x64dbg
/
zydis
mirror of https://github.com/x64dbg/zydis
1
0
Fork 0
Code Releases Activity

Fixed priority of mandatory-prefixes

This commit is contained in:
flobernd 2017-06-17 21:01:57 +02:00
parent 58b15163f2
commit f20dc484cd
1 changed files with 10 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
src/Decoder.c
View File

@ -61,8 +61,9 @@ typedef struct ZydisDecoderContext_
/**
* @brief Contains the prefix that should be traited as the mandatory-prefix, if the current
* instruction needs one.
* 0x66 has precedence over 0xF3/0xF2 and the last 0xF3/0xF2 has precedence over
* previous ones.
*
* The last 0xF3/0xF2 prefix has precedence over previous ones and 0xF3/0xF2 in
* general has precedence over 0x66.
*/
uint8_t mandatoryCandidate;
/**
@ -462,6 +463,7 @@ static ZydisStatus ZydisDecodeMVEX(ZydisDecoderContext* context, ZydisInstructio
context->cache.B = 0x01 & ~info->details.mvex.B;
context->cache.R2 = 0x01 & ~info->details.mvex.R2;
context->cache.V2 = 0x01 & ~info->details.mvex.V2;
context->cache.LL = 2;
context->cache.v_vvvv =
((0x01 & ~info->details.mvex.V2) << 4) | (0x0F & ~info->details.mvex.vvvv);
@ -706,17 +708,11 @@ static ZydisStatus ZydisCollectOptionalPrefixes(ZydisDecoderContext* context,
++info->details.prefixes.hasF0;
break;
case 0xF2:
if (context->mandatoryCandidate != 0x66)
{
context->mandatoryCandidate = 0xF2;
}
context->mandatoryCandidate = 0xF2;
++info->details.prefixes.hasF2;
break;
case 0xF3:
if (context->mandatoryCandidate != 0x66)
{
context->mandatoryCandidate = 0xF3;
}
context->mandatoryCandidate = 0xF3;
++info->details.prefixes.hasF3;
break;
case 0x2E:
@ -744,7 +740,10 @@ static ZydisStatus ZydisCollectOptionalPrefixes(ZydisDecoderContext* context,
context->lastSegmentPrefix = 0x65;
break;
case 0x66:
context->mandatoryCandidate = 0x66;
if (!context->mandatoryCandidate)
{
context->mandatoryCandidate = 0x66;
}
++info->details.prefixes.has66;
info->attributes |= ZYDIS_ATTRIB_HAS_OPERANDSIZE;
break;
@ -2401,10 +2400,6 @@ static void ZydisSetAVXInformation(ZydisDecoderContext* context,
/* ---------------------------------------------------------------------------------------------- */
// TODO: Update attributes after a valid instruction was found
/* ---------------------------------------------------------------------------------------------- */
static ZydisStatus ZydisNodeHandlerXOP(ZydisInstructionInfo* info, uint16_t* index)
{
ZYDIS_ASSERT(info);
@ -2625,7 +2620,6 @@ static ZydisStatus ZydisNodeHandlerOpcode(ZydisDecoderContext* context,
}
break;
case ZYDIS_INSTRUCTION_ENCODING_3DNOW:
// TODO: We need to change this
// All 3DNOW (0x0F 0x0F) instructions are using the same operand encoding. We just
// decode a random (pi2fw) instruction and extract the actual opcode later.
*index = 0x0C;