| // |
| // This confidential and proprietary software may be used only as |
| // authorised by a licensing agreement from ARM Limited |
| // (C) COPYRIGHT 2020-2021 ARM Limited |
| // ALL RIGHTS RESERVED |
| // The entire notice above must be reproduced on all authorised |
| // copies and copies may only be made to the extent permitted |
| // by a licensing agreement from ARM Limited. |
| |
| === Control Flow Operators |
| |
| TOSA implements two control flow operators, for conditional branching and loop based control. Both have attributes that are TOSA sub-graphs. |
| |
| ==== COND_IF |
| |
| Evaluates a Boolean condition and then takes one of two distinct execution paths. This implements the semantic if-then-else structure. |
| |
| include::{generated}/operators/COND_IF.adoc[] |
| |
| [source,c++] |
| ---- |
| ERROR_IF(tosa_nesting_depth >= MAX_NESTING); |
| ERROR_IF(tensor_list_shape(input_list) != tosa_input_shape(then_graph)); |
| ERROR_IF(tensor_list_shape(input_list) != tosa_input_shape(else_graph)); |
| ERROR_IF(tensor_list_shape(output_list) != tosa_output_shape(then_graph)); |
| ERROR_IF(tensor_list_shape(output_list) != tosa_output_shape(else_graph)); |
| ERROR_IF(tensor_size(shape) != 1); |
| |
| tosa_nesting_depth++; |
| if (condition[0]) { |
| tosa_execute_graph(then_graph, input_list, output_list); |
| } else { |
| tosa_execute_graph(else_graph, input_list, output_list); |
| } |
| tosa_nesting_depth--; |
| ---- |
| |
| ==== WHILE_LOOP |
| |
| Generates and evaluates a Bool condition and either executes a loop body or exits the loop. This action is performed repeatedly after updating and re-evaluating the Boolean condition every iteration. This implements the semantic foreach or while iterative loop structure. |
| |
| include::{generated}/operators/WHILE_LOOP.adoc[] |
| |
| [source,c++] |
| ---- |
| ERROR_IF(tosa_nesting_depth >= MAX_NESTING); |
| ERROR_IF(tensor_list_shape(input_list) != tosa_list_shape(output_list)); |
| ERROR_IF(tensor_list_shape(input_list) != tosa_input_shape(cond_graph)); |
| ERROR_IF(tensor_list_shape(input_list) != tosa_input_shape(body_graph)); |
| ERROR_IF(tensor_list_shape(input_list) != tosa_output_shape(body_graph)); |
| // Condition graph output must be a single element tensor with a single bool value |
| ERROR_IF(tensor_size(tosa_output_shape(cond_graph)) != 1); |
| ERROR_IF(tosa_output_type(cond_graph) != bool_t); |
| |
| // The iteration number 'i' is included to give unique names to variables |
| // in each iteration of the loop and is not required by implementations |
| int32_t i=0; // iteration number |
| tensor_list_t list[]; // array of tensor lists indexed by iteration |
| bool_t *condition[]; // array of condition tensors indexed by iteration |
| list[i] = input_list; // copy input data as list[0] |
| tosa_nesting_depth++; |
| tosa_execute_graph(cond_graph, list[i], [ condition[i] ]); // initial condition |
| while (condition[i][0]) { |
| tosa_execute_graph(body_graph, list[i], list[i+1]); |
| i = i+1; |
| tosa_execute_graph(cond_graph, list[i], [ condition[i] ]); |
| } |
| tosa_nesting_depth--; |
| output_list = list[i]; |
| ---- |