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zydis
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Implemented address size prefix encoding, bugfixes

This commit is contained in:
Joel Höner 2017-01-22 15:46:20 +01:00
parent b3c8d44bda
commit 587187af89
1 changed files with 54 additions and 5 deletions
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59
src/Encoder.c
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@ -508,7 +508,7 @@ static ZydisStatus ZydisPrepareMemoryOperand(ZydisEncoderContext* ctx,
ctx->info->details.modrm.mod = 0x00; ctx->info->details.modrm.mod = 0x00;
ctx->info->details.modrm.rm = 0x05 /* memory */; ctx->info->details.modrm.rm = 0x05 /* memory */;
} }
// In AMD64 mode, we have to build a SIB. // In AMD64 mode, we have to build a special SIB.
else else
{ {
ctx->info->details.modrm.mod = 0x00; ctx->info->details.modrm.mod = 0x00;
@ -525,6 +525,48 @@ static ZydisStatus ZydisPrepareMemoryOperand(ZydisEncoderContext* ctx,
// Process base register. // Process base register.
ZYDIS_CHECK(ZydisPrepareRegOperand(ctx, operand->mem.base, 'B')); ZYDIS_CHECK(ZydisPrepareRegOperand(ctx, operand->mem.base, 'B'));
// Address size prefix required?
ZydisRegisterClass baseRegClass = ZydisRegisterGetClass(operand->mem.base);
switch (baseRegClass)
{
case ZYDIS_REGCLASS_GPR16:
switch (ctx->info->mode)
{
case ZYDIS_DISASSEMBLER_MODE_16BIT:
break; // Nothing to do.
case ZYDIS_DISASSEMBLER_MODE_32BIT:
ctx->info->attributes |= ZYDIS_ATTRIB_HAS_ADDRESSSIZE;
break;
case ZYDIS_DISASSEMBLER_MODE_64BIT:
// AMD64 doesn't allow for 16 bit addressing.
return ZYDIS_STATUS_IMPOSSIBLE_INSTRUCTION; // TODO
default:
return ZYDIS_STATUS_INVALID_PARAMETER; // TODO
}
break;
case ZYDIS_REGCLASS_GPR32:
switch (ctx->info->mode)
{
case ZYDIS_DISASSEMBLER_MODE_16BIT:
return ZYDIS_STATUS_IMPOSSIBLE_INSTRUCTION; // TODO
case ZYDIS_DISASSEMBLER_MODE_32BIT:
break; // Nothing to do.
case ZYDIS_DISASSEMBLER_MODE_64BIT:
ctx->info->attributes |= ZYDIS_ATTRIB_HAS_ADDRESSSIZE;
default:
return ZYDIS_STATUS_INVALID_PARAMETER; // TODO
}
break;
case ZYDIS_REGCLASS_GPR64:
if (ctx->info->mode != ZYDIS_DISASSEMBLER_MODE_64BIT)
{
return ZYDIS_STATUS_IMPOSSIBLE_INSTRUCTION; // TODO
}
break;
default:
return ZYDIS_STATUS_INVALID_PARAMETER; // TODO
}
// Segment prefix required? // Segment prefix required?
switch (operand->mem.segment) switch (operand->mem.segment)
{ {
@ -559,12 +601,19 @@ static ZydisStatus ZydisPrepareMemoryOperand(ZydisEncoderContext* ctx,
// SIB byte required? // SIB byte required?
if (operand->mem.index || operand->mem.scale) if (operand->mem.index || operand->mem.scale)
{ {
// Base and index register must be of same register class, verify.
if (ZydisRegisterGetClass(operand->mem.index) != baseRegClass)
{
return ZYDIS_STATUS_IMPOSSIBLE_INSTRUCTION; // TODO
}
// Translate scale to SIB format.
switch (operand->mem.scale) switch (operand->mem.scale)
{ {
case 1: ctx->info->details.sib.index = 0x00; break; case 1: ctx->info->details.sib.scale = 0x00; break;
case 2: ctx->info->details.sib.index = 0x01; break; case 2: ctx->info->details.sib.scale = 0x01; break;
case 4: ctx->info->details.sib.index = 0x02; break; case 4: ctx->info->details.sib.scale = 0x02; break;
case 8: ctx->info->details.sib.index = 0x03; break; case 8: ctx->info->details.sib.scale = 0x03; break;
default: return ZYDIS_STATUS_IMPOSSIBLE_INSTRUCTION; // TODO default: return ZYDIS_STATUS_IMPOSSIBLE_INSTRUCTION; // TODO
} }