955 lines
37 KiB
C++
955 lines
37 KiB
C++
/**************************** omf2asm.cpp *********************************
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* Author: Agner Fog, modified by Don Clugston
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* Date created: 2007-05-27
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* Last modified: 2014-05-32
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* Project: objconv
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* Module: omf2asm.cpp
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* Description:
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* Module for disassembling OMF object files
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*
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* (c) 2007-2014 GNU General Public License www.gnu.org/copyleft/gpl.html
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*****************************************************************************/
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#include "stdafx.h"
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// Constructor
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COMF2ASM::COMF2ASM() {
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}
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// Convert
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void COMF2ASM::Convert() {
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// Do the conversion
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// Tell disassembler
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Disasm.Init(0, 0);
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// Make temporary Segments table
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CountSegments();
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// Make external symbols in Disasm
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MakeExternalSymbolsTable();
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// Make public symbols in Disasm
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MakePublicSymbolsTable();
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// Make symbol table entries for communal symbols.
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MakeCommunalSymbolsTable();
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// Make Segment list and relocations list
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MakeSegmentList();
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// Make group definitions
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MakeGroupDefinitions();
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// Disassemble
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Disasm.Go();
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// Take over output file from Disasm
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*this << Disasm.OutFile;
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}
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void COMF2ASM::CountSegments() {
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// Make temporary Segments table
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uint32 i; // Record number
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uint32 NameIndex; // Name index
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uint32 ClassIndex; // Class name index
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SOMFSegment SegRecord; // Segment record
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// Define structure of attributes
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OMF_SAttrib Attributes;
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// Initialize temporary list of segments. Entry 0 is blank
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Segments.PushZero();
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// Search for SEGDEF records
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for (i = 0; i < NumRecords; i++) {
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if (Records[i].Type2 == OMF_SEGDEF) {
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// SEGDEF record
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Records[i].Index = 3;
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// Loop through entries in record. There should be only 1
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while (Records[i].Index < Records[i].End) {
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// Read segment attributes
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Attributes.b = Records[i].GetByte();
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if (Attributes.u.A == 0) {
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// Frame and Offset only included if A = 0
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Records[i].GetWord(); // Frame ignored
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SegRecord.Offset = Records[i].GetByte();
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}
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else SegRecord.Offset = 0;
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SegRecord.Size = Records[i].GetNumeric();
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NameIndex = Records[i].GetIndex();
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ClassIndex = Records[i].GetIndex(); // Class index
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Records[i].GetIndex(); // Overlay index ignored
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SegRecord.NameO = GetLocalNameO(NameIndex); // Segment name
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if (Attributes.u.B) {
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// Segment is big
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if (Attributes.u.P) {
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// 32 bit segment. Big means 2^32 bytes!
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err.submit(2306);
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}
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else {
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// 16 bit segment. Big means 2^16 bytes
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SegRecord.Size = 0x10000;
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}
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}
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// Get word size
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SegRecord.WordSize = Attributes.u.P ? 32 : 16;
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// Get alignment
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switch (Attributes.u.A) {
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case 0: // Absolute segment
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case 1: // Byte alignment
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SegRecord.Align = 0;
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break;
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case 2: // Word alignment
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SegRecord.Align = 1;
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break;
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case 3: // Paragraph alignment
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SegRecord.Align = 4;
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break;
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case 4: // Page alignment
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SegRecord.Align = 16;
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break;
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case 5: // DWord alignment
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SegRecord.Align = 2;
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break;
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default: // Unknown
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SegRecord.Align = 3; // Arbitrary value
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break;
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}
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// Get further attributes from class name
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char * ClassName = GetLocalName(ClassIndex);
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// Convert class name to upper case
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uint32 n = (uint32)strlen(ClassName);
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for (uint32 j = 0; j < n; j++) ClassName[j] &= ~0x20;
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// Search for known class names.
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// Standard names are CODE, DATA, BSS, CONST, STACK
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if (strstr(ClassName, "CODE") || strstr(ClassName, "TEXT")) {
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// Code segment
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SegRecord.Type = 1;
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}
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else if (strstr(ClassName, "DATA")) {
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// Data segment
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SegRecord.Type = 2;
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}
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else if (strstr(ClassName, "BSS")) {
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// Unitialized data segment
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SegRecord.Type = 3;
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}
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else if (strstr(ClassName, "CONST")) {
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// Constant data segment
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SegRecord.Type = 4;
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}
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else if (strstr(ClassName, "STACK")) {
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// Stack segment.
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SegRecord.Type = 0;
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}
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else {
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// Unknown/user defined class. Assume data segment
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SegRecord.Type = 2;
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}
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// Store temporary segment record
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Segments.Push(SegRecord);
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}
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if (Records[i].Index != Records[i].End) err.submit(1203); // Check for consistency
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}
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}
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FirstComDatSection = Segments.GetNumEntries();
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// Communal sections (as used by Digital Mars):
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// This part by Don Clugston
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for (i = 0; i < NumRecords; i++) {
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if (Records[i].Type2 == OMF_COMDAT) {
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Records[i].Index = 3;
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uint8 flags = Records[i].GetByte();
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if ((flags & 2) != 0) {
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// don't support iterated data yet
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err.submit(2318); // Error message: not supported
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continue;
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}
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uint8 attribs = Records[i].GetByte();
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uint8 align = Records[i].GetByte();
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uint32 ofs = Records[i].GetNumeric();
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Records[i].GetIndex(); // type (ignore)
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//uint16 publicBase = 0;
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uint16 publicSegment = 0;
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// From the OMF Spec 1.1: "If alloc type is EXPLICIT, public base is present and is
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// identical to public base fields BaseGroup, Base Segment & BaseFrame in the PUBDEF."
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// BUT: In the diagram in the spec it is described as 1-2 bytes (ie, an Index field).
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// but in PUBDEF, those fields are Index, Index, or Index, zero, Index. (2-5 bytes)
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// The diagram appears to be erroneous.
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if ((attribs & 0xF) == 0){
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//publicBase = Records[i].GetIndex();
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publicSegment = Records[i].GetIndex();
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if (publicSegment == 0) {
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//Records[i].GetIndex(); // skip frame in this case
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// I don't have the Digital Mars obj spec, but this seems to help ??
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publicSegment = Records[i].GetIndex(); // ??
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}
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}
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uint16 publicName = Records[i].GetIndex();
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uint32 RecSize = Records[i].End - Records[i].Index; // Calculate size of data
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if (attribs & 0xF) {
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SegRecord.Type = 0x1000 | (attribs & 0xFF);
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SegRecord.WordSize = (attribs & 0x2) ? 32 : 16;
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}
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else {
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// use value from segdef
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SegRecord.Type = 0x1000 | Segments[publicSegment].Type;
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SegRecord.WordSize = Segments[publicSegment].WordSize;
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}
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//SegRecord.Type |= 1;//!!
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if (align != 0) {
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// alignment: (none), byte, word, paragraph, page, dword, arbitrary, arbitrary.
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static const int alignvalues[] = {0, 0, 1, 4, 16, 2, 3, 3};
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SegRecord.Align = alignvalues[align & 0x7];
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}
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else { // use value from segdef
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SegRecord.Align = Segments[publicSegment].Align;
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}
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SegRecord.Size = RecSize;
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// Get function name
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const char * name = GetLocalName(publicName);
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// Make a section name by putting _text$ before function name
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uint32 ComdatSectionNameIndex = NameBuffer.Push("_text$", 6);
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NameBuffer.PushString(name); // append function name
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SegRecord.NameO = ComdatSectionNameIndex;
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SegRecord.NameIndex = publicName;
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if (flags & 1) {
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// continuation.
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// Add to the length to the previous entry.
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Segments[Segments.GetNumEntries()-1].Size += RecSize;
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}
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else {
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SegRecord.Offset = ofs;
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Segments.Push(SegRecord);
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}
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}
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}
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// Communal sections (as used by Borland):
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for (i = 0; i < NumRecords; i++) {
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if (Records[i].Type2 == OMF_COMDEF) {
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uint32 DType, DSize = 0, DNum;
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uint16 Segment = 0;
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const char * FuncName = 0;
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// Loop through possibly multiple entries in record
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while (Records[i].Index < Records[i].End) {
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// Get function name
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FuncName = Records[i].GetString();
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Records[i].GetByte(); // Type index, should be 0, ignored
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DType = Records[i].GetByte(); // Data type
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switch (DType) {
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case 0x61:
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DNum = Records[i].GetLength();
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DSize = Records[i].GetLength() * DNum;
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break;
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case 0x62:
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DSize = Records[i].GetLength();
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break;
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default:
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DSize = Records[i].GetLength();
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if (DType < 0x60) { // Borland segment index
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Segment = DType;
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break;
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}
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err.submit(2016); // unknown type
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break;
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}
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}
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if (Segment >= Segments.GetNumEntries()) {err.submit(2016); return;}
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// Copy segment record
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SegRecord = Segments[Segment];
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// Make a section name as SEGMENTNAME$FUNCTIONNAME
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const char * SegmentName = NameBuffer.Buf() + SegRecord.NameO;
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uint32 ComdatSectionNameIndex = NameBuffer.Push(SegmentName, strlen(SegmentName));
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NameBuffer.Push("$", 1);
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NameBuffer.PushString(FuncName); // append function name
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SegRecord.NameO = ComdatSectionNameIndex;
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SegRecord.Size = DSize;
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SegRecord.Type |= 0x1000;
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//SegRecord.BufOffset = ??
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// Store segment
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Segments.Push(SegRecord);
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if (Records[i].Index != Records[i].End) err.submit(1203); // Check for consistency
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}
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}
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// Number of segments, not including blank zero entry
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NumSegments = Segments.GetNumEntries() - 1;
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}
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void COMF2ASM::MakeExternalSymbolsTable() {
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// Make symbol table and string table entries for external symbols
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uint32 iextsym; // External symbol index
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uint32 isymo; // Symbol index in disassembler
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uint32 NumExtSym = SymbolNameOffset.GetNumEntries(); // Number of external symbols
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ExtdefTranslation.SetNum(NumExtSym+1); // Allocate space in symbol index translation table
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// Loop through external symbol names
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for (iextsym = 1; iextsym < NumExtSym; iextsym++) {
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// Get name
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const char * Name = GetSymbolName(iextsym);
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// Define symbol
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isymo = Disasm.AddSymbol(0, 0, 0, 0, 0x20, 0, Name);
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// Update table for translating old EXTDEF number to disassembler symbol index
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ExtdefTranslation[iextsym] = isymo;
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}
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}
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void COMF2ASM::MakePublicSymbolsTable() {
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// Make symbol table entries for public symbols
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uint32 i; // Record index
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char * string; // Symbol name
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uint32 Segment; // Segment
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uint32 Offset; // Offset
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uint32 isymo; // Symbol number in disasm
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uint32 CommunalSection = FirstComDatSection; // Index to communal section
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PubdefTranslation.Push(0); // Make index 0 = 0
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// Search for PUBDEF records
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for (i = 0; i < NumRecords; i++) {
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if (Records[i].Type2 == OMF_PUBDEF) {
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// PUBDEF record
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Records[i].Index = 3;
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Records[i].GetIndex(); // Group. Ignore
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Segment = Records[i].GetIndex(); // Segment
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if (Segment == 0) Records[i].GetWord(); // Base frame. Ignore
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// Loop through strings in record
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while (Records[i].Index < Records[i].End) {
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string = Records[i].GetString(); // Symbol name
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Offset = Records[i].GetNumeric(); // Offset to segment
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Records[i].GetIndex(); // Type index. Ignore
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// Define symbol
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isymo = Disasm.AddSymbol(Segment, Offset, 0, 0, 4, 0, string);
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// Update table for translating old PUBDEF number to disassembler symbol index
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PubdefTranslation.Push(isymo);
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}
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if (Records[i].Index != Records[i].End) err.submit(1203); // Check for consistency
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}
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}
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// Search for OMF_COMDEF records
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for (i = 0; i < NumRecords; i++) {
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if (Records[i].Type2 == OMF_COMDEF) {
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// COMDEF record, Borland communal name
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uint32 DType;
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//uint32 DSize;
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//uint32 DNum;
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Records[i].Index = 3;
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// Loop through possibly multiple entries in record
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while (Records[i].Index < Records[i].End) {
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string = Records[i].GetString();
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Records[i].GetByte(); // Type index, should be 0, ignore
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DType = Records[i].GetByte(); // Data type
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switch (DType) {
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case 0x61:
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//DNum = Records[i].GetLength();
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//DSize = Records[i].GetLength();
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continue; // Don't know what to do with this type. Ignore
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case 0x62:
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//DSize = Records[i].GetLength();
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continue; // Don't know what to do with this type. Ignore
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default:
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//DSize = Records[i].GetLength();
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if (DType < 0x60) { // Borland segment index
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break;
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}
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continue; // Unknown type. Ignore
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}
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// Define symbol
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Segment = CommunalSection;
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isymo = Disasm.AddSymbol(Segment, 0, 0, 0, 0x10, 0, string);
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// Update table for translating old PUBDEF number to disassembler symbol index
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PubdefTranslation.Push(isymo);
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}
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CommunalSection++;
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if (Records[i].Index != Records[i].End) err.submit(1203); // Check for consistency
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}
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}
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}
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void COMF2ASM::MakeCommunalSymbolsTable() {
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// Make symbol table entries for communal symbols
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char * string; // Symbol name
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// Search for communal records
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for (uint32 i = 0; i < NumRecords; i++) {
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// Count communal records
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if (Records[i].Type2 == OMF_CEXTDEF) {
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Records[i].Index = 3;
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// Loop through strings in record
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while (Records[i].Index < Records[i].End) {
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uint32 LIndex = Records[i].GetIndex();
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Records[i].GetIndex(); // Group. Ignore
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string = GetLocalName(LIndex);
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// find section with same name
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int32 section = 0;
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for (uint32 j = 0; j < Segments.GetNumEntries(); j++) {
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if (Segments[j].NameIndex == LIndex) {
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section = (int32)j; break;
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}
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}
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// Define symbol
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Disasm.AddSymbol(section, 0, 0, 0, 0x10, 0, string);
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}
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}
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}
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}
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void COMF2ASM::MakeGroupDefinitions() {
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// Make segment group definitions
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uint32 i; // Record index
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// Search for group records
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for (i = 0; i < NumRecords; i++) {
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if (Records[i].Type2 == OMF_GRPDEF) {
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// GRPDEF record
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Records[i].Index = 3;
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// Get group name
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uint32 ClassIndex = Records[i].GetIndex();
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char * GroupName = GetLocalName(ClassIndex);
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// Define group
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Disasm.AddSectionGroup(GroupName, 0);
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// Loop through remaining entries in record
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while (Records[i].Index < Records[i].End) {
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// Entry type should be 0xFF
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uint8 Type = Records[i].GetByte();
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// Get member name
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int32 NameIndex = Records[i].GetIndex();
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// Check if type valid
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if (Type == 0xFF && NameIndex > 0) {
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// A group member is found. Add member to group
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Disasm.AddSectionGroup(GroupName, NameIndex);
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}
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}
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if (Records[i].Index != Records[i].End) err.submit(1203); // Check for consistency
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}
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}
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}
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// MakeSegmentList
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void COMF2ASM::MakeSegmentList() {
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// Make Sections list in Disasm
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int32 SegNum; // Segment number
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int32 Segment = 0; // Segment number in OMF record
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uint32 RecNum; // OMF record number
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uint32 LastDataRecord; // OMF record number of last LEDATA record
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uint32 RecOffset; // Segment offset of LEDATA, LIDATA record
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uint32 RecSize; // Data size of LEDATA, LIDATA record
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uint32 LastDataRecordSize; // Last RecSize
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uint32 LastOffset; // Last RecOffset
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int8 * LastDataRecordPointer; // Point to last raw data
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uint32 BufOffset; // Offset of segment into SegmentData buffer
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CMemoryBuffer TempBuf; // Temporary buffer for building raw data
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// Loop through segments
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for (SegNum = 1; SegNum <= NumSegments; SegNum++) {
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// Get size
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uint32 SegmentSize = Segments[SegNum].Size;
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if (SegmentSize == 0) continue; // Empty segment
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// Allocate temporary data buffer and reset it
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TempBuf.SetSize(SegmentSize + 16);
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int FillByte = 0; // Byte to fill memory with
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if (Segments[SegNum].Type == 1) {
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// Code segment. Fill any unused bytes with NOP opcode = 0x90
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FillByte = 0x90;
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}
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memset(TempBuf.Buf(), FillByte, SegmentSize + 16);// Reset to all 0 or NOP
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LastDataRecord = 0;
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LastDataRecordSize = 0;
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LastDataRecordPointer = 0;
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LastOffset = 0;
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int comdatsSoFar = 0;
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// Search for LEDATA, LIDATA and FIXUPP records for this segment
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for (RecNum = 0; RecNum < NumRecords; RecNum++) {
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if (Records[RecNum].Type2 == OMF_LEDATA) {
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// LEDATA record
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Records[RecNum].Index = 3; // Initialize record reading
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Segment = Records[RecNum].GetIndex();// Read segment number
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if ((Segment & 0xC000) == 0x4000) {
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// Refers to Borland communal section
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Segment = (Segment & ~0x4000) + FirstComDatSection - 1;
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}
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if (Segment != SegNum) continue; // Does not refer to this segment
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RecOffset = Records[RecNum].GetNumeric();// Read offset of this record
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RecSize = Records[RecNum].End - Records[RecNum].Index; // Calculate size of data
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LastDataRecord = RecNum; // Save for later FIXUPP that refers to this record
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if (RecOffset < LastOffset + LastDataRecordSize && LastOffset < RecOffset + RecSize) {
|
|
// Overlapping data records
|
|
if (RecOffset + 8 < LastOffset + LastDataRecordSize || Segments[SegNum].Type != 1) {
|
|
// Overlapping data by more than 7 bytes or not executable code
|
|
err.submit(1207);
|
|
}
|
|
else {
|
|
// Possibly backpatched code
|
|
err.submit(1208); // Warning
|
|
err.ClearError(1208); // Report only once
|
|
}
|
|
}
|
|
|
|
LastDataRecordSize = RecSize;
|
|
LastDataRecordPointer = Records[RecNum].buffer + Records[RecNum].FileOffset + Records[RecNum].Index;
|
|
LastOffset = RecOffset; // Save offset for subsequent FIXUPP records
|
|
|
|
// Check if data within segment
|
|
if (RecOffset + RecSize > SegmentSize) {
|
|
err.submit(2309, GetSegmentName(Segment));
|
|
continue;
|
|
}
|
|
|
|
// Put raw data into temporary buffer
|
|
memcpy(TempBuf.Buf() + RecOffset, LastDataRecordPointer, RecSize);
|
|
|
|
} // Finished with LEDATA record
|
|
|
|
if (Records[RecNum].Type2 == OMF_LIDATA) {
|
|
// LIDATA record
|
|
Records[RecNum].Index = 3; // Initialize record reading
|
|
Segment = Records[RecNum].GetIndex();
|
|
|
|
if (Segment != SegNum) continue; // Does not refer to this segment
|
|
|
|
LastDataRecord = RecNum; // Save for later FIXUPP that refers to this record
|
|
|
|
RecOffset = Records[RecNum].GetNumeric();// Read offset
|
|
|
|
if (RecOffset > SegmentSize) {
|
|
err.submit(2310); continue; // Error: outside bounds
|
|
}
|
|
|
|
// Unpack LIDATA blocks recursively
|
|
RecSize = Records[RecNum].UnpackLIDATABlock(TempBuf.Buf() + RecOffset, SegmentSize - RecOffset);
|
|
|
|
if (RecOffset < LastOffset + LastDataRecordSize && LastOffset < RecOffset + RecSize) {
|
|
// Overlapping data records
|
|
err.submit(1207); // Warning
|
|
}
|
|
LastDataRecordSize = RecSize; // Save data size
|
|
LastOffset = RecOffset; // Save offset for subsequent FIXUPP records
|
|
|
|
} // Finished with LIDATA record
|
|
|
|
if (Records[RecNum].Type2 == OMF_COMDAT) {
|
|
// COMDAT record.
|
|
|
|
Records[RecNum].Index = 3; // Initialize record reading
|
|
uint16 flags = Records[RecNum].GetByte();
|
|
if ((flags&1)==0) { // not a continuation
|
|
++comdatsSoFar;
|
|
LastDataRecord = RecNum; // Save for later FIXUPP that refers to this record
|
|
}
|
|
Segment = FirstComDatSection + comdatsSoFar-1;
|
|
if (SegNum != Segment) continue;
|
|
|
|
uint16 attribs = Records[RecNum].GetByte();
|
|
Records[RecNum].GetByte(); // align (ignore)
|
|
RecOffset = Records[RecNum].GetNumeric();
|
|
Records[RecNum].GetIndex(); // type (ignore)
|
|
if ((attribs&0xF)==0) {
|
|
Records[RecNum].GetIndex(); // public base
|
|
uint16 publicSegment = Records[RecNum].GetIndex();
|
|
if (publicSegment==0) Records[RecNum].GetIndex(); // public frame (ignore)
|
|
}
|
|
Records[RecNum].GetIndex(); // public name (ignore)
|
|
RecSize = Records[RecNum].End - Records[RecNum].Index; // Calculate size of data
|
|
|
|
LastDataRecord = RecNum; // Save for later FIXUPP that refers to this record
|
|
LastDataRecordSize = RecSize;
|
|
LastDataRecordPointer = Records[RecNum].buffer + Records[RecNum].Index+Records[RecNum].FileOffset;
|
|
LastOffset = RecOffset;
|
|
// Put raw data into temporary buffer
|
|
memcpy(TempBuf.Buf() + RecOffset, LastDataRecordPointer, RecSize);
|
|
} // Finished with COMDAT record
|
|
|
|
if (Records[RecNum].Type2 == OMF_FIXUPP) {
|
|
// FIXUPP record
|
|
if (Segment != SegNum) continue; // Does not refer to this segment
|
|
Records[RecNum].Index = 3;
|
|
|
|
if (Records[LastDataRecord].Type2 == OMF_LEDATA) {
|
|
// FIXUPP for last LEDATA record
|
|
// Make relocation records
|
|
MakeRelocations(Segment, RecNum, LastOffset, LastDataRecordSize, (uint8*)TempBuf.Buf());
|
|
}
|
|
else if (Records[RecNum].Index < Records[RecNum].End) {
|
|
// Non-empty FIXUPP record does not refer to LEDATA record
|
|
if (Records[LastDataRecord].Type2 == OMF_COMDAT) {
|
|
// FIXUPP for last COMDAT record
|
|
// Make relocation records
|
|
MakeRelocations(Segment, RecNum, LastOffset, LastDataRecordSize, (uint8*)TempBuf.Buf());
|
|
}
|
|
else if (Records[LastDataRecord].Type2 == OMF_LIDATA) {
|
|
err.submit(2311); // Error: Relocation of iterated data not supported
|
|
}
|
|
else {
|
|
err.submit(2312); // Does not refer to data record
|
|
}
|
|
}
|
|
}
|
|
} // End of loop to search for LEDATA, LIDATA and FIXUPP records for this segment
|
|
|
|
// Transfer raw data from TempBuf to SegmentData buffer
|
|
BufOffset = SegmentData.Push(TempBuf.Buf(), SegmentSize);
|
|
|
|
// Remember offset into SegmentData
|
|
Segments[SegNum].BufOffset = BufOffset;
|
|
|
|
} // End of first loop through segments
|
|
|
|
// We must put all segments into SegmentData buffer before we assign pointers to
|
|
// the raw data because otherwise the SegmentData buffer might me reallocated
|
|
// when it grows and the pointers become invalid. This is the reasons why we
|
|
// have two loops through the segments here.
|
|
|
|
// Second loop through segments
|
|
int totalcodesize=0;
|
|
for (SegNum = 1; SegNum <= NumSegments; SegNum++) {
|
|
|
|
// Pointer to merged raw data
|
|
uint8 * RawDatap = (uint8*)SegmentData.Buf() + Segments[SegNum].BufOffset;
|
|
|
|
// Size of raw data
|
|
uint32 InitSize = (Segments[SegNum].Type == 3) ? 0 : Segments[SegNum].Size;
|
|
|
|
// Define segment
|
|
const char * SegmentName = NameBuffer.Buf() + Segments[SegNum].NameO;
|
|
Disasm.AddSection(RawDatap, InitSize, Segments[SegNum].Size, Segments[SegNum].Offset,
|
|
Segments[SegNum].Type, Segments[SegNum].Align, Segments[SegNum].WordSize, SegmentName);
|
|
if (Segments[SegNum].Type == 1 || Segments[SegNum].Type == 0x1001) {
|
|
totalcodesize += Segments[SegNum].Size;
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
// MakeRelocations
|
|
void COMF2ASM::MakeRelocations(int32 Segment, uint32 RecNum, uint32 SOffset, uint32 RSize, uint8 * SData) {
|
|
// Make relocations for object and executable files
|
|
// Parameters:
|
|
// Segment = segment index of last LEDATA record
|
|
// RecNum = FIXUPP record number
|
|
// SOffset = segment relative offset of last LEDATA record
|
|
// RSize = Size of last LEDATA record
|
|
// SData = pointer to raw segment data
|
|
|
|
uint32 Frame, Target, TargetDisplacement; // Contents of FIXUPP record
|
|
uint8 byte1, byte2; // First two bytes of subrecord
|
|
int32 Inline; // Inline address or addend in relocation source
|
|
//int16 InlineSeg; // Segment address stored in relocation source
|
|
int32 Addend; // Correction to add to target address
|
|
int32 SourceSize; // Size of relocation source
|
|
uint32 RelType; // Relocation type, as defined in disasm.h
|
|
int32 TargetSegment; // Target segment or group
|
|
uint32 TargetOffset; // Target offset
|
|
uint32 TargetSymbol; // Symbol index of target
|
|
uint32 ReferenceIndex; // Segment/group index of reference frame
|
|
|
|
// Bitfields in subrecords
|
|
OMF_SLocat Locat; // Structure of first two bytes of FIXUP subrecord swapped = Locat field
|
|
OMF_SFixData FixData; // Structure of FixData field in FIXUP subrecord of FIXUPP record
|
|
OMF_STrdDat TrdDat; // Structure of Thread Data field in THREAD subrecord of FIXUPP record
|
|
|
|
Records[RecNum].Index = 3;
|
|
|
|
// Loop through entries in record
|
|
while (Records[RecNum].Index < Records[RecNum].End) {
|
|
|
|
// Read first byte
|
|
byte1 = Records[RecNum].GetByte();
|
|
if (byte1 & 0x80) {
|
|
|
|
// This is a FIXUP subrecord
|
|
Frame = 0; Target = 0; TargetDisplacement = 0; Addend = 0; ReferenceIndex = 0;
|
|
|
|
// read second byte
|
|
byte2 = Records[RecNum].GetByte();
|
|
// swap bytes and put into byte12 bitfield
|
|
Locat.bytes[1] = byte1;
|
|
Locat.bytes[0] = byte2;
|
|
|
|
// Read FixData
|
|
FixData.b = Records[RecNum].GetByte();
|
|
|
|
// Read conditional fields
|
|
if (FixData.s.F) {
|
|
// Frame specified by previously define thread
|
|
// Does anybody still use compression of repeated fixup targets?
|
|
// I don't care to support this if it is never used
|
|
err.submit(2313); // Error message: not supported
|
|
continue;
|
|
}
|
|
else {
|
|
if (FixData.s.Frame < 4) {
|
|
// Frame datum field present
|
|
Frame = Records[RecNum].GetIndex();
|
|
}
|
|
else Frame = 0;
|
|
|
|
switch (FixData.s.Frame) { // Frame method
|
|
case 0: // F0: segment
|
|
ReferenceIndex = Frame;
|
|
break;
|
|
|
|
case 1: // F1: group
|
|
// Groups defined after segments. Add number of segments to get group index
|
|
ReferenceIndex = Frame + NumSegments;
|
|
break;
|
|
|
|
default:
|
|
case 2: // F2: external symbol
|
|
ReferenceIndex = 0;
|
|
break;
|
|
|
|
case 4: // F4: traget frame = source frame
|
|
Frame = Segment;
|
|
break;
|
|
|
|
case 5: // F5: target frame = target segment
|
|
Frame = 0;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (FixData.s.T == 0) {
|
|
// Target specified
|
|
Target = Records[RecNum].GetIndex();
|
|
if ((Target & 0xC000) == 0x4000) {
|
|
// Refers to Borland communal section
|
|
Target = (Target & ~0x4000) + FirstComDatSection - 1;
|
|
}
|
|
//uint32 TargetMethod = FixData.s.Target + FixData.s.P * 4;
|
|
}
|
|
else {
|
|
// Target specified in previous thread
|
|
// Does anybody still use compression of repeated fixup targets?
|
|
// I don't care to support this if it is never used
|
|
err.submit(2313); // Error message: not supported
|
|
continue;
|
|
}
|
|
|
|
if (FixData.s.P == 0) {
|
|
TargetDisplacement = Records[RecNum].GetNumeric();
|
|
}
|
|
|
|
if (!SData || Locat.s.Offset > RSize) {
|
|
err.submit(2032); // Relocation points outside segment
|
|
return;
|
|
}
|
|
// Get inline addend and check relocation method
|
|
|
|
// Pointer to relocation source inline in raw data:
|
|
uint8 * inlinep = SData + SOffset + Locat.s.Offset;
|
|
Inline = 0; SourceSize = 0;
|
|
//InlineSeg = 0;
|
|
TargetSegment = 0; TargetOffset = 0; TargetSymbol = 0;
|
|
|
|
// Relocation type
|
|
if (Locat.s.M) {
|
|
// Segment relative
|
|
RelType = 8;
|
|
}
|
|
else {
|
|
// (E)IP relative
|
|
RelType = 2;
|
|
}
|
|
|
|
switch (Locat.s.Location) {// Relocation method
|
|
case OMF_Fixup_8bit: // 8 bit
|
|
SourceSize = 1;
|
|
Inline = *(int8*)inlinep;
|
|
break;
|
|
|
|
case OMF_Fixup_16bit: // 16 bit
|
|
SourceSize = 2;
|
|
Inline = *(int16*)inlinep;
|
|
break;
|
|
|
|
case OMF_Fixup_32bit: // 32 bit
|
|
SourceSize = 4;
|
|
Inline = *(int32*)inlinep;
|
|
break;
|
|
|
|
case OMF_Fixup_Far: // far 16+16 bit
|
|
RelType = 0x400;
|
|
SourceSize = 4;
|
|
Inline = *(int16*)inlinep;
|
|
break;
|
|
|
|
case OMF_Fixup_Farword: // far 32+16 bit
|
|
case OMF_Fixup_Pharlab48:
|
|
RelType = 0x400;
|
|
SourceSize = 6;
|
|
Inline = *(int32*)inlinep;
|
|
break;
|
|
|
|
case OMF_Fixup_Segment: // segment selector
|
|
if (TargetDisplacement || FixData.s.Target == 2) {
|
|
// An offset is specified or an external symbol.
|
|
// Segment of symbol is required (seg xxx)
|
|
RelType = 0x200;
|
|
}
|
|
else {
|
|
// A segment name or group name is required
|
|
RelType = 0x100;
|
|
};
|
|
SourceSize = 2;
|
|
Inline = *(int16*)inlinep;
|
|
break;
|
|
|
|
case OMF_Fixup_16bitLoader: // 16-bit loader resolved
|
|
RelType = 0x21;
|
|
SourceSize = 2;
|
|
Inline = *(int16*)inlinep;
|
|
break;
|
|
|
|
case OMF_Fixup_32bitLoader: // 32-bit loader resolved
|
|
RelType = 0x21;
|
|
SourceSize = 4;
|
|
Inline = *(int32*)inlinep;
|
|
break;
|
|
|
|
default: // unknown or not supported
|
|
RelType = 0;
|
|
SourceSize = 0;
|
|
Inline = 0;
|
|
} // end switch
|
|
|
|
|
|
// Offset of relocation source
|
|
uint32 SourceOffset = SOffset + Locat.s.Offset;
|
|
|
|
// Relocation type: direct or (E)IP-relative
|
|
if (RelType == 2) {
|
|
// (E)IP-relative
|
|
// Correct for difference between source address and end of instruction
|
|
Addend = -SourceSize;
|
|
}
|
|
|
|
// Check target method
|
|
switch (FixData.s.Target) { // = Target method modulo 4
|
|
case 0: // T0 and T4: Target = segment
|
|
// Local or public symbol
|
|
TargetSegment = Target; // Target segment
|
|
TargetOffset = TargetDisplacement; // Target offset
|
|
if (RelType != 0x100) {
|
|
// Add inline to target address, except if target is a segment only
|
|
TargetOffset += Inline;
|
|
Addend -= Inline; // Avoid adding Inline twice
|
|
}
|
|
break;
|
|
|
|
case 1: // T1 and T5: Target = segment group
|
|
// Warning: this method has not occurred. Not tested!
|
|
// Groups are numbered in sequence after segments in Disasm. Add number of segments to group index
|
|
TargetSegment = Target + NumSegments;// Target group
|
|
TargetOffset = TargetDisplacement; // Target offset
|
|
if (RelType != 0x100) {
|
|
// Add inline to target address, except if target is a segment only
|
|
TargetOffset += Inline;
|
|
Addend -= Inline; // Avoid adding Inline twice
|
|
}
|
|
break;
|
|
|
|
case 2: // T2 and T6: Target = external symbol
|
|
// Translate old EXTDEF index to new symbol table index
|
|
if (Target < ExtdefTranslation.GetNumEntries()) {
|
|
TargetSymbol = ExtdefTranslation[Target];
|
|
}
|
|
break;
|
|
|
|
default: // Unknown method
|
|
err.submit(2314, FixData.s.Target + FixData.s.P * 4);
|
|
}
|
|
|
|
if (TargetSymbol == 0) {
|
|
// Make symbol record for target
|
|
TargetSymbol = Disasm.AddSymbol(TargetSegment, TargetOffset, 0, 0, 2, 0, 0);
|
|
}
|
|
|
|
if (FixData.s.Frame == 4 && FixData.s.Target + FixData.s.P*4 == 6) {
|
|
// Note:
|
|
// Frame method F4 is apparently used by 16-bit Borland compiler for
|
|
// indicating floating point instructions that can be emulated if no
|
|
// 8087 processor is present. I can't find this documented anywhere.
|
|
// I don't know what the exact criterion is for indicating that a FIXUP
|
|
// subrecord is not a relocation record but a f.p. emulating record.
|
|
// I have chosen to consider all subrecords with frame method F4 and
|
|
// target method T6 to be ignored.
|
|
;
|
|
}
|
|
else {
|
|
// This is a proper relocation subrecord
|
|
Disasm.AddRelocation(Segment, SourceOffset, Addend, RelType, SourceSize, TargetSymbol, ReferenceIndex);
|
|
}
|
|
}
|
|
else {
|
|
// This is a THREAD subrecord.
|
|
// I don't think this feature for compressing fixup data is
|
|
// used any more, if it ever was. I am not supporting it here.
|
|
// Frame threads can be safely ignored. A target thread cannot
|
|
// be ignored if there is any reference to it. The error is
|
|
// reported above at the reference to a target thread, not here.
|
|
TrdDat.b = byte1; // Put byte into bitfield
|
|
if (TrdDat.s.Method < 4) { // Make sure we read this correctly, even if ignored
|
|
Records[RecNum].GetIndex(); // has index field if method < 4 ?
|
|
}
|
|
}
|
|
} // Finished loop through subrecords
|
|
|
|
if (Records[RecNum].Index != Records[RecNum].End) err.submit(1203); // Check for consistency
|
|
}
|