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extra trim applied to 'replace' argument (in case lua_Unsigned is

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larger than 32 bits)
This commit is contained in:
Roberto Ierusalimschy 2013-04-16 15:39:37 -03:00
parent 07f861385e
commit 44358e0206
1 changed files with 8 additions and 6 deletions
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14
lbitlib.c
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@ -1,5 +1,5 @@
/*
** $Id: lbitlib.c,v 1.17 2013/02/21 13:44:53 roberto Exp roberto $
** $Id: lbitlib.c,v 1.18 2013/03/19 13:19:12 roberto Exp roberto $
** Standard library for bitwise operations
** See Copyright Notice in lua.h
*/
@ -19,7 +19,12 @@
#endif
#define ALLONES (~(((~(lua_Unsigned)0) << (LUA_NBITS - 1)) << 1))
/* type with (at least) LUA_NBITS bits */
typedef unsigned long b_uint;
#define ALLONES (~(((~(b_uint)0) << (LUA_NBITS - 1)) << 1))
/* macro to trim extra bits */
#define trim(x) ((x) & ALLONES)
@ -29,9 +34,6 @@
#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);
@ -165,7 +167,7 @@ static int fieldargs (lua_State *L, int farg, int *width) {
static int b_extract (lua_State *L) {
int w;
b_uint r = luaL_checkunsigned(L, 1);
b_uint r = trim(luaL_checkunsigned(L, 1));
int f = fieldargs(L, 2, &w);
r = (r >> f) & mask(w);
lua_pushunsigned(L, r);