A debug session snippet:
Breakpoint 1, Parrot_invokecc_p (cur_opcode=0x84c7540,
interpreter=0x82a6008) at core.ops:411
411 PMC * p = $1;
(gdb) help user-defined
User-defined commands.
The commands in this class are those defined by the user.
Use the "define" command to define a command.
List of commands:
pi -- Pi n
ps -- Ps n
(gdb) help pi
pi n ... print contents of interpreter register In
(a variable 'interpreter' must be in context)
(gdb) ps 0
S0=0xbffff2f1 "11"
(gdb) ps 1
S1=0x8245113 "no such reg"
(gdb) pi 0
I0=0
(gdb) pi 1
I1=3
