80 lines
1.6 KiB
C
80 lines
1.6 KiB
C
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// vmm.c
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// Author: Josh Holtrop
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// Date: 09/30/03
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// Rewritten from scratch: 12/23/03
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void vmm_init()
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{
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dword *pageTables = (dword *)0xC0104000; //this is the location of the page directory
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pageTables[0x3FF] = 0x104000|0x03; //the last page directory entry points to the page directory itself
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if (videoMode) //we are in a graphical mode
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{
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dword vidPages = video_mode.XResolution * video_mode.YResolution * (video_mode.BitsPerPixel >> 3);
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if (vidPages % 4096)
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vidPages = (vidPages >> 12) + 1;
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else
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vidPages = (vidPages >> 12);
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vmm_mapn(0xF0000000, video_mode.PhysBasePtr, vidPages);
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}
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}
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void vmm_map1(dword virt, dword physical)
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{
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dword pde = virt >> 22;
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dword pte = (virt & 0x003FF000) >> 12;
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dword *pageTables = (dword *)0xC0104000; //this is the location of the page directory
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if (!(pageTables[pde] & 0x01)) //the page directory entry does not exist, we must allocate a page for it
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{
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dword *newpagetable = mm_palloc();
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pageTables[pde] = ((dword)newpagetable) | 0x03;
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invlpg(virt);
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dword *newpteptr = (dword *)(0xFFC00000 | (pde << 12)); //points to first dword of newly allocated page table
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int a;
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for (a = 0; a < 1024; a++)
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{
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newpteptr[a] = 0;
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}
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}
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dword *pteptr = (dword *)(0xFFC00000 | (pde << 12) | (pte << 2));
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*pteptr = physical | 0x03;
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}
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void vmm_mapn(dword virt, dword physical, dword n)
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{
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for (; n > 0; n--)
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{
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vmm_map1(virt, physical);
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virt += 4096;
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physical += 4096;
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}
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}
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void *malloc(dword bytes)
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{
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}
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int free(void *ptr)
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{
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}
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