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Compatible Bit BLT Apparatus

IP.com Disclosure Number: IPCOM000040093D
Original Publication Date: 1987-Sep-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

Aoki, Y: AUTHOR [+2]

Abstract

This Compatible Bit BLT (Bit Block Transfer) apparatus can perform Bit BLT operation in any bus size mode of color display, where the bus means the bus between memory map and color read-write apparatus. However, this concept is also available to the bus between CPU bus and a color read-write apparatus. Before established this apparatus, it was impossible to perform Bit BLT operation in different bus size mode in color display by the same Bit BLT operation unit. Generally Bit BLT has two functions: one is dragging move operation, and the other is raster operation. In this apparatus, the dragging move operation is supported by complement registers 1 and data rotators 2 and rotated latches 3 and dragging move multiplexer 4. The raster operation is performed by logical operation unit 5.

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Compatible Bit BLT Apparatus

This Compatible Bit BLT (Bit Block Transfer) apparatus can perform Bit BLT operation in any bus size mode of color display, where the bus means the bus between memory map and color read-write apparatus. However, this concept is also available to the bus between CPU bus and a color read-write apparatus. Before established this apparatus, it was impossible to perform Bit BLT operation in different bus size mode in color display by the same Bit BLT operation unit. Generally Bit BLT has two functions: one is dragging move operation, and the other is raster operation. In this apparatus, the dragging move operation is supported by complement registers 1 and data rotators 2 and rotated latches 3 and dragging move multiplexer 4. The raster operation is performed by logical operation unit 5. The key feature of this apparatus is the design of the data rotators 2 and the control of the dragging move multiplexer 4. In this explanation, the bus length between the memory plane and the hardware circuit is 8 or 16. According to the bus size, the data rotator 2 should work as two 8-bit rotators or a 16-bit rotator by a control signal. In 16-bit mode, the contents of complement registers (0) and (1) are word data of one color plane and the contents of complement registers (2) and (3) are a word data of the other color plane. Therefore, the output of the rotator is rotated word data of a color plane. In 8-bit mode, the contents of each of the four compl...