134 lines
5.7 KiB
Plaintext
134 lines
5.7 KiB
Plaintext
readme for interpreted thunks
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Interpreted Thunks are an attempt to replace the simplest thunk functions
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in WOW with a bit of data. Each thunk consists of a pointer to the Win32
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API routine (actually to a callable loader thunk in one of the pages set
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aside for fixups if needed) and a pointer to a variable-length byte stream
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which dictates how to convert arguments and return values. The first byte
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is an opcode indicating how to thunk the leftmost argument, the last byte
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is distinguished by having its high bit set (0x8?) and indicates how to
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thunk the return value.
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A tool called genwowit reads a source file called wow.it which contains
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psuedo-prototypes (really thunk descriptions) and generates wowit.h
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and wowit.c with the actualy thunk table and assiociated instruction
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"swamp" containing all the bytecode instruction streams. See
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\nt\private\sdktools\genwowit\readme.txt for details.
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Note that the major restriction of interpreted thunks as implemented is
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that pointers to structures which need thunking are not supported.
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Here's a tiny wow.it and the wowit.h and wowit.c that result.
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----- wow.it begin
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INT UpdateColors(HGDI);
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INT StartPage(HGDI);
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INT EndPage(HGDI);
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DWORD GetFontData(HGDI, DWORD, DWORD, PTR, DWORD);
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WORD GetRasterizerCaps(PTR, INT);
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WORD IsGDIObject=GetObjectType(HGDI);
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WORD GetTextAlign(HGDI);
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INT GetTextCharacterExtra(HGDI);
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INT SetTextCharacterExtra(HGDI, INT);
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DWORD GetTextColor(HGDI);
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INT GetTextFace(HGDI, INT, PTR);
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INT SetTextJustification(HGDI, INT, INT);
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WORD TextOut(HGDI, INT, INT, PTR, INT);
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----- wow.it end
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here's the output genwowit produces on the console:
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Generated wowit.h and wowit.c from wow.it
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13 thunks, 8 unique instruction streams, 29 instruction bytes, 5 max args.
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And the files:
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----- wowit.h begin
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//
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// wowit.h generated by genwowit.exe from wow.it, DO NOT EDIT.
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//
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#include "intthunk.h"
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#define MAX_IT_ARGS 5
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#define IT_WORD ( (UCHAR) 0x0 )
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#define IT_INT ( (UCHAR) 0x1 )
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#define IT_DWORD ( (UCHAR) 0x2 )
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#define IT_LPDWORD ( (UCHAR) 0x3 )
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#define IT_PTR ( (UCHAR) 0x4 )
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#define IT_PTRORATOM ( (UCHAR) 0x5 )
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#define IT_HGDI ( (UCHAR) 0x6 )
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#define IT_HUSER ( (UCHAR) 0x7 )
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#define IT_COLOR ( (UCHAR) 0x8 )
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#define IT_HINST ( (UCHAR) 0x9 )
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#define IT_HICON ( (UCHAR) 0xa )
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#define IT_16ONLY ( (UCHAR) 0xb )
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#define IT_32ONLY ( (UCHAR) 0xc )
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#define IT_RETMASK ( (UCHAR) 0x80 )
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#define IT_DWORDRET ( IT_RETMASK | (UCHAR) 0x0 )
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#define IT_WORDRET ( IT_RETMASK | (UCHAR) 0x1 )
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#define IT_INTRET ( IT_RETMASK | (UCHAR) 0x2 )
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#define IT_HGDIRET ( IT_RETMASK | (UCHAR) 0x3 )
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#define IT_HUSERRET ( IT_RETMASK | (UCHAR) 0x4 )
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#define IT_ZERORET ( IT_RETMASK | (UCHAR) 0x5 )
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#define IT_HICONRET ( IT_RETMASK | (UCHAR) 0x6 )
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#define IT_ONERET ( IT_RETMASK | (UCHAR) 0x7 )
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#define IT_HPRNDWPRET ( IT_RETMASK | (UCHAR) 0x8 )
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#define ITID_UpdateColors 0
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#define ITID_StartPage 1
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#define ITID_EndPage 2
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#define ITID_GetFontData 3
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#define ITID_GetRasterizerCaps 4
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#define ITID_IsGDIObject 5
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#define ITID_GetTextAlign 6
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#define ITID_GetTextCharacterExtra 7
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#define ITID_SetTextCharacterExtra 8
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#define ITID_GetTextColor 9
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#define ITID_GetTextFace 10
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#define ITID_SetTextJustification 11
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#define ITID_TextOut 12
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#define ITID_MAX 12
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----- wowit.h end
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----- wowit.c begin
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//
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// wowit.c generated by genwowit.exe from wow.it, DO NOT EDIT.
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//
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#include "precomp.h"
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#pragma hdrstop
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#define WOWIT_C
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#include "wowit.h"
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CONST BYTE InstrSwamp[] = {
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/* 0 0x0 */ IT_HGDI, IT_INTRET,
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/* 1 0x2 */ IT_HGDI, IT_DWORD, IT_DWORD, IT_PTR, IT_DWORD, IT_DWORDRET,
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/* 2 0x8 */ IT_HGDI, IT_INT, IT_INT, IT_PTR, IT_INT, IT_WORDRET,
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/* 3 0xe */ IT_HGDI, IT_WORDRET,
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/* 4 0x10 */ IT_HGDI, IT_INT, IT_INTRET,
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/* 5 0x13 */ IT_HGDI, IT_DWORDRET,
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/* 6 0x15 */ IT_HGDI, IT_INT, IT_PTR, IT_INTRET,
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/* 7 0x19 */ IT_HGDI, IT_INT, IT_INT, IT_INTRET,
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};
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INT_THUNK_TABLEENTRY IntThunkTable[] = {
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/* 0 */ { (FARPROC) UpdateColors, InstrSwamp + 0x0 }, /* 0 */
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/* 1 */ { (FARPROC) StartPage, InstrSwamp + 0x0 }, /* 0 */
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/* 2 */ { (FARPROC) EndPage, InstrSwamp + 0x0 }, /* 0 */
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/* 3 */ { (FARPROC) GetFontData, InstrSwamp + 0x2 }, /* 1 */
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/* 4 */ { (FARPROC) GetRasterizerCaps, InstrSwamp + 0xb }, /* 2 + 3 */
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/* 5 */ { (FARPROC) GetObjectType, InstrSwamp + 0xe }, /* 3 */
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/* 6 */ { (FARPROC) GetTextAlign, InstrSwamp + 0xe }, /* 3 */
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/* 7 */ { (FARPROC) GetTextCharacterExtra, InstrSwamp + 0x0 }, /* 0 */
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/* 8 */ { (FARPROC) SetTextCharacterExtra, InstrSwamp + 0x10 }, /* 4 */
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/* 9 */ { (FARPROC) GetTextColor, InstrSwamp + 0x13 }, /* 5 */
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/* 10 */ { (FARPROC) GetTextFace, InstrSwamp + 0x15 }, /* 6 */
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/* 11 */ { (FARPROC) SetTextJustification, InstrSwamp + 0x19 }, /* 7 */
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/* 12 */ { (FARPROC) TextOut, InstrSwamp + 0x8 }, /* 2 */
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};
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----- wowit.c end
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