[patch, arm] Use cached dsc->is_thumb instead of re-computing

[Ulrich Weigand]

Yao Qi wrote:

> During writing thumb displaced stepping, we find that displaced_read_reg
> can be refactored to avoid calling displaced_in_arm_mode every time.

Hmm, you now pass *both* DSC and FROM -- the latter is actually redundant
now, since every caller must pass in dsc->insn_addr as FROM anyway ...

Can you update the patch to pass DSC *instead of* FROM, and use
dsc->insn_addr internally?

Thanks,
Ulrich

-- 
  Dr. Ulrich Weigand
  GNU Toolchain for Linux on System z and Cell BE
  Ulrich.Weigand@de.ibm.com