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zydis
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Many encoder bug-fixes, movabs support

This commit is contained in:
Joel Höner 2017-01-23 21:52:26 +01:00
parent 616cd00ec8
commit fda4f15c6d
1 changed files with 47 additions and 44 deletions
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91
src/Encoder.c
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@ -82,6 +82,7 @@ typedef struct ZydisEncoderTableEntry_
ZydisPrefixBit prefixBits;
uint8_t mandatoryPrefix; // 0x00 = None
uint8_t modrmReg; // 0xFF = None
const char* cmt;
} ZydisEncoderTableEntry;
struct ZydisPrefixAcceptMapping
@ -553,20 +554,38 @@ static ZydisBool ZydisIsStackReg(ZydisRegister reg)
return ZydisIsSPReg(reg) || ZydisIsBPReg(reg);
}
static ZydisStatus ZydisSetREXWIfRequired(ZydisEncoderContext* ctx, ZydisRegister reg)
static ZydisStatus ZydisPrepareSegmentPrefix(ZydisEncoderContext* ctx,
ZydisRegister segment, ZydisRegister base)
{
ZydisRegisterClass regClass = ZydisRegisterGetClass(reg);
if (regClass == ZYDIS_REGCLASS_GPR64)
// Segment prefix required?
switch (segment)
{
if (ctx->info->mode == ZYDIS_DISASSEMBLER_MODE_64BIT)
case ZYDIS_REGISTER_ES:
ctx->info->attributes |= ZYDIS_ATTRIB_HAS_SEGMENT_ES;
break;
case ZYDIS_REGISTER_SS:
if (!ZydisIsStackReg(base))
{
ctx->info->details.rex.W = 0x01;
ctx->info->attributes |= ZYDIS_ATTRIB_HAS_REX;
ctx->info->attributes |= ZYDIS_ATTRIB_HAS_SEGMENT_SS;
}
else
break;
case ZYDIS_REGISTER_CS:
ctx->info->attributes |= ZYDIS_ATTRIB_HAS_SEGMENT_CS;
break;
case ZYDIS_REGISTER_DS:
if (ZydisIsStackReg(base))
{
return ZYDIS_STATUS_IMPOSSIBLE_INSTRUCTION; // TODO
ctx->info->attributes |= ZYDIS_ATTRIB_HAS_SEGMENT_DS;
}
break;
case ZYDIS_REGISTER_FS:
ctx->info->attributes |= ZYDIS_ATTRIB_HAS_SEGMENT_FS;
break;
case ZYDIS_REGISTER_GS:
ctx->info->attributes |= ZYDIS_ATTRIB_HAS_SEGMENT_GS;
break;
default:
return ZYDIS_STATUS_IMPOSSIBLE_INSTRUCTION; // TODO: Better status.
}
return ZYDIS_STATUS_SUCCESS;
@ -579,6 +598,8 @@ static ZydisStatus ZydisPrepareMemoryOperand(ZydisEncoderContext* ctx,
ZYDIS_ASSERT(operand);
ZYDIS_ASSERT(tableEntry);
ZYDIS_CHECK(ZydisPrepareSegmentPrefix(ctx, operand->mem.segment, operand->mem.base));
// Absolute memory access? Special case.
if (operand->mem.base == ZYDIS_REGISTER_NONE)
{
@ -678,37 +699,6 @@ static ZydisStatus ZydisPrepareMemoryOperand(ZydisEncoderContext* ctx,
return ZYDIS_STATUS_INVALID_PARAMETER; // TODO
}
// Segment prefix required?
switch (operand->mem.segment)
{
case ZYDIS_REGISTER_ES:
ctx->info->attributes |= ZYDIS_ATTRIB_HAS_SEGMENT_ES;
break;
case ZYDIS_REGISTER_SS:
if (!ZydisIsStackReg(operand->mem.base))
{
ctx->info->attributes |= ZYDIS_ATTRIB_HAS_SEGMENT_SS;
}
break;
case ZYDIS_REGISTER_CS:
ctx->info->attributes |= ZYDIS_ATTRIB_HAS_SEGMENT_CS;
break;
case ZYDIS_REGISTER_DS:
if (ZydisIsStackReg(operand->mem.base))
{
ctx->info->attributes |= ZYDIS_ATTRIB_HAS_SEGMENT_DS;
}
break;
case ZYDIS_REGISTER_FS:
ctx->info->attributes |= ZYDIS_ATTRIB_HAS_SEGMENT_FS;
break;
case ZYDIS_REGISTER_GS:
ctx->info->attributes |= ZYDIS_ATTRIB_HAS_SEGMENT_GS;
break;
default:
return ZYDIS_STATUS_IMPOSSIBLE_INSTRUCTION; // TODO: Better status.
}
// SIB byte required? rSP can only be encoded with SIB.
if (operand->mem.index || operand->mem.scale || ZydisIsSPReg(operand->mem.base))
{
@ -809,12 +799,27 @@ static ZydisStatus ZydisPrepareOperand(ZydisEncoderContext* ctx,
switch (tableEntry->encoding)
{
case ZYDIS_OPERAND_ENCODING_NONE:
break; // Nothing to do.
// For some encodings, we have to switch on the sem op type.
switch (tableEntry->type)
{
case ZYDIS_SEM_OPERAND_TYPE_MOFFS16:
case ZYDIS_SEM_OPERAND_TYPE_MOFFS32:
case ZYDIS_SEM_OPERAND_TYPE_MOFFS64:
ZYDIS_CHECK(ZydisPrepareSegmentPrefix(
ctx, operand->mem.segment, ZYDIS_REGISTER_NONE
));
ctx->imms[0] = operand->mem.disp.value.sqword;
ctx->immBitSizes[0] = operand->mem.disp.dataSize;
break;
default:
// Hidden operand, nothing to encode.
break;
}
break;
case ZYDIS_OPERAND_ENCODING_REG:
{
ZYDIS_ASSERT(!ctx->info->details.modrm.reg);
ZYDIS_CHECK(ZydisPrepareRegOperand(ctx, operand->reg, 'R'));
ZYDIS_CHECK(ZydisSetREXWIfRequired(ctx, operand->reg));
} break;
case ZYDIS_OPERAND_ENCODING_RM:
case ZYDIS_OPERAND_ENCODING_RM_CD2:
@ -839,7 +844,6 @@ static ZydisStatus ZydisPrepareOperand(ZydisEncoderContext* ctx,
else if (operand->type == ZYDIS_OPERAND_TYPE_REGISTER)
{
ZYDIS_CHECK(ZydisPrepareRegOperand(ctx, operand->reg, 'B'));
ZYDIS_CHECK(ZydisSetREXWIfRequired(ctx, operand->reg));
ctx->info->details.modrm.mod = 0x03 /* reg */;
}
@ -853,7 +857,6 @@ static ZydisStatus ZydisPrepareOperand(ZydisEncoderContext* ctx,
ctx->info->opcode += reg & 0x07;
ctx->info->details.rex.B = (reg & 0x08) >> 3;
if (ctx->info->details.rex.B) ctx->info->attributes |= ZYDIS_ATTRIB_HAS_REX;
//ZYDIS_CHECK(ZydisSetREXWIfRequired(ctx, operand->reg));
break;
}
case ZYDIS_OPERAND_ENCODING_VVVV:
@ -1057,7 +1060,7 @@ ZydisStatus ZydisEncoderEncodeInstruction(void* buffer, size_t* bufferLen,
info->details.evex.B = (pb & ZYDIS_PREFBIT_EVEX_B ) ? 1 : 0;
info->details.evex.L2 = (pb & ZYDIS_PREFBIT_EVEX_L2) ? 1 : 0;
info->details.vex.L = (pb & ZYDIS_PREFBIT_VEX_L ) ? 1 : 0;
if (info->details.rex.W)
if (pb & ZYDIS_PREFBIT_REX_W)
{
info->details.rex.W = 1;
info->attributes |= ZYDIS_ATTRIB_HAS_REX;