mirror of
https://github.com/KrisKennaway/ii-vision.git
synced 2024-12-21 20:29:21 +00:00
f3d03a1b87
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
956 lines
34 KiB
Python
956 lines
34 KiB
Python
"""Various representations of Apple II video display."""
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import bz2
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import functools
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import pickle
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from typing import Union, List, Optional, Tuple
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import numpy as np
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import palette as pal
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# Type annotation for cases where we may process either an int or a numpy array.
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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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a = y // 64
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d = y - 64 * a
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b = d // 8
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c = d - 8 * b
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addr = 8192 * (page + 1) + 1024 * c + 128 * b + 40 * a
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return addr
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Y_TO_BASE_ADDR = [
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[y_to_base_addr(y, screen_page) for y in range(192)]
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for screen_page in (0, 1)
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]
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# Array mapping (page, offset) to x (byte) and y coords respectively
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# TODO: is np.dtype(int) faster for these?
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PAGE_OFFSET_TO_X = np.zeros((32, 256), dtype=np.uint8)
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PAGE_OFFSET_TO_Y = np.zeros((32, 256), dtype=np.uint8)
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# Inverse mappings
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X_Y_TO_PAGE = np.zeros((192, 40), dtype=np.uint8)
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X_Y_TO_OFFSET = np.zeros((192, 40), dtype=np.uint8)
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# Mask of which (page, offset) bytes represent screen holes
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SCREEN_HOLES = np.full((32, 256), True, dtype=np.bool)
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# Dict mapping memory address to (page, y, x_byte) tuple
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ADDR_TO_COORDS = {}
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def _populate_mappings():
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for y in range(192):
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for x in range(40):
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y_base = Y_TO_BASE_ADDR[0][y]
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page = y_base >> 8
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offset = y_base - (page << 8) + x
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PAGE_OFFSET_TO_Y[page - 32, offset] = y
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PAGE_OFFSET_TO_X[page - 32, offset] = x
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X_Y_TO_PAGE[y, x] = page - 32
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X_Y_TO_OFFSET[y, x] = offset
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# This (page, offset) is not a screen hole
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SCREEN_HOLES[page - 32, offset] = False
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for p in range(2):
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a = Y_TO_BASE_ADDR[p][y] + x
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ADDR_TO_COORDS[a] = (p, y, x)
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_populate_mappings()
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class FlatMemoryMap:
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"""Linear 8K representation of HGR screen memory."""
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def __init__(self, screen_page: int, data: np.array = None):
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if screen_page not in [1, 2]:
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raise ValueError("Screen page out of bounds: %d" % screen_page)
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self.screen_page = screen_page # type: int
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self._addr_start = 8192 * self.screen_page
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self._addr_end = self._addr_start + 8191
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self.data = None # type: np.array
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if data is not None:
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if data.shape != (8192,):
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raise ValueError("Unexpected shape: %r" % (data.shape,))
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self.data = data
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else:
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self.data = np.zeros((8192,), dtype=np.uint8)
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def to_memory_map(self):
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return MemoryMap(self.screen_page, self.data.reshape((32, 256)))
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def write(self, addr: int, val: int) -> None:
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"""Updates screen image to set 0xaddr = val (including screen holes)"""
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if addr < self._addr_start or addr > self._addr_end:
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raise ValueError("Address out of range: 0x%04x" % addr)
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self.data[addr - self._addr_start] = val
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class MemoryMap:
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"""Page/offset-structured representation of HGR screen memory."""
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def __init__(self, screen_page: int, page_offset: np.array = None):
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if screen_page not in [1, 2]:
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raise ValueError("Screen page out of bounds: %d" % screen_page)
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self.screen_page = screen_page # type: int
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self._page_start = 32 * screen_page
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self.page_offset = None # type: np.array
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if page_offset is not None:
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if page_offset.shape != (32, 256):
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raise ValueError("Unexpected shape: %r" % (page_offset.shape,))
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self.page_offset = page_offset
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else:
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self.page_offset = np.zeros((32, 256), dtype=np.uint8)
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def to_flat_memory_map(self) -> FlatMemoryMap:
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return FlatMemoryMap(self.screen_page, self.page_offset.reshape(8192))
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def write(self, page: int, offset: int, val: int) -> None:
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"""Updates screen image to set (page, offset)=val (inc. screen holes)"""
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self.page_offset[page - self._page_start][offset] = val
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class Bitmap:
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"""Packed bitmap representation of (D)HGR screen memory.
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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, 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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# 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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self,
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palette: pal.Palette,
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main_memory: MemoryMap,
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aux_memory: Optional[MemoryMap]
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):
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self.palette = palette # type: pal.Palette
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self.main_memory = main_memory # type: MemoryMap
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self.aux_memory = aux_memory # type: Optional[MemoryMap]
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self.PACKED_BITS = (
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self.HEADER_BITS + self.BODY_BITS + self.FOOTER_BITS
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) # type: np.uint64
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# How many screen bytes we pack into a single scalar
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self.SCREEN_BYTES = np.uint64(len(self.BYTE_MASKS)) # type: np.uint64
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self.packed = np.empty(
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shape=(32, 128), dtype=np.uint64) # type: np.ndarray
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self._pack()
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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(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(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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"""Pack MemoryMap into efficient representation for diffing."""
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body = self._body()
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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 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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footer[:, -1] = 0
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self.packed = header ^ body ^ footer
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@staticmethod
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def masked_update(
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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(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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self,
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page: int,
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offset: int,
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is_aux: bool,
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value: np.uint8) -> None:
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"""Update packed representation of changing main/aux memory."""
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byte_offset = self.byte_offset(offset, is_aux)
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packed_offset = offset // 2
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self.packed[page, packed_offset] = self.masked_update(
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byte_offset, self.packed[page, packed_offset], value)
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self._fix_scalar_neighbours(page, packed_offset, byte_offset)
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def _fix_scalar_neighbours(
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self,
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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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self.packed[page, offset - 1],
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self.packed[page, offset]
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)
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elif byte_offset == (self.SCREEN_BYTES - 1) and offset < 127:
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# Need to also update the 3-bit header of the next column
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self.packed[page, offset + 1] = self._fix_column_right(
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self.packed[page, offset + 1],
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self.packed[page, offset]
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)
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def _fix_column_left(
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self,
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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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return column_left
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def _fix_column_right(
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self,
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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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column_right ^= self._make_header(column)
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return column_right
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def _fix_array_neighbours(
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self,
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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 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 == (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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@classmethod
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@functools.lru_cache(None)
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def edit_distances(cls, palette_id: pal.Palette) -> List[np.ndarray]:
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"""Load edit distance matrices for masked, shifted byte values."""
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data = "transcoder/data/%s_palette_%d_edit_distance.pickle.bz2" % (
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cls.NAME,
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palette_id.value
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)
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with bz2.open(data, "rb") as ed:
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dist = pickle.load(ed) # type: List[np.ndarray]
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# dist is an upper-triangular matrix of edit_distance(a, b)
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# encoded as dist[(a << N) + b] = edit_distance(a, b)
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# Because the distance metric is reflexive,
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# edit_distance(b, a) = edit_distance(a, b)
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identity = np.arange(2 ** (2 * cls.MASKED_BITS), dtype=np.uint64)
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# Swap values of form a << N + b to b << N + a
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transpose = (identity >> cls.MASKED_BITS) + (
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(identity & np.uint64(2 ** cls.MASKED_BITS - 1)) <<
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cls.MASKED_BITS)
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for i in range(len(dist)):
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dist[i][transpose] += dist[i][identity]
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return dist
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@classmethod
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def mask_and_shift_data(
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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 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(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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"""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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pair = (old_pixels << self.MASKED_BITS) + new_pixels
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return self.edit_distances(self.palette)[byte_offset][pair]
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def diff_weights(
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self,
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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 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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dists = []
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for o in offsets:
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if content is not None:
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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(compare_packed, o)
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target_pixels = self.mask_and_shift_data(self.packed, o)
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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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diff_weights: np.ndarray,
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is_aux: bool
|
|
) -> np.ndarray:
|
|
"""Compute which content stores introduce the least additional error.
|
|
|
|
We compute the effect of storing content at all possible offsets
|
|
within self.packed, and then subtract the previous diff weights.
|
|
|
|
Negative values indicate that the new content value is closer to the
|
|
target than the current content.
|
|
"""
|
|
# TODO: use error edit distance?
|
|
|
|
new_diff = self._diff_weights(self.packed, is_aux, content)
|
|
|
|
# TODO: try different weightings
|
|
return (new_diff * 5) - diff_weights
|
|
|
|
|
|
class HGRBitmap(Bitmap):
|
|
"""Packed bitmap representation of HGR screen memory.
|
|
|
|
The HGR display is encoded in a somewhat complicated way, so we have to
|
|
do a bit of work to turn it into a useful format.
|
|
|
|
Each screen byte consists of a palette bit (7) and 6 data bits (0..6)
|
|
|
|
Each non-palette bit turns on two consecutive display dots, with bit 6
|
|
repeated a third time. This third dot may or may not be overwritten by the
|
|
effect of the next byte.
|
|
|
|
Turning on the palette bit shifts that byte's dots right by one
|
|
position.
|
|
|
|
Given two neighbouring screen bytes Aaaaaaaa, Bbbbbbbb (at even and odd
|
|
offsets), where capital letter indicates the position of the palette bit,
|
|
we use the following 22-bit packed representation:
|
|
|
|
2211111111110000000000 <-- bit position in uint22
|
|
1098765432109876543210
|
|
ffFbbbbbbbBAaaaaaaaHhh
|
|
|
|
h and f are headers/footers derived from the neighbouring screen bytes.
|
|
|
|
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 2 data bits of the 16-bit
|
|
body of those neighbouring columns, plus the corresponding palette bit.
|
|
|
|
This 22-bit packed representation is sufficient to compute the effects
|
|
(on pixel colours) of storing a byte at even or odd offsets. From it we
|
|
can extract the bit stream of displayed HGR dots, and the mapping to pixel
|
|
colours follows the HGRColours bitmap, see colours.py.
|
|
|
|
We put the two A/B palette bits next to each other so that we can
|
|
mask a contiguous range of bits whose colours influence/are influenced by
|
|
storing a byte at a given offset.
|
|
|
|
We need to mask out bit subsequences of size 3+8+3=14, i.e. the 8-bits
|
|
corresponding to the byte being stored, plus the neighbouring 3 bits that
|
|
influence it/are influenced by it.
|
|
|
|
Note that the masked representation has the same size for both offsets (
|
|
14 bits), but different meaning, since the palette bit is in a different
|
|
position.
|
|
|
|
With this masked representation, we can precompute an edit distance for the
|
|
pixel changes resulting from all possible HGR byte stores, see
|
|
make_edit_distance.py.
|
|
|
|
The edit distance matrix is encoded by concatenating the 14-bit source
|
|
and target masked values into a 28-bit pair, which indexes into the
|
|
edit_distance array to give the corresponding edit distance.
|
|
"""
|
|
NAME = 'HGR'
|
|
|
|
# Size of packed representation, consisting of header + body + footer
|
|
HEADER_BITS = np.uint64(3)
|
|
# 2x 8-bit screen bytes
|
|
BODY_BITS = np.uint64(16)
|
|
FOOTER_BITS = np.uint64(3)
|
|
|
|
# How many bits of packed representation are necessary to determine the
|
|
# effect of storing a memory byte, e.g. because they influence pixel
|
|
# colour or are influenced by other bits.
|
|
MASKED_BITS = np.uint64(14) # 3 + 8 + 3
|
|
|
|
# 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
|
|
# would fall off the end of the 4-bit sliding window)
|
|
#
|
|
# 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
|
|
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)
|
|
]
|
|
BYTE_SHIFTS = [np.uint64(0), np.uint64(8)]
|
|
|
|
# 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):
|
|
super(HGRBitmap, self).__init__(palette, main_memory, None)
|
|
|
|
@staticmethod
|
|
def _make_header(col: IntOrArray) -> IntOrArray:
|
|
"""Extract values to use as header of next column.
|
|
|
|
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) ^ (
|
|
(col & np.uint64(0b11 << 17)) >> np.uint64(17))
|
|
)
|
|
|
|
def _body(self) -> np.ndarray:
|
|
"""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)
|
|
|
|
return (
|
|
(even << 3) + ((odd & 0x7f) << 12) + ((odd & 0x80) << 4)
|
|
)
|
|
|
|
@staticmethod
|
|
def _make_footer(col: IntOrArray) -> IntOrArray:
|
|
"""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)
|
|
|
|
@staticmethod
|
|
@functools.lru_cache(None)
|
|
def byte_offset(page_offset: int, is_aux: bool) -> int:
|
|
"""Returns 0..1 offset in packed representation for page_offset."""
|
|
|
|
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,
|
|
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) + (
|
|
(int7 & 0x40) << 6) +
|
|
# 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)
|
|
)
|
|
|
|
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
|
|
|
|
# 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
|
|
hp = (h & 0x80) >> 7
|
|
res = cls._double_pixels(h & 0x7f) >> (11 - hp)
|
|
|
|
if byte_offset == 0:
|
|
# Offset 0: bbBAaaaaaaaHhh
|
|
b = (masked_val >> 3) & 0xff
|
|
bp = (b & 0x80) >> 7
|
|
else:
|
|
# Offset 1: ffFbbbbbbbBAaa
|
|
bp = (masked_val >> 3) & 0x01
|
|
b = ((masked_val >> 4) & 0x7f) ^ (bp << 7)
|
|
|
|
# Mask out current contents in case we are overwriting the extended
|
|
# high bit from previous screen byte
|
|
res &= ~((2 ** 14 - 1) << (3 + bp))
|
|
res ^= cls._double_pixels(b & 0x7f) << (3 + bp)
|
|
|
|
f = ((masked_val >> 12) & 0b11) ^ (
|
|
(masked_val >> 11) & 0b01) << 7
|
|
fp = (f & 0x80) >> 7
|
|
|
|
# Mask out current contents in case we are overwriting the extended
|
|
# high bit from previous screen byte
|
|
res &= ~((2 ** 4 - 1) << (17 + fp))
|
|
res ^= cls._double_pixels(f & 0x7f) << (17 + fp)
|
|
return res & (2 ** 21 - 1)
|
|
|
|
@staticmethod
|
|
def masked_update(
|
|
byte_offset: int,
|
|
old_value: IntOrArray,
|
|
new_value: np.uint8) -> IntOrArray:
|
|
"""Update int/array to store new value at byte_offset in every entry.
|
|
|
|
Does not patch up headers/footers of neighbouring columns.
|
|
"""
|
|
|
|
if byte_offset == 0:
|
|
# Mask out 8-bit value where update will go
|
|
masked_value = old_value & (~np.uint64(0xff << 3))
|
|
|
|
update = np.uint64(new_value) << np.uint64(3)
|
|
return masked_value ^ update
|
|
else:
|
|
# Mask out 8-bit value where update will go
|
|
masked_value = old_value & (~np.uint64(0xff << 11))
|
|
|
|
# shift palette bit into position 0
|
|
shifted_new_value = (
|
|
(new_value & 0x7f) << 1) ^ (
|
|
(new_value & 0x80) >> 7)
|
|
update = np.uint64(shifted_new_value) << np.uint64(11)
|
|
return masked_value ^ update
|
|
|
|
|
|
class DHGRBitmap(Bitmap):
|
|
"""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'
|
|
|
|
# Packed representation is 3 + 28 + 3 = 34 bits
|
|
HEADER_BITS = np.uint64(3)
|
|
BODY_BITS = np.uint64(28)
|
|
FOOTER_BITS = np.uint64(3)
|
|
|
|
# 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 uint13 possible
|
|
# values and nominal colour pixels, but with different initial
|
|
# phases:
|
|
# AUX 0: 0 (1 at start of 3-bit header)
|
|
# MAIN 0: 3 (0)
|
|
# AUX 1: 2 (3)
|
|
# 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)
|
|
|
|
return (
|
|
(aux[:, 0::2] << 3) +
|
|
(main[:, 0::2] << 10) +
|
|
(aux[:, 1::2] << 17) +
|
|
(main[:, 1::2] << 24)
|
|
)
|
|
|
|
@staticmethod
|
|
def _make_footer(col: IntOrArray) -> IntOrArray:
|
|
"""Extract lower 3 bits of body for footer of previous column."""
|
|
return (col & np.uint64(0b111 << 3)) << np.uint64(28)
|
|
|
|
@staticmethod
|
|
@functools.lru_cache(None)
|
|
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
|
|
return 0
|
|
else: # main memory
|
|
if is_odd:
|
|
return 3
|
|
else:
|
|
return 1
|
|
|
|
@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:
|
|
offsets = (1, 3)
|
|
|
|
return offsets
|
|
|
|
@classmethod
|
|
def to_dots(cls, masked_val: int, byte_offset: int) -> int:
|
|
"""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
|
|
|
|
@staticmethod
|
|
def masked_update(
|
|
byte_offset: int,
|
|
old_value: IntOrArray,
|
|
new_value: np.uint8) -> IntOrArray:
|
|
"""Update int/array to store new value at byte_offset in every entry.
|
|
|
|
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)))
|
|
|
|
update = (new_value & np.uint64(0x7f)) << np.uint64(
|
|
7 * byte_offset + 3)
|
|
return masked_value ^ update
|