Next: Looking Up an Existing Architecture, Up: Initialize New Architecture

#### 11.2.1 How an Architecture is Represented

Each `gdbarch` is associated with a single bfd architecture, via a `bfd_arch_`arch in the `bfd_architecture` enumeration. The `gdbarch` is registered by a call to `register_gdbarch_init`, usually from the file's `_initialize_`filename routine, which will be automatically called during gdb startup. The arguments are a bfd architecture constant and an initialization function.

A gdb description for a new architecture, arch is created by defining a global function `_initialize_`arch`_tdep`, by convention in the source file `arch-tdep.c`. For example, in the case of the OpenRISC 1000, this function is called `_initialize_or1k_tdep` and is found in the file `or1k-tdep.c`.

The resulting object files containing the implementation of the `_initialize_`arch`_tdep` function are specified in the gdb `configure.tgt` file, which includes a large case statement pattern matching against the `--target` option of the `configure` script. The new `struct gdbarch` is created within the `_initialize_`arch`_tdep` function by calling `gdbarch_register`:

         void gdbarch_register (enum bfd_architecture    architecture,
                                gdbarch_init_ftype      *init_func,
                                gdbarch_dump_tdep_ftype *tdep_dump_func);

The architecture will identify the unique bfd to be associated with this `gdbarch`. The init_func funciton is called to create and return the new `struct gdbarch`. The tdep_dump_func function will dump the target specific details associated with this architecture.

For example the function `_initialize_or1k_tdep` creates its architecture for 32-bit OpenRISC 1000 architectures by calling:

         gdbarch_register (bfd_arch_or32, or1k_gdbarch_init, or1k_dump_tdep);