Image Number 5 for United States Patent #7788469.
A hardware accelerator is used to execute a floating-point byte-code in an information processing device. For a floating-point byte-code, a byte-code accelerator BCA feeds an instruction stream for using a FPU to a CPU. When the FPU is used, first the data is transferred to the FPU register from a general-purpose register, and then an FPU operation is performed. For data, such as a denormalized number, that cannot be processed by the FPU, in order to call a floating-point math library of software, the processing of the BCA is completed and the processing moves to processing by software. In order to realize this, data on a data transfer bus from the CPU to the FPU is snooped by the hardware accelerator, and a cancel request is signaled to the CPU to inhibit execution of the FPU operation when corresponding data is detected in a data checking part.
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