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https://github.com/libretro/libretro-common.git
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114 lines
2.4 KiB
C
114 lines
2.4 KiB
C
/*
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libco.sjlj (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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* Note this was designed for UNIX systems. Based on ideas expressed in a paper
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* by Ralf Engelschall.
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* For SJLJ on other systems, one would want to rewrite springboard() and
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* co_create() and hack the jmb_buf stack pointer.
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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 <signal.h>
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#include <setjmp.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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typedef struct
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{
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sigjmp_buf context;
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void (*coentry)(void);
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void *stack;
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} cothread_struct;
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static thread_local cothread_struct co_primary;
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static thread_local cothread_struct *creating, *co_running = 0;
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static void springboard(int ignored)
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{
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if (sigsetjmp(creating->context, 0))
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co_running->coentry();
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}
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cothread_t co_active(void)
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{
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if (!co_running)
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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 size, void (*coentry)(void))
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{
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cothread_struct *thread;
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if (!co_running)
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co_running = &co_primary;
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if ((thread = (cothread_struct*)malloc(sizeof(cothread_struct))))
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{
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stack_t stack;
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stack_t old_stack;
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thread->coentry = thread->stack = 0;
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stack.ss_flags = 0;
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stack.ss_size = size;
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thread->stack = stack.ss_sp = malloc(size);
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if (stack.ss_sp && !sigaltstack(&stack, &old_stack))
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{
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struct sigaction old_handler = {{0}};
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struct sigaction handler = {{0}};
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handler.sa_handler = springboard;
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handler.sa_flags = SA_ONSTACK;
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sigemptyset(&handler.sa_mask);
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creating = thread;
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if (!sigaction(SIGUSR1, &handler, &old_handler))
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{
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if (!raise(SIGUSR1))
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thread->coentry = coentry;
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sigaltstack(&old_stack, 0);
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sigaction(SIGUSR1, &old_handler, 0);
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}
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}
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if (thread->coentry != coentry)
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{
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co_delete(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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{
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if (cothread)
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{
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if (((cothread_struct*)cothread)->stack)
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free(((cothread_struct*)cothread)->stack);
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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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{
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if (!sigsetjmp(co_running->context, 0))
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{
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co_running = (cothread_struct*)cothread;
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siglongjmp(co_running->context, 1);
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}
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}
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#ifdef __cplusplus
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}
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#endif
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