Merge pull request #1916 from bettio/utils-cleanup-and-doc

- Add doxygen documentation to `utils.h` functions that have been introduced
with feature/bigint branch.
- Move bitshift utilities to `utils.h`.
- Fix issue with 60-bits `b` operand in `a bsr b` and `a bsl b`

These changes are made under both the "Apache 2.0" and the "GNU Lesser General
Public License 2.1 or later" license terms (dual license).

SPDX-License-Identifier: Apache-2.0 OR LGPL-2.1-or-later

Author: bettio

src/libAtomVM/bif.c

@@ -1691,32 +1691,6 @@ term bif_erlang_bxor_2(Context *ctx, uint32_t fail_label, int live, term arg1, t
     }
 }
 
-static inline int64_t int64_bsr(int64_t n, unsigned int rshift)
-{
-    return (int64_t) ((n < 0) ? ~(~((uint64_t) n) >> rshift) : (((uint64_t) n) >> rshift));
-}
-
-static inline bool int64_bsl_overflow(int64_t n, unsigned int lshift, int64_t *out)
-{
-    if (lshift >= 64) {
-        *out = 0;
-        return (n != 0);
-    }
-
-    int64_t res = (int64_t) (((uint64_t) n) << lshift);
-    *out = res;
-    int64_t check = int64_bsr(res, lshift);
-    return check != n;
-}
-
-static inline int64_t int64_bsr_safe(int64_t n, unsigned int rshift)
-{
-    if (rshift >= 64) {
-        return n < 0 ? -1 : 0;
-    }
-    return int64_bsr(n, rshift);
-}
-
 term bif_erlang_bsl_2(Context *ctx, uint32_t fail_label, int live, term arg1, term arg2)
 {
     if (LIKELY(term_is_any_integer(arg1) && term_is_non_neg_int(arg2))) {

src/libAtomVM/term_typedef.h

@@ -86,6 +86,8 @@ typedef uint64_t avm_uint64_t;
     #error "term size must be either 32 bit or 64 bit."
 #endif
 
+_Static_assert(SIZE_MAX >= AVM_INT_MAX, "SIZE_MAX < AVM_INT_MAX is an unsupported configuration.");
+
 #define UNICODE_CHAR_MAX 0x10FFFF
 
 #define MIN_NOT_BOXED_INT (AVM_INT_MIN >> 4)