STINNER Victor added the comment: Demur: "This patch [ ushort.patch ] seeks to be a minimal change to achieve the desired aligned/batched memory read behavior of NEXTOP/NEXTARG."
We are concerned by undefined behaviours in CPython for portability reasons. Using a "unsigned short*" pointer avoids the undefined behaviour. I'm talking about unsigned char* => unsigned short* conversion followed by a dereference: +#define NEXTOPARG() (oparg = *(unsigned short*)next_instr, opcode = OPOF(oparg), oparg = ARGOF(oparg), next_instr += 2) With ushort2.patch, the risk is reduced at once place which is now "protected" by an assertion: + assert(_Py_IS_ALIGNED(PyBytes_AS_STRING(co->co_code), unsigned short)); + first_instr = (unsigned short*) PyBytes_AS_STRING(co->co_code); ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue27097> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
