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Workaround for Itanium A/B step errata

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Bernd Schmidt 2000-11-15 17:34:00 +00:00
parent 79496e2fad
commit 88be23ec6a
2 changed files with 124 additions and 0 deletions
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7
gas/ChangeLog
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@ -1,3 +1,10 @@
2000-11-15 Bernd Schmidt <bernds@redhat.com>
* tc-ia64.c (struct md): New entries LAST_GROUPS, GROUP_IDX.
(errata_nops_necessary_p): New function.
(emit_one_bundle): Call it. Update the GROUP_IDX field in struct
md.
2000-11-14 Jim Wilson <wilson@redhat.com>
* config/tc-ia64.c (ia64_target_format): If EF_IA_64_BE not set, then

117
gas/config/tc-ia64.c
View file

@ -252,6 +252,25 @@ static struct
the current DV-checking block. */
int maxpaths; /* size currently allocated for
entry_labels */
/* Support for hardware errata workarounds. */
/* Record data about the last three insn groups. */
struct group
{
/* B-step workaround.
For each predicate register, this is set if the corresponding insn
group conditionally sets this register with one of the affected
instructions. */
int p_reg_set[64];
/* B-step workaround.
For each general register, this is set if the corresponding insn
a) is conditional one one of the predicate registers for which
P_REG_SET is 1 in the corresponding entry of the previous group,
b) sets this general register with one of the affected
instructions. */
int g_reg_set_conditionally[128];
} last_groups[3];
int group_idx;
}
md;
@ -5159,6 +5178,95 @@ parse_operands (idesc)
return idesc;
}
/* Keep track of state necessary to determine whether a NOP is necessary
to avoid an erratum in A and B step Itanium chips, and return 1 if we
detect a case where additional NOPs may be necessary. */
static int
errata_nop_necessary_p (slot, insn_unit)
struct slot *slot;
enum ia64_unit insn_unit;
{
int i;
struct group *this_group = md.last_groups + md.group_idx;
struct group *prev_group = md.last_groups + (md.group_idx + 2) % 3;
struct ia64_opcode *idesc = slot->idesc;
/* Test whether this could be the first insn in a problematic sequence. */
if (insn_unit == IA64_UNIT_F)
{
for (i = 0; i < idesc->num_outputs; i++)
if (idesc->operands[i] == IA64_OPND_P1
|| idesc->operands[i] == IA64_OPND_P2)
{
int regno = slot->opnd[i].X_add_number - REG_P;
if (regno > 16)
abort ();
this_group->p_reg_set[regno] = 1;
}
}
/* Test whether this could be the second insn in a problematic sequence. */
if (insn_unit == IA64_UNIT_M && slot->qp_regno > 0
&& prev_group->p_reg_set[slot->qp_regno])
{
for (i = 0; i < idesc->num_outputs; i++)
if (idesc->operands[i] == IA64_OPND_R1
|| idesc->operands[i] == IA64_OPND_R2
|| idesc->operands[i] == IA64_OPND_R3)
{
int regno = slot->opnd[i].X_add_number - REG_GR;
if (regno > 128)
abort ();
if (strncmp (idesc->name, "add", 3) != 0
&& strncmp (idesc->name, "sub", 3) != 0
&& strncmp (idesc->name, "shladd", 6) != 0
&& (idesc->flags & IA64_OPCODE_POSTINC) == 0)
this_group->g_reg_set_conditionally[regno] = 1;
}
}
/* Test whether this could be the third insn in a problematic sequence. */
for (i = 0; i < NELEMS (idesc->operands) && idesc->operands[i]; i++)
{
if (/* For fc, ptc, ptr, tak, thash, tpa, ttag, probe, ptr, ptc. */
idesc->operands[i] == IA64_OPND_R3
/* For mov indirect. */
|| idesc->operands[i] == IA64_OPND_RR_R3
|| idesc->operands[i] == IA64_OPND_DBR_R3
|| idesc->operands[i] == IA64_OPND_IBR_R3
|| idesc->operands[i] == IA64_OPND_PKR_R3
|| idesc->operands[i] == IA64_OPND_PMC_R3
|| idesc->operands[i] == IA64_OPND_PMD_R3
|| idesc->operands[i] == IA64_OPND_MSR_R3
|| idesc->operands[i] == IA64_OPND_CPUID_R3
/* For itr. */
|| idesc->operands[i] == IA64_OPND_ITR_R3
|| idesc->operands[i] == IA64_OPND_DTR_R3
/* Normal memory addresses (load, store, xchg, cmpxchg, etc.). */
|| idesc->operands[i] == IA64_OPND_MR3)
{
int regno = slot->opnd[i].X_add_number - REG_GR;
if (regno > 128)
abort ();
if (idesc->operands[i] == IA64_OPND_R3)
{
if (strcmp (idesc->name, "fc") != 0
&& strcmp (idesc->name, "tak") != 0
&& strcmp (idesc->name, "thash") != 0
&& strcmp (idesc->name, "tpa") != 0
&& strcmp (idesc->name, "ttag") != 0
&& strncmp (idesc->name, "ptr", 3) != 0
&& strncmp (idesc->name, "ptc", 3) != 0
&& strncmp (idesc->name, "probe", 5) != 0)
return 0;
}
if (prev_group->g_reg_set_conditionally[regno])
return 1;
}
}
return 0;
}
static void
build_insn (slot, insnp)
struct slot *slot;
@ -5549,6 +5657,9 @@ emit_one_bundle ()
dwarf2_gen_line_info (addr, &md.slot[curr].debug_line);
}
if (errata_nop_necessary_p (md.slot + curr, insn_unit))
as_warn (_("Additional NOP may be necessary to workaround Itanium processor A/B step errata"));
build_insn (md.slot + curr, insn + i);
/* Set slot counts for non prologue/body unwind records. */
@ -5595,6 +5706,12 @@ emit_one_bundle ()
end_of_insn_group = md.slot[curr].end_of_insn_group;
if (end_of_insn_group)
{
md.group_idx = (md.group_idx + 1) % 3;
memset (md.last_groups + md.group_idx, 0, sizeof md.last_groups[0]);
}
/* clear slot: */
ia64_free_opcode (md.slot[curr].idesc);
memset (md.slot + curr, 0, sizeof (md.slot[curr]));