| 1 | /* |
| 2 | libco.x86 (2009-10-12) |
| 3 | author: byuu |
| 4 | license: public domain |
| 5 | */ |
| 6 | |
| 7 | #define LIBCO_C |
| 8 | #include <libco.h> |
| 9 | #include <assert.h> |
| 10 | #include <stdlib.h> |
| 11 | |
| 12 | #ifdef __cplusplus |
| 13 | extern "C" { |
| 14 | #endif |
| 15 | |
| 16 | #if defined(_MSC_VER) |
| 17 | #define fastcall __fastcall |
| 18 | #elif defined(__GNUC__) |
| 19 | #define fastcall __attribute__((fastcall)) |
| 20 | #else |
| 21 | #error "libco: please define fastcall macro" |
| 22 | #endif |
| 23 | |
| 24 | static thread_local long co_active_buffer[64]; |
| 25 | static thread_local cothread_t co_active_handle = 0; |
| 26 | static void (fastcall *co_swap)(cothread_t, cothread_t) = 0; |
| 27 | |
| 28 | //ABI: fastcall |
| 29 | static unsigned char co_swap_function[] = { |
| 30 | 0x89, 0x22, /* mov [edx],esp */ |
| 31 | 0x8b, 0x21, /* mov esp,[ecx] */ |
| 32 | 0x58, /* pop eax */ |
| 33 | 0x89, 0x6a, 0x04, /* mov [edx+0x04],ebp */ |
| 34 | 0x89, 0x72, 0x08, /* mov [edx+0x08],esi */ |
| 35 | 0x89, 0x7a, 0x0c, /* mov [edx+0x0c],edi */ |
| 36 | 0x89, 0x5a, 0x10, /* mov [edx+0x10],ebx */ |
| 37 | 0x8b, 0x69, 0x04, /* mov ebp,[ecx+0x04] */ |
| 38 | 0x8b, 0x71, 0x08, /* mov esi,[ecx+0x08] */ |
| 39 | 0x8b, 0x79, 0x0c, /* mov edi,[ecx+0x0c] */ |
| 40 | 0x8b, 0x59, 0x10, /* mov ebx,[ecx+0x10] */ |
| 41 | 0xff, 0xe0, /* jmp eax */ |
| 42 | }; |
| 43 | |
| 44 | #ifdef _WIN32 |
| 45 | #include <windows.h> |
| 46 | |
| 47 | static void co_init(void) |
| 48 | { |
| 49 | DWORD old_privileges; |
| 50 | VirtualProtect(co_swap_function, |
| 51 | sizeof co_swap_function, PAGE_EXECUTE_READWRITE, &old_privileges); |
| 52 | } |
| 53 | #else |
| 54 | #include <unistd.h> |
| 55 | #include <sys/mman.h> |
| 56 | |
| 57 | static void co_init(void) |
| 58 | { |
| 59 | unsigned long addr = (unsigned long)co_swap_function; |
| 60 | unsigned long base = addr - (addr % sysconf(_SC_PAGESIZE)); |
| 61 | unsigned long size = (addr - base) + sizeof co_swap_function; |
| 62 | mprotect((void*)base, size, PROT_READ | PROT_WRITE | PROT_EXEC); |
| 63 | } |
| 64 | #endif |
| 65 | |
| 66 | static void crash(void) |
| 67 | { |
| 68 | assert(0); /* called only if cothread_t entrypoint returns */ |
| 69 | } |
| 70 | |
| 71 | cothread_t co_active(void) |
| 72 | { |
| 73 | if (!co_active_handle) |
| 74 | co_active_handle = &co_active_buffer; |
| 75 | return co_active_handle; |
| 76 | } |
| 77 | |
| 78 | cothread_t co_create(unsigned int size, void (*entrypoint)(void)) |
| 79 | { |
| 80 | cothread_t handle; |
| 81 | if (!co_swap) |
| 82 | { |
| 83 | co_init(); |
| 84 | co_swap = (void (fastcall*)(cothread_t, cothread_t))co_swap_function; |
| 85 | } |
| 86 | |
| 87 | if (!co_active_handle) |
| 88 | co_active_handle = &co_active_buffer; |
| 89 | |
| 90 | size += 256; /* allocate additional space for storage */ |
| 91 | size &= ~15; /* align stack to 16-byte boundary */ |
| 92 | |
| 93 | if ((handle = (cothread_t)malloc(size))) |
| 94 | { |
| 95 | long *p = (long*)((char*)handle + size); /* seek to top of stack */ |
| 96 | *--p = (long)crash; /* crash if entrypoint returns */ |
| 97 | *--p = (long)entrypoint; /* start of function */ |
| 98 | *(long*)handle = (long)p; /* stack pointer */ |
| 99 | } |
| 100 | |
| 101 | return handle; |
| 102 | } |
| 103 | |
| 104 | void co_delete(cothread_t handle) |
| 105 | { |
| 106 | free(handle); |
| 107 | } |
| 108 | |
| 109 | void co_switch(cothread_t handle) |
| 110 | { |
| 111 | register cothread_t co_previous_handle = co_active_handle; |
| 112 | co_swap(co_active_handle = handle, co_previous_handle); |
| 113 | } |
| 114 | |
| 115 | #ifdef __cplusplus |
| 116 | } |
| 117 | #endif |