Hardware branching employing loop control registers loaded according to status of sections of an arithmetic logic unit divided into a plurality of sections

摘要

Conditional hardware branching employs zero overhead loop logic and writing to a loop count register within a program loop. The zero overhead loop logic includes a program counter (701), loop end registers (711, 712, 713), loop start registers (721, 722, 723), loop counter registers (731, 732, 733), comparators (715, 716, 717) and loop priority logic (725). Normally the program counter (701) is incremented each cycle. The comparators (715, 716, 717) compare the address stored in the program counter (701) with respective loop end registers (711, 712, 713). If the address in the program counter (701) equals a loop end address, loop priority logic (725) decrements the loop count register and loads the program counter with the loop start address in loop start register. Hardware looping involves loading a loop count register during program loop operation. An arithmetic logic unit operation generates a status bit loaded into a status register or is split into sections and generates a status bit for each section stored in a multiple flags register (211) used to load the loop. count register. If this is zero then the loop priority logic reloads the program counter (701) with the loop start address and repeats the loop. If this is nonzero, program counter (701) may increment normally or will be loaded with the loop start address of a higher priority loop.