| 摘要 |
A memory store operation comes from one of a pair of registers selected by an arithmetic logic unit condition. An instruction logic circuit (250, 660) controls an addressing circuit (120) to store data in a first register into memory if a selected status bit has a first state and to store data in a second register associated with the first register into memory if the selected status bit has a second state in response to a register pair conditional store instruction. The bits may indicate a negative output of the arithmetic logic unit (230), a carry out signal, an overflow, or a zero output. The register pair conditional store instruction designates a particular one of the status bits to control the conditional store. The instruction logic circuit (250, 660) substitutes the selected status bit for a least significant bit of the register number. Thus memory store is from the first register if the status bit is "1" and is from the second register if the status bit is "0". In a further embodiment the register pair conditional write instruction is conditional. The write operation aborts if the designated condition is true. In the preferred embodiment of this invention, the arithmetic logic unit (230), the status register (210), the data registers (200) and the instruction decode logic (250, 660) are embodied in at least one digital image/graphics processor (71) as a part of a multiprocessor formed in a single integrated circuit (100) used in image processing. |
