G.4.1 ARM Features
For M-profile targets (e.g. Cortex-M3), the org.gnu.gdb.arm.core feature is replaced by org.gnu.gdb.arm.m-profile. It should contain registers r0 through r13, sp, lr, pc, and xpsr.
The org.gnu.gdb.arm.fpa feature is optional. If present, it should contain registers f0 through f7 and fps.
The org.gnu.gdb.xscale.iwmmxt feature is optional. If present, it should contain at least registers wR0 through wR15 and wCGR0 through wCGR3. The wCID, wCon, wCSSF, and wCASF registers are optional.
The org.gnu.gdb.arm.vfp feature is optional. If present, it should contain at least registers d0 through d15. If they are present, d16 through d31 should also be included. gdb will synthesize the single-precision registers from halves of the double-precision registers.
The org.gnu.gdb.arm.neon feature is optional. It does not need to contain registers; it instructs gdb to display the VFP double-precision registers as vectors and to synthesize the quad-precision registers from pairs of double-precision registers. If this feature is present, org.gnu.gdb.arm.vfp must also be present and include 32 double-precision registers.