.e. offsets 17, 18, 11 in packed representation
|
||||
"""
|
||||
|
||||
return (
|
||||
(col & np.uint64(0b1 << 11)) >> np.uint64(9) ^ (
|
||||
@@ -459,11 +610,13 @@ class HGRBitmap(Bitmap):
|
||||
)
|
||||
|
||||
def _body(self) -> np.ndarray:
|
||||
# Body is in order
|
||||
# a0 a1 a2 a3 a4 a5 a6 a7 b7 b0 b1 b2 b3 b4 b5 b6
|
||||
# so that a) the header and footer have the same order
|
||||
# across the two byte offsets, and b) so that they
|
||||
# can be extracted as contiguous bit ranges
|
||||
"""Pack related screen bytes into an efficient representation.
|
||||
|
||||
Body is of the form:
|
||||
bbbbbbbBAaaaaaaa
|
||||
|
||||
where capital indicates the palette bit.
|
||||
"""
|
||||
|
||||
even = self.main_memory.page_offset[:, 0::2].astype(np.uint64)
|
||||
odd = self.main_memory.page_offset[:, 1::2].astype(np.uint64)
|
||||
@@ -474,133 +627,46 @@ class HGRBitmap(Bitmap):
|
||||
|
||||
@staticmethod
|
||||
def _make_footer(col: IntOrArray) -> IntOrArray:
|
||||
# Footer format is bits 7,0,1 of next byte
|
||||
# i.e. offsets 10,3,4
|
||||
"""Extract values to use as footer of previous column.
|
||||
|
||||
Footer format is bits 7,0,1 of next screen byte
|
||||
i.e. offsets 10,3,4 in packed representation
|
||||
"""
|
||||
|
||||
return (
|
||||
(col & np.uint64(0b1 << 10)) >> np.uint64(10) ^ (
|
||||
(col & np.uint64(0b11 << 3)) >> np.uint64(2))
|
||||
) << np.uint64(19)
|
||||
|
||||
# # XXX move to make_data_tables
|
||||
# def _pack(self) -> None:
|
||||
# """Pack main memory into (28+3)-bit uint64 array"""
|
||||
#
|
||||
# # 00000000001111111111222222222233
|
||||
# # 01234567890123456789012345678901
|
||||
# # AAAABBBBCCCCDDd
|
||||
# # AAAABBBBCCCCDd
|
||||
# # DDEEEEFFFFGGGGg
|
||||
# # dDDEEEEFFFFGGGg
|
||||
#
|
||||
# # Even, P0: store unshifted (0..14)
|
||||
# # Even, P1: store shifted << 1 (1..15) (only need 1..14)
|
||||
#
|
||||
# # Odd, P0: store shifted << 14 (14 .. 28) - set bit 14 as bit 0 of next
|
||||
# # byte
|
||||
# # Odd, p1: store shifted << 15 (15 .. 29) (only need 15 .. 28) - set
|
||||
# # bit 13 as bit 0 of next byte
|
||||
#
|
||||
# # Odd overflow only matters for even, P1
|
||||
# # - bit 0 is either bit 14 if odd, P0 or bit 13 if odd, P1
|
||||
# # - but these both come from the undoubled bit 6.
|
||||
#
|
||||
# main = self.main_memory.page_offset.astype(np.uint64)
|
||||
#
|
||||
# # Double 7-bit pixel data from a into 14-bit fat pixels, and extend MSB
|
||||
# # into 15-bits tohandle case when subsequent byte has palette bit set,
|
||||
# # i.e. is right-shifted by 1 dot. This only matters for even bytes
|
||||
# # with P=0 that are followed by odd bytes with P=1; in other cases
|
||||
# # this extra bit will be overwritten.
|
||||
# double = (
|
||||
# # Bit pos 6
|
||||
# ((main & 0x40) << 8) + ((main & 0x40) << 7) + (
|
||||
# (main & 0x40) << 6)) + (
|
||||
# # Bit pos 5
|
||||
# ((main & 0x20) << 6) + ((main & 0x20) << 5)) + (
|
||||
# # Bit pos 4
|
||||
# ((main & 0x10) << 5) + ((main & 0x10) << 4)) + (
|
||||
# # Bit pos 3
|
||||
# ((main & 0x08) << 4) + ((main & 0x08) << 3)) + (
|
||||
# # Bit pos 2
|
||||
# ((main & 0x04) << 3) + ((main & 0x04) << 2)) + (
|
||||
# # Bit pos 1
|
||||
# ((main & 0x02) << 2) + ((main & 0x02) << 1)) + (
|
||||
# # Bit pos 0
|
||||
# ((main & 0x01) << 1) + (main & 0x01))
|
||||
#
|
||||
# a_even = main[:, ::2]
|
||||
# a_odd = main[:, 1::2]
|
||||
#
|
||||
# double_even = double[:, ::2]
|
||||
# double_odd = double[:, 1::2]
|
||||
#
|
||||
# # Place even offsets at bits 1..15 (P=1) or 0..14 (P=0)
|
||||
# packed = np.where(a_even & 0x80, double_even << 1, double_even)
|
||||
#
|
||||
# # Place off offsets at bits 15..27 (P=1) or 14..27 (P=0)
|
||||
# packed = np.where(
|
||||
# a_odd & 0x80,
|
||||
# np.bitwise_xor(
|
||||
# np.bitwise_and(packed, (2 ** 15 - 1)),
|
||||
# double_odd << 15
|
||||
# ),
|
||||
# np.bitwise_xor(
|
||||
# np.bitwise_and(packed, (2 ** 14 - 1)),
|
||||
# double_odd << 14
|
||||
# )
|
||||
# )
|
||||
#
|
||||
# # Patch up even offsets with P=1 with extended bit from previous odd
|
||||
# # column
|
||||
#
|
||||
# previous_odd = np.roll(a_odd, 1, axis=1).astype(np.uint64)
|
||||
#
|
||||
# packed = np.where(
|
||||
# a_even & 0x80,
|
||||
# # Truncate to 28-bits and set bit 0 from bit 6 of previous byte
|
||||
# np.bitwise_xor(
|
||||
# np.bitwise_and(packed, (2 ** 28 - 2)),
|
||||
# (previous_odd & (1 << 6)) >> 6
|
||||
# ),
|
||||
# # Truncate to 28-bits
|
||||
# np.bitwise_and(packed, (2 ** 28 - 1))
|
||||
# )
|
||||
#
|
||||
# # Append first 3 bits of next even byte so we can correctly
|
||||
# # decode the effective colours at the end of the 28-bit tuple
|
||||
# trailing = np.roll(packed, -1, axis=1).astype(np.uint64)
|
||||
#
|
||||
# packed = np.bitwise_xor(
|
||||
# packed,
|
||||
# (trailing & 0b111) << 28
|
||||
# )
|
||||
#
|
||||
# self.packed = packed
|
||||
|
||||
@staticmethod
|
||||
@functools.lru_cache(None)
|
||||
def byte_offset(x_byte: int, is_aux: bool) -> int:
|
||||
"""Returns 0..1 offset in packed representation for a given x_byte."""
|
||||
assert not is_aux
|
||||
def byte_offset(page_offset: int, is_aux: bool) -> int:
|
||||
"""Returns 0..1 offset in packed representation for page_offset."""
|
||||
|
||||
is_odd = x_byte % 2 == 1
|
||||
assert not is_aux
|
||||
is_odd = page_offset % 2 == 1
|
||||
|
||||
return 1 if is_odd else 0
|
||||
|
||||
@staticmethod
|
||||
@functools.lru_cache(None)
|
||||
def _byte_offsets(is_aux: bool) -> Tuple[int, int]:
|
||||
"""Return byte offsets within packed data for AUX/MAIN memory."""
|
||||
|
||||
assert not is_aux
|
||||
return 0, 1
|
||||
|
||||
@staticmethod
|
||||
@functools.lru_cache(None)
|
||||
def _double_pixels(int7: int) -> int:
|
||||
"""Each bit 0..6 controls two hires dots.
|
||||
|
||||
# Input bit 6 is repeated 3 times in case the neighbouring byte is
|
||||
# delayed (right-shifted by one dot) due to the palette bit being set.
|
||||
# Care needs to be taken to mask this out when overwriting.
|
||||
Input bit 6 is repeated 3 times in case the neighbouring byte is
|
||||
delayed (right-shifted by one dot) due to the palette bit being set,
|
||||
which means the effect of this byte is "extended" by an extra dot.
|
||||
|
||||
Care needs to be taken to mask this out when overwriting.
|
||||
"""
|
||||
double = (
|
||||
# Bit pos 6
|
||||
((int7 & 0x40) << 8) + ((int7 & 0x40) << 7) + (
|
||||
@@ -608,32 +674,38 @@ class HGRBitmap(Bitmap):
|
||||
# Bit pos 5
|
||||
((int7 & 0x20) << 6) + ((int7 & 0x20) << 5) +
|
||||
# Bit pos 4
|
||||
((int7 & 0x10) << 5) + ((int7 & 0x10) << 4) + (
|
||||
# Bit pos 3
|
||||
((int7 & 0x08) << 4) + ((int7 & 0x08) << 3) +
|
||||
# Bit pos 2
|
||||
((int7 & 0x04) << 3) + ((int7 & 0x04) << 2) +
|
||||
# Bit pos 1
|
||||
((int7 & 0x02) << 2) + ((int7 & 0x02) << 1) +
|
||||
# Bit pos 0
|
||||
((int7 & 0x01) << 1) + (int7 & 0x01))
|
||||
((int7 & 0x10) << 5) + ((int7 & 0x10) << 4) +
|
||||
# Bit pos 3
|
||||
((int7 & 0x08) << 4) + ((int7 & 0x08) << 3) +
|
||||
# Bit pos 2
|
||||
((int7 & 0x04) << 3) + ((int7 & 0x04) << 2) +
|
||||
# Bit pos 1
|
||||
((int7 & 0x02) << 2) + ((int7 & 0x02) << 1) +
|
||||
# Bit pos 0
|
||||
((int7 & 0x01) << 1) + (int7 & 0x01)
|
||||
)
|
||||
|
||||
return double
|
||||
|
||||
@classmethod
|
||||
def to_dots(cls, masked_val: int, byte_offset: int) -> int:
|
||||
"""Convert masked representation to bit sequence of display dots.
|
||||
|
||||
Packed representation is of the form:
|
||||
ffFbbbbbbbBAaaaaaaaHhh
|
||||
|
||||
where capital indicates the palette bit.
|
||||
|
||||
Each non-palette bit turns on two display dots, with bit 6 repeated
|
||||
a third time. This may or may not be overwritten by the next byte.
|
||||
|
||||
Turning on the palette bit shifts that byte's dots right by one
|
||||
position.
|
||||
"""
|
||||
|
||||
# Assert 14-bit representation
|
||||
assert (masked_val & (2 ** 14 - 1)) == masked_val
|
||||
|
||||
# Unpack hhHaaaaaaaABbbbbbbbFff
|
||||
|
||||
# --> hhhaaaaaaaaaaaaaabbbb (P=0, P=0, P=0)
|
||||
# hhhaaaaaaaaaaaaaabbbb (P=1, P=0, P=0)
|
||||
# hhhhaaaaaaaaaaaaabbbb (P=1, P=1, P=0)
|
||||
# hhhhaaaaaaaaaaaaaabbb (P=1, P=1, P=1)
|
||||
|
||||
# Take top 3 bits from header (plus duplicated MSB) not 4, because if it
|
||||
# is palette-shifted then we don't know what is in bit 0
|
||||
h = (masked_val & 0b111) << 5
|
||||
@@ -641,11 +713,11 @@ class HGRBitmap(Bitmap):
|
||||
res = cls._double_pixels(h & 0x7f) >> (11 - hp)
|
||||
|
||||
if byte_offset == 0:
|
||||
# Offset 0: hhHaaaaaaaABbb
|
||||
# Offset 0: bbBAaaaaaaaHhh
|
||||
b = (masked_val >> 3) & 0xff
|
||||
bp = (b & 0x80) >> 7
|
||||
else:
|
||||
# Offset 1: aaABbbbbbbbFff
|
||||
# Offset 1: ffFbbbbbbbBAaa
|
||||
bp = (masked_val >> 3) & 0x01
|
||||
b = ((masked_val >> 4) & 0x7f) ^ (bp << 7)
|
||||
|
||||
@@ -664,7 +736,6 @@ class HGRBitmap(Bitmap):
|
||||
res ^= cls._double_pixels(f & 0x7f) << (17 + fp)
|
||||
return res & (2 ** 21 - 1)
|
||||
|
||||
# XXX test
|
||||
@staticmethod
|
||||
def masked_update(
|
||||
byte_offset: int,
|
||||
@@ -694,37 +765,99 @@ class HGRBitmap(Bitmap):
|
||||
|
||||
|
||||
class DHGRBitmap(Bitmap):
|
||||
# NOTE: See https://github.com/numpy/numpy/issues/2524 and related issues
|
||||
# for why we have to cast things explicitly to np.uint64 - type promotion
|
||||
# to uint64 is broken in numpy :(
|
||||
"""Packed bitmap representation of DHGR screen memory.
|
||||
|
||||
The DHGR display encodes 7 pixels across interleaved 4-byte sequences
|
||||
of AUX and MAIN memory, as follows:
|
||||
|
||||
PBBBAAAA PDDCCCCB PFEEEEDD PGGGGFFF
|
||||
Aux N Main N Aux N+1 Main N+1 (N even)
|
||||
|
||||
Where A..G are the pixels, and P represents the (unused) palette bit.
|
||||
|
||||
This layout makes more sense when written as a (little-endian) 32-bit
|
||||
integer:
|
||||
|
||||
33222222222211111111110000000000 <- bit pos in uint32
|
||||
10987654321098765432109876543210
|
||||
PGGGGFFFPFEEEEDDPDDCCCCBPBBBAAAA
|
||||
|
||||
i.e. apart from the palette bits this is a linear ordering of pixels,
|
||||
when read from LSB to MSB (i.e. right-to-left). i.e. the screen layout
|
||||
order of bits is opposite to the usual binary representation ordering.
|
||||
|
||||
We can simplify things by stripping out the palette bit and packing
|
||||
down to a 28-bit integer representation:
|
||||
|
||||
33222222222211111111110000000000 <- bit pos in uint32
|
||||
10987654321098765432109876543210
|
||||
|
||||
GGGGFFFFEEEEDDDDCCCCBBBBAAAA <- pixel A..G
|
||||
3210321032103210321032103210 <- bit pos in A..G pixel
|
||||
|
||||
3333333222222211111110000000 <- byte offset 0.3
|
||||
|
||||
Since our colour artifact model (see colours.py) uses a sliding 4-bit window
|
||||
onto the dot string, we need to also include a 3-bit header and footer
|
||||
to account for the influence from/on neighbouring bytes, i.e. adjacent
|
||||
packed values. These are just the low/high 3 bits of the 28-bit body of
|
||||
those neighbouring columns.
|
||||
|
||||
This gives a 34-bit packed representation that is sufficient to compute
|
||||
the effects (on pixel colours) of storing a byte at one of the 0..3 offsets.
|
||||
|
||||
Note that this representation is also 1:1 with the actual displayed
|
||||
DHGR dots. The mapping to pixel colours follows the DHGRColours
|
||||
bitmap, see colours.py.
|
||||
|
||||
Because the packed representation is contiguous, we need to mask out bit
|
||||
subsequences of size 3+7+3=13, i.e. the 7-bits corresponding to the
|
||||
byte being stored, plus the neighbouring 3 bits that influence it/are
|
||||
influenced by it.
|
||||
|
||||
With this masked representation, we can precompute an edit distance for the
|
||||
pixel changes resulting from all possible DHGR byte stores, see
|
||||
make_edit_distance.py.
|
||||
|
||||
The edit distance matrix is encoded by concatenating the 13-bit source
|
||||
and target masked values into a 26-bit pair, which indexes into the
|
||||
edit_distance array to give the corresponding edit distance.
|
||||
"""
|
||||
|
||||
NAME = 'DHGR'
|
||||
|
||||
# 3-bit header + 28-bit body + 3-bit footer
|
||||
BYTE_MASKS = [
|
||||
# 3333333222222211111110000000 <- byte 0.3
|
||||
#
|
||||
# 3333222222222211111111110000000000 <- bit pos in uint64
|
||||
# 3210987654321098765432109876543210
|
||||
# tttGGGGFFFFEEEEDDDDCCCCBBBBAAAAhhh <- pixel A..G
|
||||
# 3210321032103210321032103210 <- bit pos in A..G pixel
|
||||
np.uint64(0b0000000000000000000001111111111111), # byte 0 int13 mask
|
||||
np.uint64(0b0000000000000011111111111110000000), # byte 1 int13 mask
|
||||
np.uint64(0b0000000111111111111100000000000000), # byte 2 int13 mask
|
||||
np.uint64(0b1111111111111000000000000000000000), # byte 3 int13 mask
|
||||
]
|
||||
|
||||
# How much to right-shift bits after masking to bring into int13 range
|
||||
BYTE_SHIFTS = [np.uint64(0), np.uint64(7), np.uint64(14), np.uint64(21)]
|
||||
|
||||
# Packed representation is 3 + 28 + 3 = 34 bits
|
||||
HEADER_BITS = np.uint64(3)
|
||||
BODY_BITS = np.uint64(28)
|
||||
FOOTER_BITS = np.uint64(3)
|
||||
|
||||
MASKED_BITS = np.uint64(13)
|
||||
# Masked representation selecting the influence of each byte offset
|
||||
MASKED_BITS = np.uint64(13) # 7-bit body + 3-bit header + 3-bit footer
|
||||
|
||||
# Masking is 1:1 with screen dots, but we can't compute the colour of the
|
||||
# last 3 dots because we fall off the end of the 4-bit sliding window
|
||||
MASKED_DOTS = np.uint64(10)
|
||||
|
||||
# 3-bit header + 28-bit body + 3-bit footer
|
||||
BYTE_MASKS = [
|
||||
# 3333222222222211111111110000000000 <- bit pos in uint64
|
||||
# 3210987654321098765432109876543210
|
||||
# tttGGGGFFFFEEEEDDDDCCCCBBBBAAAAhhh <- pixel A..G
|
||||
# 3210321032103210321032103210 <- bit pos in A..G pixel
|
||||
#
|
||||
# 3333333222222211111110000000 <- byte offset 0.3
|
||||
np.uint64(0b0000000000000000000001111111111111), # byte 0 uint13 mask
|
||||
np.uint64(0b0000000000000011111111111110000000), # byte 1 uint13 mask
|
||||
np.uint64(0b0000000111111111111100000000000000), # byte 2 uint13 mask
|
||||
np.uint64(0b1111111111111000000000000000000000), # byte 3 uint13 mask
|
||||
]
|
||||
|
||||
# How much to right-shift bits after masking, to bring into uint13 range
|
||||
BYTE_SHIFTS = [np.uint64(0), np.uint64(7), np.uint64(14), np.uint64(21)]
|
||||
|
||||
# NTSC clock phase at first masked bit
|
||||
# Each DHGR byte offset has the same range of int13 possible
|
||||
#
|
||||
# Each DHGR byte offset has the same range of uint13 possible
|
||||
# values and nominal colour pixels, but with different initial
|
||||
# phases:
|
||||
# AUX 0: 0 (1 at start of 3-bit header)
|
||||
@@ -733,19 +866,27 @@ class DHGRBitmap(Bitmap):
|
||||
# MAIN 1: 1 (2)
|
||||
PHASES = [1, 0, 3, 2]
|
||||
|
||||
@staticmethod
|
||||
def _make_header(col: IntOrArray) -> IntOrArray:
|
||||
"""Extract upper 3 bits of body for header of next column."""
|
||||
return (col & np.uint64(0b111 << 28)) >> np.uint64(28)
|
||||
|
||||
def _body(self) -> np.ndarray:
|
||||
"""Pack related screen bytes into an efficient representation.
|
||||
|
||||
For DHGR we first strip off the (unused) palette bit to produce
|
||||
7-bit values, then interleave aux and main memory columns and pack
|
||||
these 7-bit values into 28-bits. This sequentially encodes 7 4-bit
|
||||
DHGR pixels, which is the "repeating unit" of the DHGR screen, and
|
||||
in a form that is convenient to operate on.
|
||||
|
||||
We also shift to make room for the 3-bit header.
|
||||
"""
|
||||
|
||||
# Palette bit is unused for DHGR so mask it out
|
||||
aux = (self.aux_memory.page_offset & 0x7f).astype(np.uint64)
|
||||
main = (self.main_memory.page_offset & 0x7f).astype(np.uint64)
|
||||
|
||||
# XXX update
|
||||
# Interleave aux and main memory columns and pack 7-bit masked values
|
||||
# into a 28-bit value, with 3-bit header and footer. This
|
||||
# sequentially encodes 7 4-bit DHGR pixels, together with the
|
||||
# neighbouring 3 bits that are necessary to decode artifact colours.
|
||||
#
|
||||
# See make_data_tables.py for more discussion about this representation.
|
||||
|
||||
return (
|
||||
(aux[:, 0::2] << 3) +
|
||||
(main[:, 0::2] << 10) +
|
||||
@@ -753,11 +894,6 @@ class DHGRBitmap(Bitmap):
|
||||
(main[:, 1::2] << 24)
|
||||
)
|
||||
|
||||
@staticmethod
|
||||
def _make_header(col: IntOrArray) -> IntOrArray:
|
||||
"""Extract upper 3 bits of body for header of next column."""
|
||||
return (col & np.uint64(0b111 << 28)) >> np.uint64(28)
|
||||
|
||||
@staticmethod
|
||||
def _make_footer(col: IntOrArray) -> IntOrArray:
|
||||
"""Extract lower 3 bits of body for footer of previous column."""
|
||||
@@ -765,9 +901,10 @@ class DHGRBitmap(Bitmap):
|
||||
|
||||
@staticmethod
|
||||
@functools.lru_cache(None)
|
||||
def byte_offset(x_byte: int, is_aux: bool) -> int:
|
||||
"""Returns 0..3 packed byte offset for a given x_byte and is_aux"""
|
||||
is_odd = x_byte % 2 == 1
|
||||
def byte_offset(page_offset: int, is_aux: bool) -> int:
|
||||
"""Returns 0..3 packed byte offset for a given page_offset and is_aux"""
|
||||
|
||||
is_odd = page_offset % 2 == 1
|
||||
if is_aux:
|
||||
if is_odd:
|
||||
return 2
|
||||
@@ -781,6 +918,8 @@ class DHGRBitmap(Bitmap):
|
||||
@staticmethod
|
||||
@functools.lru_cache(None)
|
||||
def _byte_offsets(is_aux: bool) -> Tuple[int, int]:
|
||||
"""Return byte offsets within packed data for AUX/MAIN memory."""
|
||||
|
||||
if is_aux:
|
||||
offsets = (0, 2)
|
||||
else:
|
||||
@@ -790,8 +929,11 @@ class DHGRBitmap(Bitmap):
|
||||
|
||||
@classmethod
|
||||
def to_dots(cls, masked_val: int, byte_offset: int) -> int:
|
||||
# For DHGR the 13-bit masked value is already a 13-bit dot sequence
|
||||
# so no need to transform it.
|
||||
"""Convert masked representation to bit sequence of display dots.
|
||||
|
||||
For DHGR the 13-bit masked value is already a 13-bit dot sequence
|
||||
so no need to transform it.
|
||||
"""
|
||||
|
||||
return masked_val
|
||||
|
||||
@@ -804,7 +946,6 @@ class DHGRBitmap(Bitmap):
|
||||
|
||||
Does not patch up headers/footers of neighbouring columns.
|
||||
"""
|
||||
|
||||
# Mask out 7-bit value where update will go
|
||||
masked_value = old_value & (
|
||||
~np.uint64(0x7f << (7 * byte_offset + 3)))
|
||||
|
Reference in New Issue
Block a user