Image processor memory for expediting memory operations

A graphics memory system for effecting an algebraic logic operation between an operand of a given memory cell in said graphics memory system and at least one other operand and leaving the results thereof in the given memory cell with no more than one write to the given memory cell and without having to extract the operand therefrom, said graphics memory system comprising:

• a memory cell array for storing binary data, cells of said memory cell array having memory cell modification means for receiving control instructions and performing logic operations according to the control instructions within memory cells of said memory cell array,
• data storage selection means for addressing cells in said memory cell array,
• raster opcode decode means for decoding a given raster opcode and at least said one other operand and generating a control output accordingly, said raster opcode specifying said algebraic logic operation to be effected as required for implementing a predetermined raster operation, and said control output being representative of the control instruction required if any for effecting said algebraic logic operation between the one other operand and the operand of the given memory cell as addressed by said data storage selection means so that the logic operation performed within the given memory cell is operative for modifying the operand therein so as to leave the results of said algebraic logic operation with the given memory cell, and
• means for writing the control output of said raster opcode decode means as the control instruction to the memory cell modification means of the given memory cell when the operational effect of said algebraic logic operation is dependent upon the operand of the given memory cell.