Tue, 15 Jan 2013 17:02:56 +0000
Implement m68k_read_disassembler_* properly
The previous implementations of m68k_read_disassembler are unsuitable due to
interactions with the memory mapper. A read from memory by the DASM should not
mutate system state.
So we modify the m68k_read_disassembler_{8,16,32} functions to do the memory
mapping themselves without causing page faults (bus error exception) or
updating the page flag bits (which could really upset the kernel).
Now all we need is a debugger/disassembler...
| philpem@40 | 1 | #ifndef _MEMORY_H |
| philpem@40 | 2 | #define _MEMORY_H |
| philpem@40 | 3 | |
| philpem@40 | 4 | /*********************************** |
| philpem@40 | 5 | * Array read/write utility macros |
| philpem@40 | 6 | * "Don't Repeat Yourself" :) |
| philpem@40 | 7 | ***********************************/ |
| philpem@40 | 8 | |
| philpem@40 | 9 | /// Array read, 32-bit |
| philpem@40 | 10 | #define RD32(array, address, andmask) \ |
| philpem@40 | 11 | (((uint32_t)array[(address + 0) & (andmask)] << 24) | \ |
| philpem@40 | 12 | ((uint32_t)array[(address + 1) & (andmask)] << 16) | \ |
| philpem@40 | 13 | ((uint32_t)array[(address + 2) & (andmask)] << 8) | \ |
| philpem@40 | 14 | ((uint32_t)array[(address + 3) & (andmask)])) |
| philpem@40 | 15 | |
| philpem@40 | 16 | /// Array read, 16-bit |
| philpem@40 | 17 | #define RD16(array, address, andmask) \ |
| philpem@40 | 18 | (((uint32_t)array[(address + 0) & (andmask)] << 8) | \ |
| philpem@40 | 19 | ((uint32_t)array[(address + 1) & (andmask)])) |
| philpem@40 | 20 | |
| philpem@40 | 21 | /// Array read, 8-bit |
| philpem@40 | 22 | #define RD8(array, address, andmask) \ |
| philpem@40 | 23 | ((uint32_t)array[(address + 0) & (andmask)]) |
| philpem@40 | 24 | |
| philpem@40 | 25 | /// Array write, 32-bit |
| philpem@70 | 26 | #define WR32(array, address, andmask, value) do { \ |
| philpem@40 | 27 | array[(address + 0) & (andmask)] = (value >> 24) & 0xff; \ |
| philpem@40 | 28 | array[(address + 1) & (andmask)] = (value >> 16) & 0xff; \ |
| philpem@40 | 29 | array[(address + 2) & (andmask)] = (value >> 8) & 0xff; \ |
| philpem@40 | 30 | array[(address + 3) & (andmask)] = value & 0xff; \ |
| philpem@70 | 31 | } while (0) |
| philpem@40 | 32 | |
| philpem@40 | 33 | /// Array write, 16-bit |
| philpem@70 | 34 | #define WR16(array, address, andmask, value) do { \ |
| philpem@40 | 35 | array[(address + 0) & (andmask)] = (value >> 8) & 0xff; \ |
| philpem@40 | 36 | array[(address + 1) & (andmask)] = value & 0xff; \ |
| philpem@70 | 37 | } while (0) |
| philpem@40 | 38 | |
| philpem@40 | 39 | /// Array write, 8-bit |
| philpem@70 | 40 | #define WR8(array, address, andmask, value) do { \ |
| philpem@70 | 41 | array[(address + 0) & (andmask)] = value & 0xff; \ |
| philpem@70 | 42 | } while (0) |
| philpem@40 | 43 | |
| philpem@40 | 44 | /****************** |
| philpem@40 | 45 | * Memory mapping |
| philpem@40 | 46 | ******************/ |
| philpem@40 | 47 | |
| philpem@40 | 48 | typedef enum { |
| philpem@40 | 49 | MEM_ALLOWED = 0, |
| philpem@40 | 50 | MEM_PAGEFAULT, // Page fault -- page not present |
| philpem@40 | 51 | MEM_PAGE_NO_WE, // Page not write enabled |
| philpem@40 | 52 | MEM_KERNEL, // User attempted to access kernel memory |
| philpem@40 | 53 | MEM_UIE // User Nonmemory Location Access |
| philpem@40 | 54 | } MEM_STATUS; |
| philpem@40 | 55 | |
| philpem@40 | 56 | /** |
| philpem@40 | 57 | * @brief Check memory access permissions for a given address. |
| philpem@40 | 58 | * @param addr Address. |
| philpem@40 | 59 | * @param writing true if writing to memory, false if reading. |
| philpem@40 | 60 | * @return One of the MEM_STATUS constants, specifying whether the access is |
| philpem@40 | 61 | * permitted, or what error occurred. |
| philpem@40 | 62 | */ |
| philpem@40 | 63 | MEM_STATUS checkMemoryAccess(uint32_t addr, bool writing); |
| philpem@40 | 64 | |
| philpem@40 | 65 | /** |
| philpem@40 | 66 | * @brief Map a CPU memory address into physical memory space. |
| philpem@40 | 67 | * @param addr Address. |
| philpem@40 | 68 | * @param writing true if writing to memory, false if reading. |
| philpem@40 | 69 | * @return Address, remapped into physical memory. |
| philpem@40 | 70 | */ |
| philpem@40 | 71 | uint32_t mapAddr(uint32_t addr, bool writing); |
| philpem@40 | 72 | |
| philpem@112 | 73 | /** |
| philpem@112 | 74 | * @brief Check access flags for a DMA transfer and trigger an exception if |
| philpem@112 | 75 | * the access is not permitted |
| philpem@112 | 76 | * @param reading true if reading from memory, false if writing |
| philpem@112 | 77 | * @return true if the access is permitted, false if not |
| philpem@112 | 78 | */ |
| philpem@112 | 79 | bool access_check_dma(int reading); |
| philpem@112 | 80 | |
| philpem@40 | 81 | #endif |