/* ** $Id: lbitlib.c,v 1.16 2011/06/20 16:35:23 roberto Exp $ ** Standard library for bitwise operations ** See Copyright Notice in lua.h */ #define lbitlib_c #define LUA_LIB #include "lua.h" #include "lauxlib.h" #include "lualib.h" #include "lj_obj.h" #include "lj_state.h" /* http://lua-users.org/lists/lua-l/2011-01/msg01039.html */ typedef unsigned int lua_Unsigned; #define LUA_UNSIGNED unsigned LUA_INT32 #if !defined(lua_unsigned2number) /* on several machines, coercion from unsigned to double is slow, so it may be worth to avoid */ #define lua_unsigned2number(u) \ (((u) <= (lua_Unsigned)INT_MAX) ? (lua_Number)(int)(u) : (lua_Number)( unsigned int )(u)) #endif #if !defined(lua_lock) #define lua_lock(L) ((void) 0) #define lua_unlock(L) ((void) 0) #endif LUA_API void lua_pushunsigned (lua_State *L, lua_Unsigned u) { lua_Number n=0; lua_lock(L); /* printf("u=%d,%u,%x\n",u,u,u); printf("INT_MAX=%d %u %x, (lua_Unsigned)INT_MAX=%d %u %x (unsigned int)INT_MAX=%d %u %x\n", INT_MAX,INT_MAX,INT_MAX, (lua_Unsigned)INT_MAX,(lua_Unsigned)INT_MAX,(lua_Unsigned)INT_MAX, (unsigned int)INT_MAX,(unsigned int)INT_MAX,(unsigned int)INT_MAX); printf("((u) <= (lua_Unsigned)INT_MAX) :%d\n",(((unsigned int)u) <= (lua_Unsigned)INT_MAX)); printf("(lua_Number)(int)(u) =%d,%u,%x\n",(lua_Number)(int)(u),(lua_Number)(int)(u),(lua_Number)(int)(u)); printf("(lua_Number)(u) =%f,%u,%x\n",(lua_Number)(u),(lua_Number)(u),(lua_Number)(u)); printf("u=%d,%u,%x\n",u,u,u); */ /*printf("n=%d,%u,%x u=%d,%u,%x\n",n,n,n,u,u,u); */ n = lua_unsigned2number(u); /* printf("n=%f \n",n); printf("u=%d %u %x n=%d %u %x\n",u,u,u,n,n,n); printf("n=%d %u %x\n",n,n,n); printf("u=%d,%u,%x\n",u,u,u); */ /* setintptrV(L->top, n); incr_top(L); setnumV(L->top, n); */ setnumV(L->top, n); if (LJ_UNLIKELY(tvisnan(L->top))) setnanV(L->top); /* Canonicalize injected NaNs. */ incr_top(L); /*setnvalue(L->top, n); api_incr_top(L); */ lua_unlock(L); } #define luaL_checkunsigned (lua_Unsigned) luaL_checkinteger /*#define lua_pushunsigned lua_pushinteger*/ /* number of bits to consider in a number */ #if !defined(LUA_NBITS) #define LUA_NBITS 32 #endif #define ALLONES (~(((~(lua_Unsigned)0) << (LUA_NBITS - 1)) << 1)) /* macro to trim extra bits */ #define trim(x) ((x) & ALLONES) /* builds a number with 'n' ones (1 <= n <= LUA_NBITS) */ #define mask(n) (~((ALLONES << 1) << ((n) - 1))) typedef lua_Unsigned b_uint; static b_uint andaux (lua_State *L) { int i, n = lua_gettop(L); b_uint r = ~(b_uint)0; /* printf("1 r=%d,%u,%x\n",r,r,r);*/ for (i = 1; i <= n; i++) r &= luaL_checkunsigned(L, i); /* printf("2 r=%d,%u,%x\n",r,r,r); printf("3 r=%d,%u,%x\n",trim(r),trim(r),trim(r)); */ return trim(r); } static int b_and (lua_State *L) { b_uint r = andaux(L); /* printf("4 r=%d,%u,%x\n",r,r,r);*/ lua_pushunsigned(L, r); return 1; } static int b_test (lua_State *L) { b_uint r = andaux(L); lua_pushboolean(L, r != 0); return 1; } static int b_or (lua_State *L) { int i, n = lua_gettop(L); b_uint r = 0; for (i = 1; i <= n; i++) r |= luaL_checkunsigned(L, i); lua_pushunsigned(L, trim(r)); return 1; } static int b_xor (lua_State *L) { int i, n = lua_gettop(L); b_uint r = 0; for (i = 1; i <= n; i++) r ^= luaL_checkunsigned(L, i); lua_pushunsigned(L, trim(r)); return 1; } static int b_not (lua_State *L) { b_uint r = ~luaL_checkunsigned(L, 1); lua_pushunsigned(L, trim(r)); return 1; } static int b_shift (lua_State *L, b_uint r, int i) { if (i < 0) { /* shift right? */ i = -i; r = trim(r); if (i >= LUA_NBITS) r = 0; else r >>= i; } else { /* shift left */ if (i >= LUA_NBITS) r = 0; else r <<= i; r = trim(r); } lua_pushunsigned(L, r); return 1; } static int b_lshift (lua_State *L) { return b_shift(L, luaL_checkunsigned(L, 1), luaL_checkint(L, 2)); } static int b_rshift (lua_State *L) { return b_shift(L, luaL_checkunsigned(L, 1), -luaL_checkint(L, 2)); } static int b_arshift (lua_State *L) { b_uint r = luaL_checkunsigned(L, 1); int i = luaL_checkint(L, 2); if (i < 0 || !(r & ((b_uint)1 << (LUA_NBITS - 1)))) return b_shift(L, r, -i); else { /* arithmetic shift for 'negative' number */ if (i >= LUA_NBITS) r = ALLONES; else r = trim((r >> i) | ~(~(b_uint)0 >> i)); /* add signal bit */ lua_pushunsigned(L, r); return 1; } } static int b_rot (lua_State *L, int i) { b_uint r = luaL_checkunsigned(L, 1); i &= (LUA_NBITS - 1); /* i = i % NBITS */ r = trim(r); r = (r << i) | (r >> (LUA_NBITS - i)); lua_pushunsigned(L, trim(r)); return 1; } static int b_lrot (lua_State *L) { return b_rot(L, luaL_checkint(L, 2)); } static int b_rrot (lua_State *L) { return b_rot(L, -luaL_checkint(L, 2)); } /* ** get field and width arguments for field-manipulation functions, ** checking whether they are valid */ static int fieldargs (lua_State *L, int farg, int *width) { int f = luaL_checkint(L, farg); int w = luaL_optint(L, farg + 1, 1); luaL_argcheck(L, 0 <= f, farg, "field cannot be negative"); luaL_argcheck(L, 0 < w, farg + 1, "width must be positive"); if (f + w > LUA_NBITS) luaL_error(L, "trying to access non-existent bits"); *width = w; return f; } static int b_extract (lua_State *L) { int w; b_uint r = luaL_checkunsigned(L, 1); int f = fieldargs(L, 2, &w); r = (r >> f) & mask(w); lua_pushunsigned(L, r); return 1; } static int b_replace (lua_State *L) { int w; b_uint r = luaL_checkunsigned(L, 1); b_uint v = luaL_checkunsigned(L, 2); int f = fieldargs(L, 3, &w); int m = mask(w); v &= m; /* erase bits outside given width */ r = (r & ~(m << f)) | (v << f); lua_pushunsigned(L, r); return 1; } static const luaL_Reg bitlib[] = { {"arshift", b_arshift}, {"band", b_and}, {"bnot", b_not}, {"bor", b_or}, {"bxor", b_xor}, {"btest", b_test}, {"extract", b_extract}, {"lrotate", b_lrot}, {"lshift", b_lshift}, {"replace", b_replace}, {"rrotate", b_rrot}, {"rshift", b_rshift}, {NULL, NULL} }; /* http://lua-users.org/lists/lua-l/2011-01/msg01039.html */ /*LUAMOD_API int luaopen_bit32 (lua_State *L) {*/ /* luaL_newlib(L, bitlib);*/ /* return 1;*/ /*} */ int luaopen_bit32 (lua_State *L) { luaL_register(L, "bit32", bitlib); return 1; }