bsnes-libretro/libco/arm.c

83 lines
2.0 KiB
C

#define LIBCO_C
#include "libco.h"
#include "settings.h"
#ifdef LIBCO_MPROTECT
#include <unistd.h>
#include <sys/mman.h>
#endif
#ifdef __cplusplus
extern "C" {
#endif
static thread_local unsigned long co_active_buffer[64];
static thread_local cothread_t co_active_handle = 0;
static void (*co_swap)(cothread_t, cothread_t) = 0;
#ifdef LIBCO_MPROTECT
alignas(4096)
#else
section(text)
#endif
static const unsigned long co_swap_function[1024] = {
0xe8a16ff0, /* stmia r1!, {r4-r11,sp,lr} */
0xe8b0aff0, /* ldmia r0!, {r4-r11,sp,pc} */
0xe12fff1e, /* bx lr */
};
static void co_init() {
#ifdef LIBCO_MPROTECT
unsigned long addr = (unsigned long)co_swap_function;
unsigned long base = addr - (addr % sysconf(_SC_PAGESIZE));
unsigned long size = (addr - base) + sizeof co_swap_function;
mprotect((void*)base, size, PROT_READ | PROT_EXEC);
#endif
}
cothread_t co_active() {
if(!co_active_handle) co_active_handle = &co_active_buffer;
return co_active_handle;
}
cothread_t co_derive(void* memory, unsigned int size, void (*entrypoint)(void)) {
unsigned long* handle;
if(!co_swap) {
co_init();
co_swap = (void (*)(cothread_t, cothread_t))co_swap_function;
}
if(!co_active_handle) co_active_handle = &co_active_buffer;
if(handle = (unsigned long*)memory) {
unsigned int offset = (size & ~15);
unsigned long* p = (unsigned long*)((unsigned char*)handle + offset);
handle[8] = (unsigned long)p;
handle[9] = (unsigned long)entrypoint;
}
return handle;
}
cothread_t co_create(unsigned int size, void (*entrypoint)(void)) {
void* memory = LIBCO_MALLOC(size);
if(!memory) return (cothread_t)0;
return co_derive(memory, size, entrypoint);
}
void co_delete(cothread_t handle) {
LIBCO_FREE(handle);
}
void co_switch(cothread_t handle) {
cothread_t co_previous_handle = co_active_handle;
co_swap(co_active_handle = handle, co_previous_handle);
}
int co_serializable() {
return 1;
}
#ifdef __cplusplus
}
#endif