The ‘org.gnu.gdb.s390.core’ feature is required for S/390 and System z targets. It should contain the PSW and the 16 general registers. In particular, System z targets should provide the 64-bit registers ‘pswm’, ‘pswa’, and ‘r0’ through ‘r15’. S/390 targets should provide the 32-bit versions of these registers. A System z target that runs in 31-bit addressing mode should provide 32-bit versions of ‘pswm’ and ‘pswa’, as well as the general register's upper halves ‘r0h’ through ‘r15h’, and their lower halves ‘r0l’ through ‘r15l’.
The ‘org.gnu.gdb.s390.fpr’ feature is required. It should contain the 64-bit registers ‘f0’ through ‘f15’, and ‘fpc’.
The ‘org.gnu.gdb.s390.acr’ feature is required. It should contain the 32-bit registers ‘acr0’ through ‘acr15’.
The ‘org.gnu.gdb.s390.linux’ feature is optional. It should contain the register ‘orig_r2’, which is 64-bit wide on System z targets and 32-bit otherwise. In addition, the feature may contain the ‘last_break’ register, whose width depends on the addressing mode, as well as the ‘system_call’ register, which is always 32-bit wide.
The ‘org.gnu.gdb.s390.tdb’ feature is optional. It should contain the 64-bit registers ‘tdb0’, ‘tac’, ‘tct’, ‘atia’, and ‘tr0’ through ‘tr15’.
The ‘org.gnu.gdb.s390.vx’ feature is optional. It should contain 64-bit wide registers ‘v0l’ through ‘v15l’, which will be combined by gdb with the floating point registers ‘f0’ through ‘f15’ to present the 128-bit wide vector registers ‘v0’ through ‘v15’. In addition, this feature should contain the 128-bit wide vector registers ‘v16’ through ‘v31’.
The ‘org.gnu.gdb.s390.gs’ feature is optional. It should contain the 64-bit wide guarded-storage-control registers ‘gsd’, ‘gssm’, and ‘gsepla’.
The ‘org.gnu.gdb.s390.gsbc’ feature is optional. It should contain the 64-bit wide guarded-storage broadcast control registers ‘bc_gsd’, ‘bc_gssm’, and ‘bc_gsepla’.