Adjusting subline address for burst transfer to/from computer memory
View Patent ↗A burst-mode data transfer arrangement for transferring a “LINE” of data, arranged in a four-subline array, between a 32-bit-subline memory and a cache memory having 64 bits per sub-line, where, in every such transfer, four sublines must be transferred successively in one of four different sequences, depending on whether the initial access-subline is subline-#1, -#2, -#3 or -#4; this arrangement being adapted to derive the address of the third subline by: deriving an “access address” for the initial subline of the “LINE” to be transferred; converting the result to binary code form; inverting the fourth bit of this binary code form, and then converting this result to the desired code form, to constitute the address of the third subline (of the four to be transferred).
1. In the burst-mode transfer of one “LINE” of data arranged in a four-subline array, between a first '486-type, 32-bit-subline memory and a second memory having 64 bits per sub-line, where, in every such transfer, four sublines must be transferred successively in one of four different sequences, depending on whether the initial subline is subline-#1, -#2, -#3 or -#4, the steps for deriving the address of the third subline comprising:
placing the “access address” in binary form; and
inverting the fourth bit thereof to thus constitute the address of the third subline in order, of the four sublines to be transferred.
2. A method for the transfer of one “LINE” of data between a first memory and a cache memory, each said LINE having N sublines, these to be transferred in order, this method comprising:
deriving an “access address” for the initial subline of the “LINE” to be transferred;
converting this access address from the original base to binary code form;
inverting the bit of fourth highest significance of this binary code form, and converting the result to the desired base form, to constitute the address of the subline which is third in order of transfer.
3. In a method for the transfer of one “LINE” of data, arranged in “four-sublines”, between a first 32-bit-subline memory and a second cache memory having 64 bits per subline, where, in every such transfer, four sublines must be transferred successively in one of four different sequences, depending on whether the initial subline is subline-#1, -#2, -#3 or -#4, the steps for deriving the address of the third subline to be transferred, comprising:
deriving an “access address” for the initial subline of the “LINE” to be transferred;
converting the result from the original base to binary code form;
inverting the fourth bit of this binary code form, and converting the result to the desired base form, to constitute the address of the third subline of the four successive sublines to be transferred.
4. In the transfer of one “LINE” of data arranged in a four-subline array, between a first 32-bit-subline memory and a second cache memory having 64 bits per subline, where, in every such transfer, four sublines must be transferred successively in one of four different sequences, depending on whether the initial subline is subline-#1, -#2, -#3 or -#4, the steps for deriving the address of the third subline comprising:
placing the “access address” for the first subline to be transferred in binary form; and inverting the fourth most significant bit thereof to thus constitute the “access address” of the third subline to be transferred.
5. A burst-mode data transfer method for transferring a “LINE” of data, arranged in a four-subline array, between a 32-bit-subline memory and a cache memory having 64 bits per sub-line, where, in every such transfer, four sublines must be transferred successively in one of four different sequences, depending on whether the initial access-subline is subline-#1, -#2, #3 or -#4; this method being arranged to derive the address of the third subline of the four to be transferred, and comprising:
deriving an “access address” for the initial subline of the “LINE” to be transferred;
converting the result to binary code form;
inverting the fourth bit of this binary code form, and then
converting this result to the desired code form, to constitute the address of the said third subline.
6. In a burst-mode data transfer arrangement for the burst-mode transfer of one “LINE” of data, arranged in a four-subline array, between a first type, 32-bit-subline memory and a second cache memory having 64 bits per subline, where, in every such transfer, four sublines must be transferred successively in one of four different sequences, depending on whether the initial access-subline is subline #1, #2, #3 or #4, this transfer arrangement being adapted to derive the address of the third subline, the method comprising:
deriving the “access address” of the first subline to be transferred; placing this in binary form; and
inverting the fourth-bit thereof to thus yield the address of the third subline.
7. In a data transfer arrangement for the burst-mode transfer of one “LINE” of data, arranged in a four-subline array, between a first 32-bit-subline memory and a second cache memory having 64 bits per subline, where, in every such transfer, four sublines must be transferred successively in one of four different sequences, depending on whether the first access-subline is subline #1, #2, #3, #4, this transfer arrangement being apt for deriving the address of the third subline, the method comprising:
deriving the “access address” of the first subline to be transferred; placing “access address” in binary form; and inverting the fourth most significant bit thereof to thereby yield the access address of the third subline to be transferred.
8. The method claim 7 , including providing means for said deriving and said inverting in interface means coupled between said first and second memories.