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Depth-schedule finar adder.

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nella 2026-06-03 15:35:17 +02:00
parent ba7173a469
commit afabf72e23
4 changed files with 45 additions and 30 deletions
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10
kernel/compressor_tree.h
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@ -29,8 +29,9 @@ YOSYS_NAMESPACE_BEGIN
namespace CompressorTree
{
// Width threshold below which a ripple is preferred over parallel-prefix
// Width and depth thresholds below which a ripple is preferred over parallel-prefix
constexpr int RIPPLE_PREFIX_THRESHOLD = 16;
constexpr int PREFIX_DEPTH_THRESHOLD = 5;
enum class Strategy {
FA_ONLY, // 3:2 compressors
@ -80,11 +81,12 @@ std::vector<DepthSig> generate_partial_products(Module *module, SigSpec a, SigSp
* @sigs: Vector of input signals (operands) to be reduced
* @width: Target bit-width to which all operands will be zero-extended
* @strategy: Compression strategy to use
* @compressor_count: Optional pointer to return the number of $fa cells emitted
* @out_compressor_count: Optional pointer to return the number of $fa cells emitted
* @out_final_depth: Optional pointer to return the final depth of the scheduled tree
*
* Return: The final two reduced operands, that are to be fed into an adder
*/
std::pair<SigSpec, SigSpec> reduce_scheduled(Module *module, std::vector<DepthSig> operands, int width, Strategy strategy, int *compressor_count = nullptr);
std::pair<SigSpec, SigSpec> reduce_scheduled(Module *module, std::vector<DepthSig> operands, int width, Strategy strategy, int *out_compressor_count = nullptr, int *out_final_depth = nullptr);
/**
* emit_kogge_stone() - Emit a Kogge-Stone parallel-prefix adder
@ -107,7 +109,7 @@ void emit_kogge_stone(Module *module, SigSpec a, SigSpec b, SigSpec y);
*/
Cell *emit_final_adder(Module *module, SigSpec a, SigSpec b, SigSpec y, FinalAdder choice);
FinalAdder pick_final_adder(int width, FinalMode mode);
FinalAdder pick_final_adder(int width, int final_depth, FinalMode mode);
} // namespace CompressorTree