static sim_cia
step_once (SIM_CPU *cpu)
{
SIM_DESC sd = CPU_STATE (cpu);
bu32 insn_len, oldpc = PCREG;
int i;
bool ssstep;
if (TRACE_ANY_P (cpu))
trace_prefix (sd, cpu, NULL_CIA, oldpc, TRACE_LINENUM_P (cpu),
NULL, 0, " "); /* Use a space for gcc warnings. */
/* Handle hardware single stepping when lower than EVT3, and when SYSCFG
has already had the SSSTEP bit enabled. */
ssstep = false;
if (STATE_ENVIRONMENT (sd) == OPERATING_ENVIRONMENT
&& (SYSCFGREG & SYSCFG_SSSTEP))
{
int ivg = cec_get_ivg (cpu);
if (ivg == -1 || ivg > 3)
ssstep = true;
}
#if 0
/* XXX: Is this what happens on the hardware ? */
if (cec_get_ivg (cpu) == EVT_EMU)
cec_return (cpu, EVT_EMU);
#endif
BFIN_CPU_STATE.did_jump = false;
insn_len = interp_insn_bfin (cpu, oldpc);
/* If we executed this insn successfully, then we always decrement
the loop counter. We don't want to update the PC though if the
last insn happened to be a change in code flow (jump/etc...). */
if (!BFIN_CPU_STATE.did_jump)
SET_PCREG (hwloop_get_next_pc (cpu, oldpc, insn_len));
for (i = 1; i >= 0; --i)
if (LCREG (i) && oldpc == LBREG (i))
{
SET_LCREG (i, LCREG (i) - 1);
if (LCREG (i))
break;
}
++ PROFILE_TOTAL_INSN_COUNT (CPU_PROFILE_DATA (cpu));
/* Handle hardware single stepping only if we're still lower than EVT3.
XXX: May not be entirely correct wrt EXCPT insns. */
if (ssstep)
{
int ivg = cec_get_ivg (cpu);
if (ivg == -1 || ivg > 3)
{
INSN_LEN = 0;
cec_exception (cpu, VEC_STEP);
}
}
return oldpc;
}
void
cec_exception (SIM_CPU *cpu, int excp)
{
SIM_DESC sd = CPU_STATE (cpu);
int sigrc = -1;
TRACE_EVENTS (cpu, "processing exception %#x in EVT%i", excp,
cec_get_ivg (cpu));
/* Ideally what would happen here for real hardware exceptions (not
fake sim ones) is that:
- For service exceptions (excp <= 0x11):
RETX is the _next_ PC which can be tricky with jumps/hardware loops/...
- For error exceptions (excp > 0x11):
RETX is the _current_ PC (i.e. the one causing the exception)
- PC is loaded with EVT3 MMR
- ILAT/IPEND in CEC is updated depending on current IVG level
- the fault address MMRs get updated with data/instruction info
- Execution continues on in the EVT3 handler */
/* Handle simulator exceptions first. */
switch (excp)
{
case VEC_SIM_HLT:
excp_to_sim_halt (sim_exited, 0);
return;
case VEC_SIM_ABORT:
excp_to_sim_halt (sim_exited, 1);
return;
case VEC_SIM_TRAP:
/* GDB expects us to step over EMUEXCPT. */
/* XXX: What about hwloops and EMUEXCPT at the end?
Pretty sure gdb doesn't handle this already... */
SET_PCREG (PCREG + 2);
/* Only trap when we are running in gdb. */
if (STATE_OPEN_KIND (sd) == SIM_OPEN_DEBUG)
excp_to_sim_halt (sim_stopped, SIM_SIGTRAP);
return;
case VEC_SIM_DBGA:
/* If running in gdb, simply trap. */
if (STATE_OPEN_KIND (sd) == SIM_OPEN_DEBUG)
excp_to_sim_halt (sim_stopped, SIM_SIGTRAP);
else
excp_to_sim_halt (sim_exited, 2);
}
if (excp <= 0x3f)
{
SET_EXCAUSE (excp);
if (STATE_ENVIRONMENT (sd) == OPERATING_ENVIRONMENT)
{
/* ICPLB regs always get updated. */
/* XXX: Should optimize this call path ... */
if (excp != VEC_MISALI_I && excp != VEC_MISALI_D
&& excp != VEC_CPLB_I_M && excp != VEC_CPLB_M
&& excp != VEC_CPLB_I_VL && excp != VEC_CPLB_VL
&& excp != VEC_CPLB_I_MHIT && excp != VEC_CPLB_MHIT)
mmu_log_ifault (cpu);
_cec_raise (cpu, CEC_STATE (cpu), IVG_EVX);
/* We need to restart the engine so that we don't return
and continue processing this bad insn. */
if (EXCAUSE >= 0x20)
sim_engine_restart (sd, cpu, NULL, PCREG);
return;
}
}
TRACE_EVENTS (cpu, "running virtual exception handler");
switch (excp)
{
case VEC_SYS:
bfin_syscall (cpu);
break;
case VEC_EXCPT01: /* Userspace gdb breakpoint. */
sigrc = SIM_SIGTRAP;
break;
case VEC_UNDEF_I: /* Undefined instruction. */
sigrc = SIM_SIGILL;
break;
case VEC_ILL_RES: /* Illegal supervisor resource. */
case VEC_MISALI_I: /* Misaligned instruction. */
sigrc = SIM_SIGBUS;
break;
case VEC_CPLB_M:
case VEC_CPLB_I_M:
sigrc = SIM_SIGSEGV;
break;
default:
sim_io_eprintf (sd, "Unhandled exception %#x at 0x%08x (%s)\n",
excp, PCREG, excp_decoded[excp]);
sigrc = SIM_SIGILL;
break;
}
if (sigrc != -1)
excp_to_sim_halt (sim_stopped, sigrc);
}