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Store 32-bit and 64-bit data in a single table

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This commit is contained in:
Alexis Engelke
2019-02-23 16:32:39 +01:00
parent 256806e4b6
commit 67ae0f8de8
3 changed files with 43 additions and 39 deletions
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38
decode.c
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@@ -12,21 +12,16 @@
#define LIKELY(x) __builtin_expect((x), 1)
#define UNLIKELY(x) __builtin_expect((x), 0)
#if defined(ARCH_386)
#define FD_DECODE_TABLE_DATA_32
static const uint8_t _decode_table32[] = {
#define FD_DECODE_TABLE_DATA
static const uint8_t _decode_table[] = {
#include <decode-table.inc>
};
#undef FD_DECODE_TABLE_DATA_32
#endif
#undef FD_DECODE_TABLE_DATA
#if defined(ARCH_X86_64)
#define FD_DECODE_TABLE_DATA_64
static const uint8_t _decode_table64[] = {
// Defines FD_TABLE_OFFSET_32 and FD_TABLE_OFFSET_64, if available
#define FD_DECODE_TABLE_DEFINES
#include <decode-table.inc>
};
#undef FD_DECODE_TABLE_DATA_64
#endif
#undef FD_DECODE_TABLE_DEFINES
enum DecodeMode {
DECODE_64 = 0,
@@ -369,7 +364,7 @@ int
fd_decode(const uint8_t* buffer, size_t len_sz, int mode_int, uintptr_t address,
FdInstr* instr)
{
const uint8_t* decode_table = NULL;
const uint16_t* table = NULL;
int len = len_sz > 15 ? 15 : len_sz;
DecodeMode mode = mode_int == 32 ? DECODE_32 :
@@ -378,14 +373,14 @@ fd_decode(const uint8_t* buffer, size_t len_sz, int mode_int, uintptr_t address,
// Ensure that we can actually handle the decode request
#if defined(ARCH_386)
if (mode == DECODE_32)
decode_table = _decode_table32;
table = (uint16_t*) &_decode_table[FD_TABLE_OFFSET_32];
#endif
#if defined(ARCH_X86_64)
if (mode == DECODE_64)
decode_table = _decode_table64;
table = (uint16_t*) &_decode_table[FD_TABLE_OFFSET_64];
#endif
if (UNLIKELY(decode_table == NULL))
if (UNLIKELY(table == NULL))
return -2;
int retval;
@@ -402,26 +397,25 @@ fd_decode(const uint8_t* buffer, size_t len_sz, int mode_int, uintptr_t address,
}
off += retval;
const uint16_t* table = (uint16_t*) decode_table;
uint32_t kind = ENTRY_TABLE256;
if (UNLIKELY(prefixes & PREFIX_ESC_MASK))
{
uint32_t escape = prefixes & PREFIX_ESC_MASK;
table = (uint16_t*) &decode_table[table[0x0F] & ~7];
table = (uint16_t*) &_decode_table[table[0x0F] & ~7];
if (escape == PREFIX_ESC_0F38)
{
table = (uint16_t*) &decode_table[table[0x38] & ~7];
table = (uint16_t*) &_decode_table[table[0x38] & ~7];
}
else if (escape == PREFIX_ESC_0F3A)
{
table = (uint16_t*) &decode_table[table[0x3A] & ~7];
table = (uint16_t*) &_decode_table[table[0x3A] & ~7];
}
}
// First walk through full-byte opcodes. We do at most three iterations.
while (kind == ENTRY_TABLE256 && LIKELY(off < len))
ENTRY_UNPACK(table, kind, decode_table, table[buffer[off++]]);
ENTRY_UNPACK(table, kind, _decode_table, table[buffer[off++]]);
// Then, walk through ModR/M-encoded opcode extensions.
if ((kind == ENTRY_TABLE8 || kind == ENTRY_TABLE72) && LIKELY(off < len))
@@ -438,7 +432,7 @@ fd_decode(const uint8_t* buffer, size_t len_sz, int mode_int, uintptr_t address,
else
entry = table[(buffer[off] >> 3) & 7];
ENTRY_UNPACK(table, kind, decode_table, entry);
ENTRY_UNPACK(table, kind, _decode_table, entry);
}
// Finally, handle mandatory prefixes (which behave like an opcode ext.).
@@ -452,7 +446,7 @@ fd_decode(const uint8_t* buffer, size_t len_sz, int mode_int, uintptr_t address,
// for the 0x66 prefix, which could otherwise override the operand
// size of general purpose registers.
prefixes &= ~(PREFIX_OPSZ | PREFIX_REPNZ | PREFIX_REP);
ENTRY_UNPACK(table, kind, decode_table, table[index]);
ENTRY_UNPACK(table, kind, _decode_table, table[index]);
}
if (UNLIKELY(kind != ENTRY_INSTR))