target/arm: Convert load/store exclusive and ordered to decodetree

Convert the instructions in the load/store exclusive (STXR,
STLXR, LDXR, LDAXR) and load/store ordered (STLR, STLLR,
LDAR, LDLAR) to decodetree.

Note that for STLR, STLLR, LDAR, LDLAR this fixes an under-decoding
in the legacy decoder where we were not checking that the RES1 bits
in the Rs and Rt2 fields were set.

The new function ldst_iss_sf() is equivalent to the existing
disas_ldst_compute_iss_sf(), but it takes the pre-decoded 'ext' field
rather than taking an undecoded two-bit opc field and extracting
'ext' from it. Once all the loads and stores have been converted
to decodetree disas_ldst_compute_iss_sf() will be unused and
can be deleted.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20230602155223.2040685-9-peter.maydell@linaro.org
2 files changed