at_breakpoint
bp = at_breakpoint(a);
static struct bpt *at_breakpoint(unsigned long pc);
bp = at_breakpoint(regs->nip);
bp = at_breakpoint(regs->nip);
bp = at_breakpoint(regs->nip);
bp = at_breakpoint(regs->nip);
bp = at_breakpoint(regs->nip);
bp = at_breakpoint(a);
bp2 = at_breakpoint(bp->address - 4);