EP0197413A2
Expired / Lapsed
EP
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Frame buffer memory
Assignee: Tektronix Inc
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Filing: 1986-03-24
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Granted: —
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Expires: 2006-03-24
Abstract
Abstract 57 A frame buffer memory has a random access memory (RAM) for storing pixel data words, each word containing pixel data corresponding to a separate set of a plurality pixels along a horizontal raster line of a screen display. Each word is separately addressed. The RAM is organized into tiles, with 3 ach tile comprising an array of pixel data word rows and columns corresponding to a separate rectangular subset of horizontally and vertically contiguous display pixels. The RAM is addressed by sequentially applying row and column addresses. A first subset of the column address determines which pixel word row within each tile is addressed, while and a second subset of the column address determines which pixel word column within each tile is addressed. All other bits of the row and column addresses determine which tile is addressed. Means are provided to selectively increment or decrement the first and second subsets of the column address without changing any other address bits, such that words within a selected tile row or column may be successively addressed allowing rapid reading and writing of sequences of pixel data corresponding to contiguous rows or columns of display pixels. A first-in, first-out buffer, provided to store the sequences of data read from the RAM, also includes a barrel shifter to shift bit positions of the data words so stored to facilitate proper pixel alignment during a horizontal scrolling operation. A logic circuit is provided to rapidly modify sequences of data read from the RAM and stored in the buffer prior to rewriting the data to the RAM thereby allowing rapid alteration of pixel attributes.
Inventors
- 👤 David L. Knierim
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 03:19
CPC Classifications
G; G09; G09G; G09G5/00; G09G5/34; G09G5/346; G09G5/36; G09G5/39; G09G5/393
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
178 words
An apparatus for storing and modifying a screen image consisting of rows and columns of pixels, each such pixel having attributes controlled according to stored corresponding pixel data, said apparatus comrising: a random access memory (RAM) for storing the pixel data, said pixel data being stored in said RAM in words, each said word containing pixel data corresponding to a separate set of a plurality of horizontally contiguous pixels, and each word being separately addressed, said words being arranged in tiles, each tile comprising an array of pixel data word rows and columns corresponding to a separate rectangular subset of horizontally and vertically contiguous pixels, and means for addressing said RAM by sequentially applying a first and then a second set of address bits, a first subset of said second address bit set determining which pixel word row within each tile is addressed, and a second subset of said second address bit set determining which pixel word column within each tile is addressed, other bits of said first and second address bits determining which tile is being addressed.
Claim 2
Independent Claim
178 words
An apparatus for storing and modifying a screen image consisting of rows and columns of pixels, each such pixel having attributes controlled according to stored corresponding pixel data, said apparatus comrising: a random access memory (RAM) for storing the pixel data, said pixel data being stored in said RAM in words, each said word containing pixel data corresponding to a separate set of a plurality of horizontally contiguous pixels, and each word being separately addressed, said words being arranged in tiles, each tile comprising an array of pixel data word rows and columns corresponding to a separate rectangular subset of horizontally and vertically contiguous pixels, and means for addressing said RAM by sequentially applying a first and then a second set of address bits, a first subset of said second address bit set determining which pixel word row within each tile is addressed, and a second subset of said second address bit set determining which pixel word column within each tile is addressed, other bits of said first and second address bits determining which tile is being addressed.
Claim 3
Dependent Claim
78 words
An apparatus as in claim 1 further comprising: means to selectively increment or decrement said first subset of said second set of address bits without changing any other address bits, such that pixel words within a selected tile row are successively addressed, and means to selectively increment or decrement said second subset of said second set of address bits without changing any other address bits, such that pixel words within a selected tile column are suces- sively addressed.
Claim 4
Dependent Claim
42 words
An apparatus as in claim 1 further comprising: means to read said pixel data words as they are - addressed; and means to store successively read pixel data words and to output said pixel data words in the same order as read.
Claim 5
Dependent Claim
27 words
An apparatus as in claim 3 wherein said storage and outputting of said pixel data words by said storage means are synchronized to a system clock signal.
Claim 6
Dependent Claim
36 words
An apparatus as in claim 1 further comprising: means to read said pixel data words as they are addressed; and means to store successively read pixel data words and to output bit shifted pixel data words.
Claim 7
Dependent Claim
101 words
An apparatus as in claim 5 wherein said storage means comprises;: first means for receiving and storing a first sequence of data words, and for outputting said first data word sequence in the same order as it is received; means to store a next to last data word outputted by said first means; means to output a second data word sequence, each word thereof comprising a selected number of bits of said last data output word and said next to last data output word; and second means for receiving and storing said second sequence of data words and outputting is received.
Claim 8
Dependent Claim
66 words
An apparatus as in claim 3 further comprising: means to generate a modified data word, the state of each bit thereof being controlled by the collective states of corresponding bits of a plurality of applied input words according to a selected rule data word, a current output word of said means to store being applied as one of said input data words to said generating means.
Claim 9
Dependent Claim
74 words
An apparatus as in claim 7 wherein said generating means comprises: a plurality of multiplexers, each such multiplexer outputting a separate bit of the modified data word, having a separate switching control input for corresponding bits of each applied input data word, and having a rule data word input, the collective state of said corresponding input word bits determining which bit of said rule data word controls the state of the multiplexer output bit.
Claim 10
Independent Claim
266 words
An apparatus for storing and modifying a screen image consisting of rows and columns of pixels, each such pixel having attributes controlled according to stored corresponding pixel data, said apparatus comrising: a random access memory (RAM) for storing the pixel data, said pixel data being stored in said RAM in words, each said word containing pixel data corresponding to a set of a plurality of horizontally contiguous pixels, and each word being separately addressed, said words being arranged in tiles, each tile comprising an array of pixel data word rows and columns corresponding to a separate rectangular subset of horizontally and vertically contiguous pixels, said RAM being addressed by applying a first and a second set of address bits, a first subset of said second address bit set determining which pixel word row within each tile is addressed, and a second subset of said second address bit set determining which pixel word column within each tile is addressed, other bits of said first and second address bits determining which tile is being addressed; means to selectively increment or decrement said first subset of said second set of address bits without changing any other address bits, such that words within a selected tile row are successively addressed; means to selectively increment or decrement said second subset of said second set of address bits without changing any other address bits, such that words with a selected tile column are successively addressed; means to read said pixel data words as they are addressed; and means to store successively read pixel data words and to output said pixel data words.
Claim 11
Independent Claim
266 words
An apparatus for storing and modifying a screen image consisting of rows and columns of pixels, each such pixel having attributes controlled according to stored corresponding pixel data, said apparatus comrising: a random access memory (RAM) for storing the pixel data, said pixel data being stored in said RAM in words, each said word containing pixel data corresponding to a set of a plurality of horizontally contiguous pixels, and each word being separately addressed, said words being arranged in tiles, each tile comprising an array of pixel data word rows and columns corresponding to a separate rectangular subset of horizontally and vertically contiguous pixels, said RAM being addressed by applying a first and a second set of address bits, a first subset of said second address bit set determining which pixel word row within each tile is addressed, and a second subset of said second address bit set determining which pixel word column within each tile is addressed, other bits of said first and second address bits determining which tile is being addressed; means to selectively increment or decrement said first subset of said second set of address bits without changing any other address bits, such that words within a selected tile row are successively addressed; means to selectively increment or decrement said second subset of said second set of address bits without changing any other address bits, such that words with a selected tile column are successively addressed; means to read said pixel data words as they are addressed; and means to store successively read pixel data words and to output said pixel data words.
Claim 12
Dependent Claim
25 words
An apparatus as in claim 9 wherein said outputting of said pixel data words by said storage means is synchronized to a system clock signal.
Claim 13
Dependent Claim
66 words
An apparatus as in claim 9 further comprising: means to generate a modified data word, the state of each bit thereof being controlled by the collective state of corresponding bits of a plurality of applied input words according to a selected rule data word, a current output word of said means to store being applied as one of said input data words to said generating means.
Claim 14
Dependent Claim
74 words
An apparatus as in claim 9 wherein said generating means comprises: a plurality of multiplexers, each such multiplexer outputting a separate bit of the modified data word, having a separate switching control input for corresponding bits of each applied input data word, and having a rule data word input, the collective state of said corresponding input word bits determining which bit of said rule data word controls the state of the multiplexer output bit.
Claim 15
Independent Claim
267 words
An apparatus for controlling an image consisting of rows and columns of pixels, each such pixel having attributes controlled according to corresponding pixel data, said apparatus comrising: a random access memory (RAM) for storing the pixel data, said pixel data being stored in said RAM in words, each said word containing pixel data corresponding to a separate set of a plurality of horizontally contiguous pixels, and each word being separately addressed, said words being arranged in tiles, each tile comprising an array of pixel data word rows and columns corresponding to a separate rectangular subset of horizontally and vertically contiguous pixels, said RAM being addressed by sequentially applying a first and then a second set of address bits, a first subset of said second address bit set determining which pixel word row within each tile is addressed, and a second subset of said second address bit set determining which pixel word column within each tile is addressed, all other bits of said first and second address bits determining which tile is being addressed; means to selectively increment or decrement said first subset of said second set of address bits without changing any other address bits, such that words within a selected tile row are successively addressed; means to selectively increment or decrement said second subset of said second set of address bits without changing any other address bits, such that words with a selected tile column are successively addressed; means to read said pixel data words as they are addressed; and means to store successively read pixel data words and to output bit shifted pixel data words.
Claim 16
Independent Claim
267 words
An apparatus for controlling an image consisting of rows and columns of pixels, each such pixel having attributes controlled according to corresponding pixel data, said apparatus comrising: a random access memory (RAM) for storing the pixel data, said pixel data being stored in said RAM in words, each said word containing pixel data corresponding to a separate set of a plurality of horizontally contiguous pixels, and each word being separately addressed, said words being arranged in tiles, each tile comprising an array of pixel data word rows and columns corresponding to a separate rectangular subset of horizontally and vertically contiguous pixels, said RAM being addressed by sequentially applying a first and then a second set of address bits, a first subset of said second address bit set determining which pixel word row within each tile is addressed, and a second subset of said second address bit set determining which pixel word column within each tile is addressed, all other bits of said first and second address bits determining which tile is being addressed; means to selectively increment or decrement said first subset of said second set of address bits without changing any other address bits, such that words within a selected tile row are successively addressed; means to selectively increment or decrement said second subset of said second set of address bits without changing any other address bits, such that words with a selected tile column are successively addressed; means to read said pixel data words as they are addressed; and means to store successively read pixel data words and to output bit shifted pixel data words.
Claim 17
Dependent Claim
102 words
4. An apparatus as in claim 13 wherein said storage means comprises: first means for receiving and storing a first sequence of data words, and for outputting said first data word sequence in the same order as it is received; means to store a next to last data word outputted by said first means; means to output a second data word sequence, each word thereof comprising a selected number of bits of said last data output word and said next to last data output word; and second means for receiving and storing said second sequence of data words, and outputting is received.
Claim 18
Independent Claim
262 words
An apparatus for storing and modifying a screen image consisting of rows and columns of pixels, each such pixel having attributes controlled according to corresponding pixel data, said apparatus comprising: a random access memory (RAM) for storing the pixel data, said pixel data being stored in said RAM in words, each said word containing pixel data corresponding to a separate set of a plurality of horizontally contiguous pixels, and each word being separately addressed, said words being arranged in tiles, each tile comprising an array of pixel data word rows and columns corresponding to a separate rectangular subset of horizontally and vertically contiguous pixels, said RAM being addressed by sequentially applying a first and then a second set of address bits, a first subset of said second address bit set determining which pixel word row within each tile is addressed, and a second subset of said second address bit set determining which pixel word column within each tile is addressed, all other bits of said first and second address bits determining which tile is being addressed; means to read said pixel data words as they are addressed; means to store successively read pixel data words and to output bit shifted pixel data words; and means to generate a modified data word, the state of each bit thereof being controlled by the collective states of corresponding bits of a plurality of applied input words according to a selected rule data word, a current output word of said means to store being applied as one of said input data words to said generating means.
Claim 19
Independent Claim
262 words
An apparatus for storing and modifying a screen image consisting of rows and columns of pixels, each such pixel having attributes controlled according to corresponding pixel data, said apparatus comprising: a random access memory (RAM) for storing the pixel data, said pixel data being stored in said RAM in words, each said word containing pixel data corresponding to a separate set of a plurality of horizontally contiguous pixels, and each word being separately addressed, said words being arranged in tiles, each tile comprising an array of pixel data word rows and columns corresponding to a separate rectangular subset of horizontally and vertically contiguous pixels, said RAM being addressed by sequentially applying a first and then a second set of address bits, a first subset of said second address bit set determining which pixel word row within each tile is addressed, and a second subset of said second address bit set determining which pixel word column within each tile is addressed, all other bits of said first and second address bits determining which tile is being addressed; means to read said pixel data words as they are addressed; means to store successively read pixel data words and to output bit shifted pixel data words; and means to generate a modified data word, the state of each bit thereof being controlled by the collective states of corresponding bits of a plurality of applied input words according to a selected rule data word, a current output word of said means to store being applied as one of said input data words to said generating means.
Claim 20
Dependent Claim
74 words
An apparatus as in claim 15 wherein said generating means comprises: a plurality of multiplexers, each such multiplexer outputting a separate bit of the modified data word, having a separate switching control input for corresponding bits of each applied input data word, and having a rule data word input, the collective state of said corresponding input word bits determining which bit of said rule data word controls the state of the multiplexer output bit.
Claim 21
Independent Claim
114 words
An apparatus for storing and bit shifting a sequence of data words comprising: first means for receiving and storing first sequence of data words, and for outputting said first data word sequence in the same order as it is received; means to store a next to last data word outputted by said first means; means to output a second data word sequence, each word thereof comprising a selected number of bits of said last data output word and said next to last data output word; and second means for receiving and storing said second sequence of data words, and for outputting said second data word sequence in the same order as it is received.
Claim 22
Independent Claim
114 words
An apparatus for storing and bit shifting a sequence of data words comprising: first means for receiving and storing first sequence of data words, and for outputting said first data word sequence in the same order as it is received; means to store a next to last data word outputted by said first means; means to output a second data word sequence, each word thereof comprising a selected number of bits of said last data output word and said next to last data output word; and second means for receiving and storing said second sequence of data words, and for outputting said second data word sequence in the same order as it is received.
Claim 23
Dependent Claim
51 words
An apparatus as in claim 17 where said storage and said outputting of said first sequence of data words by said first means, said storage of said last data word and said outputting of said storage and said second data sequence by said second means are synchronized to a system clock.
Claim 24
Independent Claim
369 words
An apparatus for storing and modifying a screen image consisting of rows and columns of pixels, each such pixel having attributes controlled according to corresponding pixel data, said apparatus comprising: a random access memory (RAM) for storing the pixel data, said pixel data being stored in said RAM in words; each said word containing pixel data corresponding to a separate set of a plurality of horizontally contiguous pixels, and each word being separately addressed, said words being arranged in tiles, each tile comprising an array of pixel data word rows and columns corresponding to a separate rectangular subset of horizontaily and vertically contiguous pixels, said RAM being addressed by sequentially applying a first and then a second set of address bits, a first subset of said second address bit set determining which pixel word row within each tile is addressed, and a second subset of said second address bit set determining which pixel word column within each tile is addressed, all other bits of said first and second address bits determining which tile is being addressed; means to selectively increment or decrement said second subset of said second set of address bits without changing any other address bits, such that words within a selected tile column are successively addressed; first means for receiving and storing a first sequence of data words, and for outputting said first data word sequence in the same order as it is received; means to store a next to last data word outputted by said first means; means to output a second data word sequence, each word thereof comprising a selected number of bits of said last data output word and said next to last data output word; second means for receiving and storing said second sequence of data words, and for outputting said second data word sequence in the same order as it is received; and means to generate a modified data word, the state of each bit thereof being controlled by the collective states of corresponding bits of a plurality of applied input words according to a selected rule data word, a current output word of said means to store being applied as one of said input data words to said generating means.
Claim 25
Independent Claim
369 words
An apparatus for storing and modifying a screen image consisting of rows and columns of pixels, each such pixel having attributes controlled according to corresponding pixel data, said apparatus comprising: a random access memory (RAM) for storing the pixel data, said pixel data being stored in said RAM in words; each said word containing pixel data corresponding to a separate set of a plurality of horizontally contiguous pixels, and each word being separately addressed, said words being arranged in tiles, each tile comprising an array of pixel data word rows and columns corresponding to a separate rectangular subset of horizontaily and vertically contiguous pixels, said RAM being addressed by sequentially applying a first and then a second set of address bits, a first subset of said second address bit set determining which pixel word row within each tile is addressed, and a second subset of said second address bit set determining which pixel word column within each tile is addressed, all other bits of said first and second address bits determining which tile is being addressed; means to selectively increment or decrement said second subset of said second set of address bits without changing any other address bits, such that words within a selected tile column are successively addressed; first means for receiving and storing a first sequence of data words, and for outputting said first data word sequence in the same order as it is received; means to store a next to last data word outputted by said first means; means to output a second data word sequence, each word thereof comprising a selected number of bits of said last data output word and said next to last data output word; second means for receiving and storing said second sequence of data words, and for outputting said second data word sequence in the same order as it is received; and means to generate a modified data word, the state of each bit thereof being controlled by the collective states of corresponding bits of a plurality of applied input words according to a selected rule data word, a current output word of said means to store being applied as one of said input data words to said generating means.
Claim 26
Dependent Claim
74 words
An apparatus as in claim 19 wherein said generating means comprises: a plurality of multiplexers, each such multiplexer outputting a separate bit of the modified data word, having a separate switching control input for corresponding bits of each applied input data word, and having a rule data word input, the collective state of said corresponding input word bits determining which bit of said rule data word controls the state of the multiplexer output bit.
Claim 27
Dependent Claim
51 words
An apparatus as in claim 19 where said storage and said outputting of said first sequence of data words by said first means, said storage of said last data word and said outputting of said storage and said second data sequence by said second means are synchronized to a system clock.
Claim 28
Independent Claim
181 words
A method for storing and modifying a screen image consisting of rows and columns of pixels, each such pixel having an attribute controlled according to corresponding pixel data stored in a random access memory (RAM), said RAM being addressed by applying a first and a second set of address bits, said method comprising the steps of: a. arranging said pixel data into words each said word containing pixel data corresponding to a separate set of a plurality of horizontally contiguous. pixels; b. arranging said words into tiles, each said tile comprising an array of word rows and columns corresponding to a separate rectangular subset of horizontally and vertically contiguous pixels; and c. storing said pixel data tiles in said RAM such that a first subset of said second address bit set determines which pixel word row within each tile is addressed, such that a second subset of said second address bit set determines which pixel word column within each tile is addressed, and such that other bits of said first and second address bit sets determine which tile is being addressed.
Claim 29
Independent Claim
181 words
A method for storing and modifying a screen image consisting of rows and columns of pixels, each such pixel having an attribute controlled according to corresponding pixel data stored in a random access memory (RAM), said RAM being addressed by applying a first and a second set of address bits, said method comprising the steps of: a. arranging said pixel data into words each said word containing pixel data corresponding to a separate set of a plurality of horizontally contiguous. pixels; b. arranging said words into tiles, each said tile comprising an array of word rows and columns corresponding to a separate rectangular subset of horizontally and vertically contiguous pixels; and c. storing said pixel data tiles in said RAM such that a first subset of said second address bit set determines which pixel word row within each tile is addressed, such that a second subset of said second address bit set determines which pixel word column within each tile is addressed, and such that other bits of said first and second address bit sets determine which tile is being addressed.
Claim 30
Dependent Claim
89 words
A method as in claim 22 further comprising the steps of: d. applying said first set of address bits to said RAM; e. applying said second set of address bits to said RAM to access a selected word; f. modifying said first or said second subset of said second set of address bits; and g. reapplying said modified second set of address bits to said RAM without changing said first set of address bits to access a next word in the same row or column as said selected word.
Claim 31
Dependent Claim
20 words
A method as in claim 23 wherein said first or said second subset is modified either by incrementing or decrementing.
Claim 32
Dependent Claim
38 words
A method as in claim 23 further comprising the steps of: h. reading said selected and said next words as they are accessed; and i. storing said selected and said next words in the order they are read.
Claim 33
Dependent Claim
130 words
A method as in claim 25 further comprising the steps of: j. reapplying another first set of address bits to said RAM and another second set of address bits to said RAM such that said RAM is accessed at an address other than that from which said selected word was read; k. writing said stored selected word to said other address; I. modifying said first or said second subset of said second set of address bits; m. reapplying said modified second set of address bits to said RAM without changing said first set of address bits to access a new next word address in the same row or column as said other address of said selected word; and n. writing said stored next word to said new next word address.
Claim 34
Dependent Claim
142 words
A method as in claim 25 further comprising the step of: j. modifying said stored selected word; k. reapplying another first set of address bits to said RAM and another second set of address bits to said RAM such that said RAM is accessed at an address other than that from which said selected word was read; 1. writing said modified selected word to said other address; m. modifying said stored next word; n. modifying said first or said second subset of said second set. of address bits; o. reapplying said modified second set of address bits to said RAM without changing said first set of address bits to access a new next word address in the same row or column as said other address of said selected word; and p. writing said stored next word to said new next word address.
Claim 35
Dependent Claim
21 words
A method as in claim 27 wherein said modified selected word comprises bits from said selected word and said next word.
References Cited (Backward Citations)
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