* regcache.c (registers_changed, registers_fetched): Use
ARCH_NUM_REGS directly, eliminating an unnecessary variable.
This change adds pseudo-register capability to GDB.
Pseudo-registers are handled like registers, but they
don't come from or live on the target. They may be
aliases for an existing register, or they may be computed.
* defs.h (NUM_PSEUDO_REGISTERS): Define default of zero.
(ARCH_FETCH_PSEUDO_REGISTERS): Define default of no-op.
(ARCH_STORE_PSEUDO_REGISTERS): Define default of no-op.
# regcache.c (registers_changed): Mark pseudo-registers
invalid, as well as real registers.
(registers_fetched): Do not mark pseudo-registers as fetched
at the same time as other (real) registers.
(read_register_bytes): Fetch pseudo-registers (if any) from
the target architecture module instead of from the target.
(read_register_gen): Ditto.
(read_register): Ditto.
(write_register_bytes): Store pseudo-registers (if any) to
the target architecture module instead of to the target.
(write_register_gen): Ditto.
(write_register): Ditto.
(build_regcache): Allocate enough register_valid space for
pseudo-registers as well as normal (real) ones.
