Patent Number: 6,170,001

Title: System for transfering format data from format register to memory wherein format data indicating the distribution of single or double precision data type in the register bank

Abstract: A data processing apparatus and method is provided, wherein in a first mode of operation, data of a first data type is processed, and in a second mode of operation, data of a second data type consisting of an even multiple of data words is processed. The data processing apparatus comprises a register bank having a plurality of data slots for storing data words of data of said first type data and data words of data of said second type data, and transfer logic, responsive to a store instruction, to control the storing of the data words in the register bank to a memory. Further, a format register is provided for storing format data indicating the distribution in the register bank of data words of data of said first data type and data words of data of said second data type. In said second mode, the transfer logic is responsive to said store instruction specifying an even number of data words to cause those data words to be stored from said register bank to said memory, and is responsive to said store instruction specifying an odd number of data words, to cause the format data from the format register to be stored to said memory along with an even number of data words from the register bank. Hence, in situations where the data in the register bank needs to be temporarily stored to memory for subsequent retrieval into the register bank, all that is required is for the store instruction to be issued in said second mode specifying an odd number of data words, and this will automatically cause the contents of the format register to be stored to memory in addition to the required even number of data words from the register bank.

Inventors: Hinds; Christopher N. (Austin, TX), Seal; David J. (Cambridge, GB)

Assignee: Arm Limited

International Classification: G06F 9/30 (20060101); G06F 9/318 (20060101); G06F 9/312 (20060101); G06F 007/38 ()

Expiration Date: 01/02/2018