Details | Last modification | View Log | RSS feed
| Rev | Author | Line No. | Line |
|---|---|---|---|
| 2 | pj | 1 | /* Project: OSLib |
| 2 | * Description: The OS Construction Kit |
||
| 3 | * Date: 1.6.2000 |
||
| 4 | * Idea by: Luca Abeni & Gerardo Lamastra |
||
| 5 | * |
||
| 6 | * OSLib is an SO project aimed at developing a common, easy-to-use |
||
| 7 | * low-level infrastructure for developing OS kernels and Embedded |
||
| 8 | * Applications; it partially derives from the HARTIK project but it |
||
| 9 | * currently is independently developed. |
||
| 10 | * |
||
| 11 | * OSLib is distributed under GPL License, and some of its code has |
||
| 12 | * been derived from the Linux kernel source; also some important |
||
| 13 | * ideas come from studying the DJGPP go32 extender. |
||
| 14 | * |
||
| 15 | * We acknowledge the Linux Community, Free Software Foundation, |
||
| 16 | * D.J. Delorie and all the other developers who believe in the |
||
| 17 | * freedom of software and ideas. |
||
| 18 | * |
||
| 19 | * For legalese, check out the included GPL license. |
||
| 20 | */ |
||
| 21 | |||
| 22 | /* This file contains the DOS memory allocator */ |
||
| 23 | |||
| 24 | #include <ll/i386/mem.h> |
||
| 25 | #include <ll/i386/x-bios.h> |
||
| 26 | #include <ll/i386/x-dosmem.h> |
||
| 27 | #include <ll/i386/error.h> |
||
| 28 | |||
| 29 | FILE(X - Dos - Memory); |
||
| 30 | |||
| 31 | /* |
||
| 32 | We do not use the standard K&R pointer based memory allocator! |
||
| 33 | This is because we cannot do pointer tricks easily with the GCC |
||
| 34 | which only handles explicitely 32 bit non segmented address space. |
||
| 35 | So we cannot use far pointers, and we cannot chain buckets of memory |
||
| 36 | which are located in low memory area, beyond the accessibility |
||
| 37 | of the ELF address space. |
||
| 38 | A static allocation is so preferred; this should not give trouble |
||
| 39 | since DOS memory is only used for reflection related purposes |
||
| 40 | */ |
||
| 41 | |||
| 42 | #define MAX_PARTITION 50 /* Max available partition */ |
||
| 43 | |||
| 44 | static struct { |
||
| 45 | BYTE used; |
||
| 46 | LIN_ADDR addr; |
||
| 47 | DWORD size; |
||
| 48 | } mem_table[MAX_PARTITION]; |
||
| 49 | |||
| 50 | static int inited = 0; |
||
| 51 | |||
| 52 | void DOS_dump_mem(void) |
||
| 53 | { |
||
| 54 | register int i; |
||
| 55 | for (i = 0; i < MAX_PARTITION; i++) { |
||
| 56 | if (mem_table[i].used) |
||
| 57 | message("(%d) Addr : %p Size : %lu/%lx\n", |
||
| 58 | i, mem_table[i].addr, |
||
| 59 | mem_table[i].size, mem_table[i].size); |
||
| 60 | } |
||
| 61 | } |
||
| 62 | |||
| 63 | void DOS_mem_init(void) |
||
| 64 | { |
||
| 65 | register int i; |
||
| 66 | |||
| 67 | if (inited == 0) { |
||
| 68 | mem_table[0].used = TRUE; |
||
| 69 | X_meminfo(NULL, NULL, &(mem_table[0].addr), &(mem_table[0].size)); |
||
| 70 | for (i = 1; i < MAX_PARTITION; i++) |
||
| 71 | mem_table[i].used = FALSE; |
||
| 72 | } else { |
||
| 73 | inited = 1; |
||
| 74 | } |
||
| 75 | } |
||
| 76 | |||
| 77 | LIN_ADDR DOS_alloc(DWORD s) |
||
| 78 | { |
||
| 79 | LIN_ADDR p = 0; |
||
| 80 | int i = 0; |
||
| 81 | |||
| 82 | while (i < MAX_PARTITION && p == NULL) { |
||
| 83 | if (mem_table[i].used && (mem_table[i].size >= s)) |
||
| 84 | p = mem_table[i].addr; |
||
| 85 | else |
||
| 86 | i++; |
||
| 87 | } |
||
| 88 | if (p != 0) { |
||
| 89 | if (mem_table[i].size > s) { |
||
| 90 | mem_table[i].size -= s; |
||
| 91 | mem_table[i].addr += s; |
||
| 92 | } else |
||
| 93 | mem_table[i].used = FALSE; |
||
| 94 | } |
||
| 95 | return (p); |
||
| 96 | } |
||
| 97 | |||
| 98 | int DOS_free(LIN_ADDR p, DWORD s) |
||
| 99 | { |
||
| 100 | register int i = 1; |
||
| 101 | unsigned i1 = 0, i2 = 0; |
||
| 102 | |||
| 103 | while (i < MAX_PARTITION && ((i1 == 0) || (i2 == 0))) { |
||
| 104 | if (mem_table[i].used) { |
||
| 105 | if (mem_table[i].addr + mem_table[i].size == p) |
||
| 106 | i1 = i; |
||
| 107 | if (mem_table[i].addr == p + s) |
||
| 108 | i2 = i; |
||
| 109 | } |
||
| 110 | i++; |
||
| 111 | } |
||
| 112 | if (i1 != 0 && i2 != 0) { |
||
| 113 | mem_table[i1].size += mem_table[i2].size + s; |
||
| 114 | mem_table[i2].used = FALSE; |
||
| 115 | } else if (i1 == 0 && i2 != 0) { |
||
| 116 | mem_table[i2].addr = p; |
||
| 117 | mem_table[i2].size += s; |
||
| 118 | } else if (i1 != 0 && i2 == 0) |
||
| 119 | mem_table[i1].size += s; |
||
| 120 | else { |
||
| 121 | i = 0; |
||
| 122 | while (i < MAX_PARTITION && (mem_table[i].used == TRUE)) |
||
| 123 | i++; |
||
| 124 | if (i == MAX_PARTITION) |
||
| 125 | return (FALSE); |
||
| 126 | mem_table[i].addr = p; |
||
| 127 | mem_table[i].size = s; |
||
| 128 | mem_table[i].used = TRUE; |
||
| 129 | } |
||
| 130 | return (TRUE); |
||
| 131 | } |