fix_emu.c 1.4 KB

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  1. /* fix_emu.c: Routines for emulator-specific M68000 code fixup
  2. Copyright (C) 2003 Sebastian Reichelt
  3. This program is free software; you can redistribute it and/or modify
  4. it under the terms of the GNU General Public License as published by
  5. the Free Software Foundation; either version 2, or (at your option)
  6. any later version.
  7. This program is distributed in the hope that it will be useful,
  8. but WITHOUT ANY WARRANTY; without even the implied warranty of
  9. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  10. GNU General Public License for more details.
  11. You should have received a copy of the GNU General Public License
  12. along with this program; if not, write to the Free Software Foundation,
  13. Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
  14. #include "fix_emu.h"
  15. #include "emu.h"
  16. #include "../manip.h"
  17. // Turn an M68000 absolute JRA/JSR to a program-relative F-Line jump.
  18. void M68kEmuMakeFLineJump (RELOC *Reloc, I1 *Opcode, BOOLEAN IsJSR)
  19. {
  20. if ((Reloc->Size == 4) && (!(Reloc->Relative)))
  21. {
  22. // Optimize the JRA or JSR into an F-Line JMP.W or JSR.W.
  23. Opcode [0] = (IsJSR ? M68K_EMU_JSR_W_0 : M68K_EMU_JMP_W_0);
  24. Opcode [1] = (IsJSR ? M68K_EMU_JSR_W_1 : M68K_EMU_JMP_W_1);
  25. // Change the reloc to 2-byte program-relative.
  26. SetRelocProgramRelative (Reloc);
  27. Reloc->Size = 2;
  28. Reloc->FixedOffset -= 0x8000;
  29. }
  30. }