1 /* fibers.h -- an extremely simple lightweight thread (fiber) implementation 2 Copyright (C) 2015-2019 Free Software Foundation, Inc. 3 Contributed by Pekka Jaaskelainen <pekka.jaaskelainen@parmance.com> 4 for General Processor Tech. 5 6 Permission is hereby granted, free of charge, to any person obtaining a 7 copy of this software and associated documentation files 8 (the "Software"), to deal in the Software without restriction, including 9 without limitation the rights to use, copy, modify, merge, publish, 10 distribute, sublicense, and/or sell copies of the Software, and to 11 permit persons to whom the Software is furnished to do so, subject to 12 the following conditions: 13 14 The above copyright notice and this permission notice shall be included 15 in all copies or substantial portions of the Software. 16 17 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 18 OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 19 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 20 IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, 21 DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR 22 OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE 23 USE OR OTHER DEALINGS IN THE SOFTWARE. 24 */ 25 26 #ifndef PHSA_RT_FIBERS_H 27 #define PHSA_RT_FIBERS_H 28 29 #include <ucontext.h> 30 31 typedef enum 32 { 33 /* Ready to run. */ 34 FIBER_STATUS_READY, 35 /* Exited by calling fiber_thread_exit. */ 36 FIBER_STATUS_EXITED, 37 /* Joined by the main thread. */ 38 FIBER_STATUS_JOINED 39 } fiber_status_t; 40 41 /* A light weight thread (fiber). */ 42 struct fiber_s 43 { 44 ucontext_t context; 45 volatile fiber_status_t status; 46 struct fiber_s *next; 47 struct fiber_s *prev; 48 }; 49 50 typedef struct fiber_s fiber_t; 51 52 typedef void (*fiber_function_t)(int, int); 53 54 /* Initializes the fiber with the start function given as the first 55 argument, and the argument to pass to the start function, 56 as the second. The allocated stack size is given as the last argument. */ 57 void 58 fiber_init (fiber_t *fiber, fiber_function_t start_function, void *arg, 59 size_t stack_size, size_t stack_align); 60 61 /* Terminates the fiber execution from within the fiber itself. */ 62 void 63 fiber_exit (); 64 65 /* Blocks until the given fiber returns. Frees the resources allocated 66 for the fiber. After join returns, the fiber itself can be deleted. */ 67 void 68 fiber_join (fiber_t *fiber); 69 70 /* Co-operatively transfer execution turn to other fibers. */ 71 void 72 fiber_yield (); 73 74 /* A multi-entry barrier. After the last fiber has reached the 75 barrier, it is automatically re-initialized to the threshold. */ 76 typedef struct 77 { 78 /* The barrier participant count. */ 79 volatile size_t threshold; 80 /* Number of fibers that have reached the barrier. */ 81 volatile size_t reached; 82 /* Number of fibers that are waiting at the barrier. */ 83 volatile size_t waiting_count; 84 } fiber_barrier_t; 85 86 /* Reach the given barrier. Blocks (co-operatively switches the execution 87 fibers) until all other parties have reached it. Returns 0 only in case 88 the calling fiber was the first one to return from the barrier. */ 89 size_t 90 fiber_barrier_reach (fiber_barrier_t *barrier); 91 92 /* Initializes the given barrier. */ 93 void 94 fiber_barrier_init (fiber_barrier_t *barrier, size_t threshold); 95 96 void * 97 fiber_int_args_to_ptr (int arg0, int arg1); 98 99 #endif 100