mirror of https://github.com/bsnes-emu/bsnes.git
68 lines
1.7 KiB
C
68 lines
1.7 KiB
C
/*
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libco.ucontext (2008-01-28)
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author: Nach
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license: public domain
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*/
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/*
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* WARNING: the overhead of POSIX ucontext is very high,
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* assembly versions of libco or libco_sjlj should be much faster
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*
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* This library only exists for two reasons:
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* 1 - as an initial test for the viability of a ucontext implementation
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* 2 - to demonstrate the power and speed of libco over existing implementations,
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* such as pth (which defaults to wrapping ucontext on unix targets)
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*
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* Use this library only as a *last resort*
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*/
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#define LIBCO_C
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#include "libco.h"
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#include <stdlib.h>
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#include <ucontext.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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static thread_local ucontext_t co_primary;
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static thread_local ucontext_t *co_running = 0;
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cothread_t co_active() {
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if(!co_running) co_running = &co_primary;
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return (cothread_t)co_running;
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}
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cothread_t co_create(unsigned int heapsize, void (*coentry)(void)) {
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if(!co_running) co_running = &co_primary;
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ucontext_t *thread = (ucontext_t*)malloc(sizeof(ucontext_t));
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if(thread) {
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if((!getcontext(thread) && !(thread->uc_stack.ss_sp = 0)) && (thread->uc_stack.ss_sp = malloc(heapsize))) {
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thread->uc_link = co_running;
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thread->uc_stack.ss_size = heapsize;
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makecontext(thread, coentry, 0);
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} else {
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co_delete((cothread_t)thread);
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thread = 0;
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}
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}
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return (cothread_t)thread;
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}
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void co_delete(cothread_t cothread) {
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if(cothread) {
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if(((ucontext_t*)cothread)->uc_stack.ss_sp) { free(((ucontext_t*)cothread)->uc_stack.ss_sp); }
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free(cothread);
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}
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}
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void co_switch(cothread_t cothread) {
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ucontext_t *old_thread = co_running;
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co_running = (ucontext_t*)cothread;
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swapcontext(old_thread, co_running);
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}
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#ifdef __cplusplus
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}
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#endif
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