include/exec/memop.h

7  * This work is licensed under the terms of the GNU GPL, version 2 or later.
8  * See the COPYING file in the top-level directory.
15 #include "qemu/host-utils.h"
28     MO_SIGN  = 0x08,   /* Sign-extended, otherwise zero-extended.  */
52      * to a size more than the size of the memory access.
56      * MO_ALIGN supposes the alignment size is the size of a memory access.
59      * - unaligned access permitted (MO_UNALN).
60      * - an alignment to the size of an access (MO_ALIGN);
61      * - an alignment to a specified size, which may be more or less than
76      * MO_ATOM_* describes the atomicity requirements of the operation:
77      * MO_ATOM_IFALIGN: the operation must be single-copy atomic if it
80      *    be a pair of half-sized operations which are packed together
81      *    for convenience, with single-copy atomicity on each half if
83      *    This is the atomicity e.g. of Arm pre-FEAT_LSE2 LDP.
84      * MO_ATOM_WITHIN16: the operation is single-copy atomic, even if it
85      *    is unaligned, so long as it does not cross a 16-byte boundary;
86      *    if it crosses a 16-byte boundary there is no atomicity.
87      *    This is the atomicity e.g. of Arm FEAT_LSE2 LDR.
88      * MO_ATOM_WITHIN16_PAIR: the entire operation is single-copy atomic,
89      *    if it happens to be within a 16-byte boundary, otherwise it
90      *    devolves to a pair of half-sized MO_ATOM_WITHIN16 operations.
91      *    Depending on alignment, one or both will be single-copy atomic.
92      *    This is the atomicity e.g. of Arm FEAT_LSE2 LDP.
93      * MO_ATOM_SUBALIGN: the operation is single-copy atomic by parts
94      *    by the alignment.  E.g. if an 8-byte value is accessed at an
95      *    address which is 0 mod 8, then the whole 8-byte access is
96      *    single-copy atomic; otherwise, if it is accessed at 0 mod 4
97      *    then each 4-byte subobject is single-copy atomic; otherwise
98      *    if it is accessed at 0 mod 2 then the four 2-byte subobjects
99      *    are single-copy atomic.
100      *    This is the atomicity e.g. of IBM Power.
103      * Note the default (i.e. 0) value is single-copy atomic to the
104      * size of the operation, if aligned.  This retains the behaviour
116     /* Combinations of the above, for ease of use.  */
165     /* Power of 2 up to 8.  */  in size_memop()
166     assert((size & (size - 1)) == 0 && size >= 1 && size <= 8);  in size_memop()
210         size = size ? size - 1 : 0;  in memop_atomicity_bits()