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smd_ida_tools2

The IDA Pro tools for the Sega Genesis/MegaDrive romhackers

Contains

  1. ROM files loader
  2. Z80 sound drivers loader
  3. IDA Pro debugger for Sega Mega Drive/Genesis roms and Z80 sound drivers

How to compile

  1. Edit paths to your IDA/SDK installation according to your real paths (IDA_DIR, IDA_SDK)
  2. Install vcpkg as described in the Tutorial: Install and use packages with MSBuild in Visual Studio step 1.
  3. Download and unpack IDA Pro QT distro: qt-5.15.2-full-IDA83.tar.bz2
  4. Install Perl from: https://strawberryperl.com/
  5. Edit build.py from IDA Pro QT distro. Add: "-nomake", "examples", after "-nomake", "tests",
  6. Install and add to PATH jom from: https://ftp.funet.fi/pub/mirrors/download.qt-project.org/official_releases/jom/jom_1_1_4.zip
  7. Build IDA Pro QT (using Visual Studio Developement Command Prompt): python build.py -j 16 -v
  8. Compile solution with Visual Studio 2022 or newer

How to use

  1. Put files from the loaders dir into the corresponding IDA folder
  2. Put files from the plugins dir into the corresponding IDA folder
  3. Open ROM in IDA
  4. Choose GensIDA debugger plugin or Z80 debugger plugin debugger
  5. Press F9 to start a debugging process
  6. Run gens_68k.exe or gens_z80.exe from gens folder, choose a ROM
  7. Debug!

Available assemblers

image

How to produce a compilable asm listing

  1. Press Shift+J to choose how to mark your data range. Or mark it by yourself using available methods (listed below)
  2. Press File->Produce file->Create LST file.... Save .lst listing file
  3. Use any of AS/VASM/ASM68K assemblers to compile your .lst file. You can also use assemble_as.bat, assemble_vasm.bat or assemble_asm68k.bat for that

image

Data marking methods

All methods are specified like START_TAG - END_TAG (except ORG tag), where START_TAG must be specified using Anterior comment (Ins) at the first line of your data, and END_TAG must be inserted using Posterior comment (Shift+Ins).

Available TAGS:

  1. BIN "relative/path.bin". This tag allows you to save some data array (or even code) to the "relative/path.bin" during the extraction. It also inserts binclude "relative/path.bin" line to your listing.
  2. INC_START "relative/path.inc" - INC_END. The same as the previous item, except it just stores copies all lines between these tags as is and inserts the following line: include "relative/path.inc".
  3. DEL_START - DEL_END. These tags can be used if you want to cut some lines from the resulting asm listing.
  4. ORG $SIZE. This tag inserts org $size directive line in the output.

How To Set Read Write Breakpoints On VDP VRAM, VDP CRAM, VDP VSRAM

NOTE: this works for DMA operations as well.

Once you are debugging, in the IDA View click 'g' and go to either:

Memory type Address Alternative address
VRAM 0x00D00000 DBG_VDP_VRAM:00D00000
CRAM 0x00D10000 DBG_VDP_CRAM:00D10000
VSRAM 0x00D20000 DBG_VDP_VSRAM:00D20000

Find the address or addresses you want, offsetted from the above. Then select it / them . Right click. a prompt will come up. Click "Add Beakpoint" , or press F2 after selecting. A "Breakpoint Settings" window will come up. Select either read or write or both under Hardware breakpoint mode and set the size. You can enable other settings like actions etc.

Debugger in IDA PRO

General Registers can be seen while running the debugger in IDA Pro by going to Debugger -> Debugger Windows -> General Registers. D0-D7, A0-A7, PC, SP, SR, DMA_LEN, DMA_SRC and VDP_DST are all shown here

VDP Registers can be seen while running the debugger in IDA pro by doign to Debugger -> Debugger Windows -> VDP Registers

Launch without debugging

Pass -nodebug 1 to gens_xxx.exe.