Dual fixed geometry fast fourier transform (FFT)

An apparatus comprising:

• a memory storing a first instruction and a second instruction;
• and
• a processor coupled to the memory, the processor comprising a common data path, a first input/output network, and a second input/output network and configured to perform operations comprising:
• executing the first instruction to perform a first fast Fourier transform (FFT) operation on a set of inputs in a time domain to produce first data in a frequency domain, wherein the set of inputs is in a first order and wherein the first data in the frequency domain is in a second order, wherein performing the first FFT operation includes use of the common data path in conjunction with the first input/output network, and wherein the first input/output network comprises one of a shuffle input/output network and a deal input/output network;
• performing an operation on the first data in the frequency domain to produce second data in the frequency domain, wherein the second data in the frequency domain is in the second order;
• and
• executing the second instruction to perform a second FFT operation on the second data in the frequency domain to produce third data in the time domain, wherein the third data in the time domain is in the first order, wherein the first order is one of a normal input order and a bit-reversed input order and the second order is the other of the normal input order and the bit-reversed input order, wherein performing the second FFT operation includes use of the common data path in conjunction with the second input/output network, and wherein the second input/output network comprises the other of the shuffle input/output network and the deal input/output network.

An apparatus comprising:

• means for storing a first instruction and a second instruction;
• and
• means for processing the first instruction and the second instruction, wherein the means for processing comprises:
• a common data path;
• a first input/output network;
• a second input/output network;
• means for executing the first instruction to perform a first fast Fourier transform (FFT) operation on a set of inputs in a time domain to produce first data in a frequency domain, wherein the set of inputs is in a first order and wherein the first data in the frequency domain is in a second order, wherein performing the first FFT operation includes use of the common data path in conjunction with the first input/output network, and wherein the first input/output network comprises one of a shuffle input/output network and a deal input/output network;
• means for performing an operation on the first data in the frequency domain to produce second data in the frequency domain, wherein the second data in the frequency domain is in the second order;
• and
• means for executing the second instruction to perform a second FFT operation on the second data in the frequency domain to produce third data in the time domain, wherein the third data in the time domain is in the first order, wherein the first order is one of a normal input order and a bit-reversed input order and the second order is the other of the normal input order and the bit-reversed input order, wherein performing the second FFT operation includes use of the common data path in conjunction with the second input/output network, and wherein the second input/output network comprises the other of the shuffle input/output network and the deal input/output network.

A non-transitory computer-readable medium including program code that, when executed by a processor comprising a common data path, a first input/output network, and a second input/output network, causes the processor to perform operations comprising:

• executing a first instruction at a processor to perform a first fast Fourier transform (FFT) operation on a set of inputs in a time domain to produce first data in a frequency domain, wherein the set of inputs is in a first order, and wherein the first data in the frequency domain is in a second order, wherein performing the first FFT operation includes use of the common data path in conjunction with the first input/output network, and wherein the first input/output network comprises one of a shuffle input/output network and a deal input/output network;
• performing an operation on the first data in the frequency domain to produce second data in the frequency domain, wherein the second data in the frequency domain is in the second order;
• and
• executing a second instruction at the processor to perform a second FFT operation on the second data in the frequency domain to produce third data in the time domain, wherein the third data in the time domain is in the first order, wherein the first order is one of a normal input order and a bit-reversed input order and the second order is the other of the normal input order and the bit-reversed input order, wherein performing the second FFT operation includes use of the common data path in conjunction with the second input/output network, and wherein the second input/output network comprises the other of the shuffle input/output network and the deal input/output network.