| 1518,3 → 1518,72 |
|---|
| ret |
| endp |
| |
| |
| |
| proc user_ring stdcall, size:dword |
| |
| locals |
| virt_ptr dd ? |
| phys_ptr dd ? |
| num_pages dd ? |
| endl |
| |
| ; Size must be an exact multiple of pagesize |
| mov eax, size |
| test eax, PAGE_SIZE-1 |
| jnz .exit |
| |
| ; We must have at least one complete page |
| shr eax, 12 |
| jz .exit |
| mov [num_pages], eax |
| |
| ; Allocate double the virtual memory |
| mov eax, [size] |
| shl eax, 1 |
| jz .exit |
| stdcall user_alloc, eax |
| test eax, eax |
| jz .exit |
| mov [virt_ptr], eax |
| |
| ; Now allocate physical memory |
| stdcall alloc_pages, [num_pages] |
| test eax, eax |
| jz .exit_free_virt |
| mov [phys_ptr], eax |
| |
| ; Map first half of virtual memory to physical memory |
| push ecx esi edi |
| mov ecx, [num_pages] |
| mov esi, [virt_ptr] |
| mov edi, [phys_ptr] |
| .loop1: |
| stdcall map_page, esi, edi, PG_UWR |
| add esi, PAGE_SIZE |
| add edi, PAGE_SIZE |
| dec ecx |
| jnz .loop1 |
| |
| ; Map second half of virtual memory to same physical memory |
| mov ecx, [pages] |
| mov edi, [phys_ptr] |
| .loop2: |
| stdcall map_page, esi, edi, PG_UWR |
| add esi, PAGE_SIZE |
| add edi, PAGE_SIZE |
| dec ecx |
| jnz .loop2 |
| pop edi esi ecx |
| |
| mov eax, [virt_ptr] |
| ret |
| |
| .exit_free_virt: |
| stdcall user_free, [virt_ptr] |
| |
| .exit: |
| xor eax, eax |
| ret |
| |
| endp |