src/memory.h

Sat, 17 Nov 2012 19:18:29 +0000

author
Philip Pemberton <philpem@philpem.me.uk>
date
Sat, 17 Nov 2012 19:18:29 +0000
changeset 112
a392eb8f9806
parent 70
5bbe76e71698
child 128
3246b74d96bc
child 150
c19afa2c81db
permissions
-rw-r--r--

add HDD support + fixes

Patch-Author: Andrew Warkentin <andreww591!gmail>
Patch-Message-ID: <50A772FC.8020009@gmail.com>

I have added floppy write support, full hard disk emulation, and proper handling of DMA page faults to FreeBee. I also fixed the floppy step commands, changed the "force interrupt" floppy command to generate a type 1 status, and changed the DMA address counter to reset to 3fff when a transfer completes (which is what Unix seems to expect - without it, the kernel says that the floppy isn't ready). The floppy, hard disk, and DMA page fault tests all pass. Initializing hard disks and floppies also works (the geometry for both is still fixed by the size of the image, though, and format commands only appear to succeed, but they don't modify the image). Unix still doesn't run, though (it hangs after reading some sectors from the floppy).

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