77 lines
2.1 KiB
C
77 lines
2.1 KiB
C
#ifndef COROUTINE_EMSCRIPTEN_CONTEXT_H
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#define COROUTINE_EMSCRIPTEN_CONTEXT_H 1
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/* An experimental coroutine wrapper for emscripten
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* Contact on Yusuke Endoh if you encounter any problem about this
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*/
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#pragma once
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#include <assert.h>
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#include <stddef.h>
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#include <emscripten/fiber.h>
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#define COROUTINE __attribute__((noreturn)) void
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#if INTPTR_MAX <= INT32_MAX
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#define COROUTINE_LIMITED_ADDRESS_SPACE
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#endif
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struct coroutine_context;
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typedef COROUTINE(* coroutine_start)(struct coroutine_context *from, struct coroutine_context *self);
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struct coroutine_context
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{
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emscripten_fiber_t state;
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coroutine_start entry_func;
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struct coroutine_context * from;
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};
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COROUTINE coroutine_trampoline(void * _context);
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#define MAIN_ASYNCIFY_STACK_SIZE 65536
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static inline void coroutine_initialize_main(struct coroutine_context * context) {
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static char asyncify_stack[MAIN_ASYNCIFY_STACK_SIZE];
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emscripten_fiber_init_from_current_context(&context->state, asyncify_stack, MAIN_ASYNCIFY_STACK_SIZE);
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}
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#undef MAIN_ASYNCIFY_STACK_SIZE
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static inline void coroutine_initialize(
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struct coroutine_context *context,
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coroutine_start start,
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void *stack,
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size_t size
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) {
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assert(start && stack && size >= 1024);
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uintptr_t addr = (uintptr_t)stack;
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size_t offset = addr & 0xF;
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void *c_stack = (void*)((addr + 0xF) & ~0xF);
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size -= offset;
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size_t c_stack_size = (size / 2) & ~0xF;
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void *asyncify_stack = (void*)((uintptr_t)c_stack + c_stack_size);
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size_t asyncify_stack_size = size - c_stack_size;
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context->entry_func = start;
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emscripten_fiber_init(&context->state, coroutine_trampoline, context, c_stack, c_stack_size, asyncify_stack, asyncify_stack_size);
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}
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static inline struct coroutine_context * coroutine_transfer(struct coroutine_context * current, struct coroutine_context * target)
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{
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struct coroutine_context * previous = target->from;
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target->from = current;
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emscripten_fiber_swap(¤t->state, &target->state);
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target->from = previous;
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return target;
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}
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static inline void coroutine_destroy(struct coroutine_context * context)
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{
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context->from = NULL;
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}
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#endif /* COROUTINE_EMSCRIPTEN_CONTEXT_H */
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