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Optimize alignment routine for x86 & x86_64.

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This commit is contained in:
gbeauche 2006-07-09 15:18:08 +00:00
parent d75a91497d
commit a5296875f1
2 changed files with 93 additions and 8 deletions
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93
SheepShaver/src/kpx_cpu/src/cpu/jit/basic-dyngen.cpp
View File

@ -78,3 +78,96 @@ DEFINE_INVOKE(CPU_im_im, (void (*func)(dyngen_cpu_base, uint32, uint32), uint32
DEFINE_INVOKE(CPU_A0_ret_A0, (void *(*func)(dyngen_cpu_base)), (funcptr));
#undef DEFINE_INVOKE
uint8 *
basic_dyngen::gen_align(int align)
{
int nbytes = align - (((uintptr)code_ptr()) % align);
if (nbytes == 0)
return code_ptr();
#if defined(__i386__) || defined(__x86_64__)
/* Source: GNU Binutils 2.12.90.0.15 */
/* Various efficient no-op patterns for aligning code labels.
Note: Don't try to assemble the instructions in the comments.
0L and 0w are not legal. */
static const uint8 f32_1[] =
{0x90}; /* nop */
static const uint8 f32_2[] =
{0x89,0xf6}; /* movl %esi,%esi */
static const uint8 f32_3[] =
{0x8d,0x76,0x00}; /* leal 0(%esi),%esi */
static const uint8 f32_4[] =
{0x8d,0x74,0x26,0x00}; /* leal 0(%esi,1),%esi */
static const uint8 f32_5[] =
{0x90, /* nop */
0x8d,0x74,0x26,0x00}; /* leal 0(%esi,1),%esi */
static const uint8 f32_6[] =
{0x8d,0xb6,0x00,0x00,0x00,0x00}; /* leal 0L(%esi),%esi */
static const uint8 f32_7[] =
{0x8d,0xb4,0x26,0x00,0x00,0x00,0x00}; /* leal 0L(%esi,1),%esi */
static const uint8 f32_8[] =
{0x90, /* nop */
0x8d,0xb4,0x26,0x00,0x00,0x00,0x00}; /* leal 0L(%esi,1),%esi */
static const uint8 f32_9[] =
{0x89,0xf6, /* movl %esi,%esi */
0x8d,0xbc,0x27,0x00,0x00,0x00,0x00}; /* leal 0L(%edi,1),%edi */
static const uint8 f32_10[] =
{0x8d,0x76,0x00, /* leal 0(%esi),%esi */
0x8d,0xbc,0x27,0x00,0x00,0x00,0x00}; /* leal 0L(%edi,1),%edi */
static const uint8 f32_11[] =
{0x8d,0x74,0x26,0x00, /* leal 0(%esi,1),%esi */
0x8d,0xbc,0x27,0x00,0x00,0x00,0x00}; /* leal 0L(%edi,1),%edi */
static const uint8 f32_12[] =
{0x8d,0xb6,0x00,0x00,0x00,0x00, /* leal 0L(%esi),%esi */
0x8d,0xbf,0x00,0x00,0x00,0x00}; /* leal 0L(%edi),%edi */
static const uint8 f32_13[] =
{0x8d,0xb6,0x00,0x00,0x00,0x00, /* leal 0L(%esi),%esi */
0x8d,0xbc,0x27,0x00,0x00,0x00,0x00}; /* leal 0L(%edi,1),%edi */
static const uint8 f32_14[] =
{0x8d,0xb4,0x26,0x00,0x00,0x00,0x00, /* leal 0L(%esi,1),%esi */
0x8d,0xbc,0x27,0x00,0x00,0x00,0x00}; /* leal 0L(%edi,1),%edi */
static const uint8 f32_15[] =
{0xeb,0x0d,0x90,0x90,0x90,0x90,0x90, /* jmp .+15; lotsa nops */
0x90,0x90,0x90,0x90,0x90,0x90,0x90,0x90};
static const uint8 f32_16[] =
{0xeb,0x0d,0x90,0x90,0x90,0x90,0x90, /* jmp .+15; lotsa nops */
0x90,0x90,0x90,0x90,0x90,0x90,0x90,0x90,0x90};
static const uint8 *const f32_patt[] = {
f32_1, f32_2, f32_3, f32_4, f32_5, f32_6, f32_7, f32_8,
f32_9, f32_10, f32_11, f32_12, f32_13, f32_14, f32_15
};
static const uint8 prefixes[4] = { 0x66, 0x66, 0x66, 0x66 };
#if defined(__x86_64__)
/* The recommended way to pad 64bit code is to use NOPs preceded by
maximally four 0x66 prefixes. Balance the size of nops. */
int i;
int nnops = (nbytes + 3) / 4;
int len = nbytes / nnops;
int remains = nbytes - nnops * len;
for (i = 0; i < remains; i++) {
emit_block(prefixes, len);
emit_8(0x90); // NOP
}
for (; i < nnops; i++) {
emit_block(prefixes, len - 1);
emit_8(0x90); // NOP
}
#else
int nloops = nbytes / 16;
while (nloops-- > 0)
emit_block(f32_16, sizeof(f32_16));
nbytes %= 16;
if (nbytes)
emit_block(f32_patt[nbytes - 1], nbytes);
#endif
#else
#warning "FIXME: tune for your target"
for (int i = 0; i < nbytes; i++)
emit_8(0);
#endif
return code_ptr();
}

8
SheepShaver/src/kpx_cpu/src/cpu/jit/basic-dyngen.hpp
View File

@ -290,14 +290,6 @@ basic_dyngen::direct_call_possible(uintptr target) const
return false;
}
inline uint8 *
basic_dyngen::gen_align(int align)
{
while ((uintptr)code_ptr() & (align - 1))
inc_code_ptr(1);
return code_ptr();
}
inline uint8 *
basic_dyngen::gen_start()
{