56 lines
2.4 KiB
C++
56 lines
2.4 KiB
C++
/***************************************************************************************
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* This file includes most utilized functions for the DecoderLibrary data structure
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***************************************************************************************/
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#include <cmath>
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#include "vtr_assert.h"
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#include "decoder_library_utils.h"
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/***************************************************************************************
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* NOTE: This function is mainly designed for local decoders inside multiplexers
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* Find the size of address lines for a decoder with a given data output size
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* Addr lines
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* | | ... |
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* v v v
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* +-----------+
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* / Local \
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* / Decoder \
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* +-----------------+
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* | | | ... | | |
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* v v v v v v
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* Data outputs
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*
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* The outputs are assumes to be one-hot codes (at most only one '1' exist)
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* Considering this fact, there are only num_of_outputs + 1 conditions to be encoded.
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* Therefore, the number of inputs is ceil(log(num_of_outputs+1)/log(2))
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* We plus 1, which is all-zero condition for outputs
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***************************************************************************************/
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size_t find_mux_local_decoder_addr_size(const size_t& data_size) {
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/* if data size is 1, it is an corner case for the decoder (addr = 1) */
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if (1 == data_size) {
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return 1;
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}
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VTR_ASSERT (2 <= data_size);
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return ceil(log(data_size) / log(2));
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}
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/***************************************************************************************
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* Try to find if the decoder already exists in the library,
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* If there is no such decoder, add it to the library
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***************************************************************************************/
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DecoderId add_mux_local_decoder_to_library(DecoderLibrary& decoder_lib,
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const size_t data_size) {
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size_t addr_size = find_mux_local_decoder_addr_size(data_size);
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DecoderId decoder_id = decoder_lib.find_decoder(addr_size, data_size, false, false, true);
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if (DecoderId::INVALID() == decoder_id) {
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/* Add the decoder */
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return decoder_lib.add_decoder(addr_size, data_size, false, false, true);
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}
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/* There is already a decoder in the library, return the decoder id */
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return decoder_id;
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}
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