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Diffstat (limited to 'gas/config/tc-i386.c')
-rw-r--r--gas/config/tc-i386.c261
1 files changed, 235 insertions, 26 deletions
diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index 9c99a85..aaca79c 100644
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -323,12 +323,18 @@ static const char *cpu_sub_arch_name = NULL;
/* CPU feature flags. */
static unsigned int cpu_arch_flags = CpuUnknownFlags | CpuNo64;
+/* If we have selected a cpu we are generating instructions for. */
+static int cpu_arch_tune_set = 0;
+
/* Cpu we are generating instructions for. */
static enum processor_type cpu_arch_tune = PROCESSOR_UNKNOWN;
/* CPU feature flags of cpu we are generating instructions for. */
static unsigned int cpu_arch_tune_flags = 0;
+/* CPU instruction set architecture used. */
+static enum processor_type cpu_arch_isa = PROCESSOR_UNKNOWN;
+
/* CPU feature flags of instruction set architecture used. */
static unsigned int cpu_arch_isa_flags = 0;
@@ -562,7 +568,7 @@ i386_align_code (fragP, count)
static const char f32_1[] =
{0x90}; /* nop */
static const char f32_2[] =
- {0x89,0xf6}; /* movl %esi,%esi */
+ {0x66,0x90}; /* xchg %ax,%ax */
static const char f32_3[] =
{0x8d,0x76,0x00}; /* leal 0(%esi),%esi */
static const char f32_4[] =
@@ -622,13 +628,140 @@ i386_align_code (fragP, count)
f32_1, f32_2, f16_3, f16_4, f16_5, f16_6, f16_7, f16_8,
f32_15, f32_15, f32_15, f32_15, f32_15, f32_15, f32_15
};
+ /* nopl (%[re]ax) */
+ static const char alt_3[] =
+ {0x0f,0x1f,0x00};
+ /* nopl 0(%[re]ax) */
+ static const char alt_4[] =
+ {0x0f,0x1f,0x40,0x00};
+ /* nopl 0(%[re]ax,%[re]ax,1) */
+ static const char alt_5[] =
+ {0x0f,0x1f,0x44,0x00,0x00};
+ /* nopw 0(%[re]ax,%[re]ax,1) */
+ static const char alt_6[] =
+ {0x66,0x0f,0x1f,0x44,0x00,0x00};
+ /* nopl 0L(%[re]ax) */
+ static const char alt_7[] =
+ {0x0f,0x1f,0x80,0x00,0x00,0x00,0x00};
+ /* nopl 0L(%[re]ax,%[re]ax,1) */
+ static const char alt_8[] =
+ {0x0f,0x1f,0x84,0x00,0x00,0x00,0x00,0x00};
+ /* nopw 0L(%[re]ax,%[re]ax,1) */
+ static const char alt_9[] =
+ {0x66,0x0f,0x1f,0x84,0x00,0x00,0x00,0x00,0x00};
+ /* nopw %cs:0L(%[re]ax,%[re]ax,1) */
+ static const char alt_10[] =
+ {0x66,0x2e,0x0f,0x1f,0x84,0x00,0x00,0x00,0x00,0x00};
+ /* data16
+ nopw %cs:0L(%[re]ax,%[re]ax,1) */
+ static const char alt_long_11[] =
+ {0x66,
+ 0x66,0x2e,0x0f,0x1f,0x84,0x00,0x00,0x00,0x00,0x00};
+ /* data16
+ data16
+ nopw %cs:0L(%[re]ax,%[re]ax,1) */
+ static const char alt_long_12[] =
+ {0x66,
+ 0x66,
+ 0x66,0x2e,0x0f,0x1f,0x84,0x00,0x00,0x00,0x00,0x00};
+ /* data16
+ data16
+ data16
+ nopw %cs:0L(%[re]ax,%[re]ax,1) */
+ static const char alt_long_13[] =
+ {0x66,
+ 0x66,
+ 0x66,
+ 0x66,0x2e,0x0f,0x1f,0x84,0x00,0x00,0x00,0x00,0x00};
+ /* data16
+ data16
+ data16
+ data16
+ nopw %cs:0L(%[re]ax,%[re]ax,1) */
+ static const char alt_long_14[] =
+ {0x66,
+ 0x66,
+ 0x66,
+ 0x66,
+ 0x66,0x2e,0x0f,0x1f,0x84,0x00,0x00,0x00,0x00,0x00};
+ /* data16
+ data16
+ data16
+ data16
+ data16
+ nopw %cs:0L(%[re]ax,%[re]ax,1) */
+ static const char alt_long_15[] =
+ {0x66,
+ 0x66,
+ 0x66,
+ 0x66,
+ 0x66,
+ 0x66,0x2e,0x0f,0x1f,0x84,0x00,0x00,0x00,0x00,0x00};
+ /* nopl 0(%[re]ax,%[re]ax,1)
+ nopw 0(%[re]ax,%[re]ax,1) */
+ static const char alt_short_11[] =
+ {0x0f,0x1f,0x44,0x00,0x00,
+ 0x66,0x0f,0x1f,0x44,0x00,0x00};
+ /* nopw 0(%[re]ax,%[re]ax,1)
+ nopw 0(%[re]ax,%[re]ax,1) */
+ static const char alt_short_12[] =
+ {0x66,0x0f,0x1f,0x44,0x00,0x00,
+ 0x66,0x0f,0x1f,0x44,0x00,0x00};
+ /* nopw 0(%[re]ax,%[re]ax,1)
+ nopl 0L(%[re]ax) */
+ static const char alt_short_13[] =
+ {0x66,0x0f,0x1f,0x44,0x00,0x00,
+ 0x0f,0x1f,0x80,0x00,0x00,0x00,0x00};
+ /* nopl 0L(%[re]ax)
+ nopl 0L(%[re]ax) */
+ static const char alt_short_14[] =
+ {0x0f,0x1f,0x80,0x00,0x00,0x00,0x00,
+ 0x0f,0x1f,0x80,0x00,0x00,0x00,0x00};
+ /* nopl 0L(%[re]ax)
+ nopl 0L(%[re]ax,%[re]ax,1) */
+ static const char alt_short_15[] =
+ {0x0f,0x1f,0x80,0x00,0x00,0x00,0x00,
+ 0x0f,0x1f,0x84,0x00,0x00,0x00,0x00,0x00};
+ static const char *const alt_short_patt[] = {
+ f32_1, f32_2, alt_3, alt_4, alt_5, alt_6, alt_7, alt_8,
+ alt_9, alt_10, alt_short_11, alt_short_12, alt_short_13,
+ alt_short_14, alt_short_15
+ };
+ static const char *const alt_long_patt[] = {
+ f32_1, f32_2, alt_3, alt_4, alt_5, alt_6, alt_7, alt_8,
+ alt_9, alt_10, alt_long_11, alt_long_12, alt_long_13,
+ alt_long_14, alt_long_15
+ };
if (count <= 0 || count > 15)
return;
- /* The recommended way to pad 64bit code is to use NOPs preceded by
- maximally four 0x66 prefixes. Balance the size of nops. */
- if (flag_code == CODE_64BIT)
+ /* We need to decide which NOP sequence to use for 32bit and
+ 64bit. When -mtune= is used:
+
+ 1. For PROCESSOR_I486, PROCESSOR_PENTIUM and PROCESSOR_GENERIC32,
+ f32_patt will be used.
+ 2. For PROCESSOR_K8 in 64bit, NOPs with 0x66 prefixe will be used.
+ 3. For PROCESSOR_MEROM, alt_long_patt will be used.
+ 4. For PROCESSOR_PENTIUMPRO, PROCESSOR_PENTIUM4, PROCESSOR_NOCONA,
+ PROCESSOR_YONAH, PROCESSOR_MEROM, PROCESSOR_K6, PROCESSOR_ATHLON
+ and PROCESSOR_GENERIC64, alt_short_patt will be used.
+
+ When -mtune= isn't used, alt_short_patt will be used if
+ cpu_arch_isa_flags has Cpu686. Otherwise, f32_patt will be used.
+
+ When -march= or .arch is used, we can't use anything beyond
+ cpu_arch_isa_flags. */
+
+ if (flag_code == CODE_16BIT)
+ {
+ memcpy (fragP->fr_literal + fragP->fr_fix,
+ f16_patt[count - 1], count);
+ if (count > 8)
+ /* Adjust jump offset. */
+ fragP->fr_literal[fragP->fr_fix + 1] = count - 2;
+ }
+ else if (flag_code == CODE_64BIT && cpu_arch_tune == PROCESSOR_K8)
{
int i;
int nnops = (count + 3) / 4;
@@ -636,6 +769,8 @@ i386_align_code (fragP, count)
int remains = count - nnops * len;
int pos = 0;
+ /* The recommended way to pad 64bit code is to use NOPs preceded
+ by maximally four 0x66 prefixes. Balance the size of nops. */
for (i = 0; i < remains; i++)
{
memset (fragP->fr_literal + fragP->fr_fix + pos, 0x66, len);
@@ -650,17 +785,84 @@ i386_align_code (fragP, count)
}
}
else
- if (flag_code == CODE_16BIT)
- {
- memcpy (fragP->fr_literal + fragP->fr_fix,
- f16_patt[count - 1], count);
- if (count > 8)
- /* Adjust jump offset. */
- fragP->fr_literal[fragP->fr_fix + 1] = count - 2;
- }
- else
+ {
+ const char *const *patt = NULL;
+
+ if (cpu_arch_isa == PROCESSOR_UNKNOWN)
+ {
+ /* PROCESSOR_UNKNOWN means that all ISAs may be used. */
+ switch (cpu_arch_tune)
+ {
+ case PROCESSOR_UNKNOWN:
+ /* We use cpu_arch_isa_flags to check if we SHOULD
+ optimize for Cpu686. */
+ if ((cpu_arch_isa_flags & Cpu686) != 0)
+ patt = alt_short_patt;
+ else
+ patt = f32_patt;
+ break;
+ case PROCESSOR_MEROM:
+ patt = alt_long_patt;
+ break;
+ case PROCESSOR_PENTIUMPRO:
+ case PROCESSOR_PENTIUM4:
+ case PROCESSOR_NOCONA:
+ case PROCESSOR_YONAH:
+ case PROCESSOR_K6:
+ case PROCESSOR_ATHLON:
+ case PROCESSOR_K8:
+ case PROCESSOR_GENERIC64:
+ patt = alt_short_patt;
+ break;
+ case PROCESSOR_I486:
+ case PROCESSOR_PENTIUM:
+ case PROCESSOR_GENERIC32:
+ patt = f32_patt;
+ break;
+ }
+ }
+ else
+ {
+ switch (cpu_arch_tune)
+ {
+ case PROCESSOR_UNKNOWN:
+ /* When cpu_arch_isa is net, cpu_arch_tune shouldn't be
+ PROCESSOR_UNKNOWN. */
+ abort ();
+ break;
+
+ case PROCESSOR_I486:
+ case PROCESSOR_PENTIUM:
+ case PROCESSOR_PENTIUMPRO:
+ case PROCESSOR_PENTIUM4:
+ case PROCESSOR_NOCONA:
+ case PROCESSOR_YONAH:
+ case PROCESSOR_K6:
+ case PROCESSOR_ATHLON:
+ case PROCESSOR_K8:
+ case PROCESSOR_GENERIC32:
+ /* We use cpu_arch_isa_flags to check if we CAN optimize
+ for Cpu686. */
+ if ((cpu_arch_isa_flags & Cpu686) != 0)
+ patt = alt_short_patt;
+ else
+ patt = f32_patt;
+ break;
+ case PROCESSOR_MEROM:
+ if ((cpu_arch_isa_flags & Cpu686) != 0)
+ patt = alt_long_patt;
+ else
+ patt = f32_patt;
+ break;
+ case PROCESSOR_GENERIC64:
+ patt = alt_short_patt;
+ break;
+ }
+ }
+
memcpy (fragP->fr_literal + fragP->fr_fix,
- f32_patt[count - 1], count);
+ patt[count - 1], count);
+ }
fragP->fr_var = count;
}
@@ -937,7 +1139,13 @@ set_cpu_arch (dummy)
cpu_sub_arch_name = NULL;
cpu_arch_flags = (cpu_arch[i].flags
| (flag_code == CODE_64BIT ? Cpu64 : CpuNo64));
+ cpu_arch_isa = cpu_arch[i].type;
cpu_arch_isa_flags = cpu_arch[i].flags;
+ if (!cpu_arch_tune_set)
+ {
+ cpu_arch_tune = cpu_arch_isa;
+ cpu_arch_tune_flags = cpu_arch_isa_flags;
+ }
break;
}
if ((cpu_arch_flags | cpu_arch[i].flags) != cpu_arch_flags)
@@ -5587,7 +5795,13 @@ md_parse_option (int c, char *arg)
{
if (strcmp (arg, cpu_arch [i].name) == 0)
{
+ cpu_arch_isa = cpu_arch[i].type;
cpu_arch_isa_flags = cpu_arch[i].flags;
+ if (!cpu_arch_tune_set)
+ {
+ cpu_arch_tune = cpu_arch_isa;
+ cpu_arch_tune_flags = cpu_arch_isa_flags;
+ }
break;
}
}
@@ -5602,6 +5816,7 @@ md_parse_option (int c, char *arg)
{
if (strcmp (arg, cpu_arch [i].name) == 0)
{
+ cpu_arch_tune_set = 1;
cpu_arch_tune = cpu_arch [i].type;
cpu_arch_tune_flags = cpu_arch[i].flags;
break;
@@ -5663,24 +5878,18 @@ i386_target_format ()
cpu_arch_isa_flags = Cpu086|Cpu186|Cpu286|Cpu386|Cpu486
|Cpu586|Cpu686|CpuP4|CpuMMX|CpuMMX2
|CpuSSE|CpuSSE2;
- if (cpu_arch_tune == PROCESSOR_UNKNOWN)
- {
- cpu_arch_tune = PROCESSOR_GENERIC64;
- cpu_arch_tune_flags = Cpu086|Cpu186|Cpu286|Cpu386|Cpu486
- |Cpu586|Cpu686|CpuP4|CpuMMX|CpuMMX2
- |CpuSSE|CpuSSE2;
- }
+ if (cpu_arch_tune_flags == 0)
+ cpu_arch_tune_flags = Cpu086|Cpu186|Cpu286|Cpu386|Cpu486
+ |Cpu586|Cpu686|CpuP4|CpuMMX|CpuMMX2
+ |CpuSSE|CpuSSE2;
}
else if (!strcmp (default_arch, "i386"))
{
set_code_flag (CODE_32BIT);
if (cpu_arch_isa_flags == 0)
cpu_arch_isa_flags = Cpu086|Cpu186|Cpu286|Cpu386;
- if (cpu_arch_tune == PROCESSOR_UNKNOWN)
- {
- cpu_arch_tune = PROCESSOR_GENERIC32;
- cpu_arch_tune_flags = Cpu086|Cpu186|Cpu286|Cpu386;
- }
+ if (cpu_arch_tune_flags == 0)
+ cpu_arch_tune_flags = Cpu086|Cpu186|Cpu286|Cpu386;
}
else
as_fatal (_("Unknown architecture"));
generated by cgit v1.1 at 2024-12-05 02:35:30 +0000