trunk/src/emu/cpu/m68000/m68kmmu.h
| r29585 | r29586 | |
|---|
| 625 | 625 | // is UDT marked valid? |
| 626 | 626 | if (root_entry & 2) |
| 627 | 627 | { |
| 628 | // we're accessing through this root entry, so set the U bit |
| 629 | if ((!(root_entry & 0x8)) && (!ptest)) |
| 630 | { |
| 631 | root_entry |= 0x8; |
| 632 | m68k->program->write_dword(root_ptr, root_entry); |
| 633 | } |
| 634 | |
| 635 | // PTEST: any write protect bits set in the search tree will set W in SR |
| 636 | if ((ptest) && (root_entry & 4)) |
| 637 | { |
| 638 | m68k->mmu_tmp_sr |= 4; |
| 639 | } |
| 640 | |
| 628 | 641 | pointer_ptr = (root_entry & ~0x1ff) + (ptr_idx<<2); |
| 629 | 642 | pointer_entry = m68k->program->read_dword(pointer_ptr); |
| 630 | 643 | |
| 644 | // PTEST: any write protect bits set in the search tree will set W in SR |
| 645 | if ((ptest) && (pointer_entry & 4)) |
| 646 | { |
| 647 | m68k->mmu_tmp_sr |= 4; |
| 648 | } |
| 649 | |
| 650 | // update U bit on this pointer entry too |
| 651 | if ((!(pointer_entry & 0x8)) && (!ptest)) |
| 652 | { |
| 653 | pointer_entry |= 0x8; |
| 654 | m68k->program->write_dword(pointer_ptr, pointer_entry); |
| 655 | } |
| 656 | |
| 631 | 657 | // logerror("pointer entry = %08x\n", pointer_entry); |
| 632 | 658 | |
| 633 | 659 | // write protected by the root or pointer entries? |
| r29585 | r29586 | |
|---|
| 682 | 708 | page_idx = (addr_in >> 13) & 0x1f; |
| 683 | 709 | page = addr_in & 0x1fff; |
| 684 | 710 | pointer_entry &= ~0x7f; |
| 685 | | |
| 686 | 711 | // logerror("8k pages: index %x page %x\n", page_idx, page); |
| 687 | 712 | } |
| 688 | 713 | else // 4k pages |
| r29585 | r29586 | |
|---|
| 690 | 715 | page_idx = (addr_in >> 12) & 0x3f; |
| 691 | 716 | page = addr_in & 0xfff; |
| 692 | 717 | pointer_entry &= ~0xff; |
| 693 | | |
| 694 | 718 | // logerror("4k pages: index %x page %x\n", page_idx, page); |
| 695 | 719 | } |
| 696 | 720 | |
| 697 | 721 | page_ptr = pointer_entry + (page_idx<<2); |
| 698 | 722 | page_entry = m68k->program->read_dword(page_ptr); |
| 723 | m68k->mmu_last_page_entry_addr = page_ptr; |
| 699 | 724 | |
| 700 | 725 | // logerror("page_entry = %08x\n", page_entry); |
| 701 | 726 | |
| r29585 | r29586 | |
|---|
| 703 | 728 | while ((page_entry & 3) == 2) |
| 704 | 729 | { |
| 705 | 730 | page_entry = m68k->program->read_dword(page_entry & ~0x3); |
| 731 | m68k->mmu_last_page_entry_addr = (page_entry & ~0x3); |
| 706 | 732 | } |
| 733 | m68k->mmu_last_page_entry = page_entry; |
| 707 | 734 | |
| 708 | 735 | // is the page write protected or supervisor protected? |
| 709 | 736 | if ((((page_entry & 4) && !m68k->mmu_tmp_rw) || ((page_entry & 0x80) && !(fc&4))) && !ptest) |
| r29585 | r29586 | |
|---|
| 745 | 772 | addr_out = (page_entry & ~0xfff) | page; |
| 746 | 773 | } |
| 747 | 774 | |
| 775 | if (!(ptest)) |
| 776 | { |
| 777 | page_entry |= 0x8; // always set the U bit |
| 748 | 778 | |
| 749 | | break; |
| 779 | // if we're writing, the M bit comes into play |
| 780 | if (!m68k->mmu_tmp_rw) |
| 781 | { |
| 782 | page_entry |= 0x10; // set Modified |
| 783 | } |
| 750 | 784 | |
| 785 | // if these updates resulted in a change, write the entry back where we found it |
| 786 | if (page_entry != m68k->mmu_last_page_entry) |
| 787 | { |
| 788 | m68k->mmu_last_page_entry = page_entry; |
| 789 | m68k->program->write_dword(m68k->mmu_last_page_entry_addr, m68k->mmu_last_page_entry); |
| 790 | } |
| 791 | } |
| 792 | else |
| 793 | { |
| 794 | // page entry: UR G U1 U0 S CM CM M U W PDT |
| 795 | // SR: B G U1 U0 S CM CM M 0 W T R |
| 796 | m68k->mmu_tmp_sr |= ((addr_out & ~0xfff) || (page_entry & 0x7f4)); |
| 797 | } |
| 798 | break; |
| 799 | |
| 751 | 800 | case 2: // shouldn't happen |
| 752 | 801 | fatalerror("68040: got indirect final page pointer, shouldn't be possible\n"); |
| 753 | 802 | break; |