The step packet (s) requests a single machine instruction step. Its implementation is almost identical to that of the continue (c) packet, but using the functions rsp_step () and rsp_step_generic ().

The sole difference is that the generic function sets, rather than clears the single stepping flag in Debug Mode Register 1. This ensures a TRAP exception is raised after the next instruction completes execution.

  cpu_state.sprs[SPR_DRR]   = 0;
  cpu_state.sprs[SPR_DMR2] &= ~SPR_DMR2_WGB;
  cpu_state.sprs[SPR_DMR1] |= SPR_DMR1_ST;
  cpu_state.sprs[SPR_DSR]  |= SPR_DSR_TE;