unicorn/qemu/target
Peter Maydell ddfe550411
arm: Thumb shift operations should not permit interworking branches
In Thumb mode, the only instructions which can cause an interworking
branch by writing the PC are BLX, BX, BXJ, LDR, POP and LDM. Unlike
ARM mode, data processing instructions which target the PC do not
cause interworking branches.

When we added support for doing interworking branches on writes to
PC from data processing instructions in commit 21aeb3430ce7ba, we
accidentally changed a Thumb instruction to have interworking
branch behaviour for writes to PC. (MOV, MOVS register-shifted
register, encoding T2; this is the standard encoding for
LSL/LSR/ASR/ROR (register).)

For this encoding, behaviour with Rd == R15 is specified as
UNPREDICTABLE, so allowing an interworking branch is within
spec, but it's confusing and differs from our handling of this
class of UNPREDICTABLE for other Thumb ALU operations. Make
it perform a simple (non-interworking) branch like the others.

Backports commit bedb8a6b09c1754c3b9f155750c62dc087706698 from qemu
2018-03-02 14:42:40 -05:00
..
arm arm: Thumb shift operations should not permit interworking branches 2018-03-02 14:42:40 -05:00
i386 i386: Don't override -cpu options on -cpu host/max 2018-03-02 14:22:45 -05:00
m68k Move target-* CPU file into a target/ folder 2018-03-01 22:50:58 -05:00
mips target/mips: fix delay slot detection in gen_msa_branch() 2018-03-02 14:15:50 -05:00
sparc cputlb and arm/sparc targets: convert mmuidx flushes from varg to bitmap 2018-03-02 10:12:40 -05:00