Skip to content

Preserve OSIZE for APX EVEX MAP4 #378

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
RatinCN wants to merge 1 commit into
base: main
Choose a base branch
from
Open

Preserve OSIZE for APX EVEX MAP4 #378

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
12 changes: 7 additions & 5 deletions src/disasm.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -301,6 +301,7 @@ class CDetourDis
BOOL m_bRaxOverride; // AMD64 only
BOOL m_bVex;
BOOL m_bEvex;
BOOL m_bEvexMap4;
BOOL m_bF2;
BOOL m_bF3; // x86 only
BYTE m_nSegmentOverride;
Expand Down Expand Up @@ -334,7 +335,8 @@ CDetourDis::CDetourDis(_Out_opt_ PBYTE *ppbTarget, _Out_opt_ LONG *plExtra) :
m_bF2(FALSE),
m_bF3(FALSE),
m_bVex(FALSE),
m_bEvex(FALSE)
m_bEvex(FALSE),
m_bEvexMap4(FALSE)
{
m_ppbTarget = ppbTarget ? ppbTarget : &m_pbScratchTarget;
m_plExtra = plExtra ? plExtra : &m_lScratchExtra;
Expand Down Expand Up @@ -380,10 +382,9 @@ PBYTE CDetourDis::CopyBytes(REFCOPYENTRY pEntry, PBYTE pbDst, PBYTE pbSrc)
nBytesFixed = nFixedSize + ((nFlagBits & RAX) ? 4 : 0);
}
#endif
else if (m_bVex || m_bEvex) {
// VEX/EVEX pp field does not shrink immediates to 16-bit.
// This matters for EVEX MAP4 (APX) where entries like opcode 81
// (Group 1 imm32) have nFixedSize=6 but nFixedSize16=4.
else if ((m_bVex || m_bEvex) && !m_bEvexMap4) {
// For non-MAP4 VEX/EVEX instructions, pp is a mandatory prefix and
// does not shrink immediates to 16-bit.
nBytesFixed = nFixedSize;
}
else {
Expand Down Expand Up @@ -799,6 +800,7 @@ PBYTE CDetourDis::CopyVexEvexCommon(BYTE m, PBYTE pbDst, PBYTE pbSrc, BYTE p, BY
case 2: return CopyBytes(&ceF38, pbDst, pbSrc);
case 3: return CopyBytes(&ceF3A, pbDst, pbSrc);
case 4: // MAP4 (APX) - promoted legacy MAP0 instructions.
m_bEvexMap4 = m_bEvex;
pEntry = &s_rceCopyTable[pbSrc[0]];
return (this->*pEntry->pfCopy)(pEntry, pbDst, pbSrc);
}
Expand Down