| 49ba9447 |
1 | ;------------------------------------------------------------------------------\r |
| 2 | ;\r |
| 3 | ; Copyright (c) 2008, Intel Corporation\r |
| 4 | ; All rights reserved. This program and the accompanying materials\r |
| 5 | ; are licensed and made available under the terms and conditions of the BSD License\r |
| 6 | ; which accompanies this distribution. The full text of the license may be found at\r |
| 7 | ; http://opensource.org/licenses/bsd-license.php\r |
| 8 | ;\r |
| 9 | ; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r |
| 10 | ; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r |
| 11 | ;\r |
| 12 | ; Module Name:\r |
| 13 | ;\r |
| 14 | ; 16RealTo32Flat.asm\r |
| 15 | ;\r |
| 16 | ; Abstract:\r |
| 17 | ;\r |
| 18 | ; Transition from 16 bit real mode into 32 bit flat protected mode\r |
| 19 | ;\r |
| 20 | ;------------------------------------------------------------------------------\r |
| 21 | \r |
| 22 | %define SEC_DEFAULT_CR0 0x40000023\r |
| 23 | %define SEC_DEFAULT_CR4 0x640\r |
| 24 | \r |
| 25 | BITS 16\r |
| 26 | \r |
| 27 | to32BitFlat:\r |
| 28 | \r |
| 29 | writeToSerialPort '1'\r |
| 30 | writeToSerialPort '6'\r |
| 31 | writeToSerialPort ' '\r |
| 32 | \r |
| 33 | cli\r |
| 34 | \r |
| 35 | mov bx, 0xf000\r |
| 36 | mov ds, bx\r |
| 37 | \r |
| 38 | mov bx, ADDR16_OF(gdtr)\r |
| 39 | \r |
| 40 | o32 lgdt [bx]\r |
| 41 | \r |
| 42 | mov eax, SEC_DEFAULT_CR0\r |
| 43 | mov cr0, eax\r |
| 44 | \r |
| 45 | ; mov eax, cr0\r |
| 46 | ; or al, 1\r |
| 47 | ; mov cr0, eax\r |
| 48 | \r |
| 49 | jmp LINEAR_CODE_SEL:dword ADDR_OF(jumpTo32BitAndLandHere)\r |
| 50 | BITS 32\r |
| 51 | jumpTo32BitAndLandHere:\r |
| 52 | \r |
| 53 | mov eax, SEC_DEFAULT_CR4\r |
| 54 | mov cr4, eax\r |
| 55 | \r |
| 56 | writeToSerialPort '3'\r |
| 57 | writeToSerialPort '2'\r |
| 58 | writeToSerialPort ' '\r |
| 59 | \r |
| 60 | mov ax, LINEAR_SEL\r |
| 61 | mov ds, ax\r |
| 62 | mov es, ax\r |
| 63 | mov fs, ax\r |
| 64 | mov gs, ax\r |
| 65 | mov ss, ax\r |
| 66 | \r |
| 67 | jmp TransitionFrom16RealTo32FlatComplete\r |
| 68 | \r |
| 69 | ALIGN 2\r |
| 70 | \r |
| 71 | gdtr:\r |
| 72 | dw GDT_END - GDT_BASE - 1 ; GDT limit\r |
| 73 | dd ADDR_OF(GDT_BASE)\r |
| 74 | \r |
| 75 | ALIGN 16\r |
| 76 | \r |
| 77 | GDT_BASE:\r |
| 78 | ; null descriptor\r |
| 79 | NULL_SEL equ $-GDT_BASE\r |
| 80 | dw 0 ; limit 15:0\r |
| 81 | dw 0 ; base 15:0\r |
| 82 | db 0 ; base 23:16\r |
| 83 | db 0 ; type\r |
| 84 | db 0 ; limit 19:16, flags\r |
| 85 | db 0 ; base 31:24\r |
| 86 | \r |
| 87 | ; linear data segment descriptor\r |
| 88 | LINEAR_SEL equ $-GDT_BASE\r |
| 89 | dw 0FFFFh ; limit 0xFFFFF\r |
| 90 | dw 0 ; base 0\r |
| 91 | db 0\r |
| 92 | db 092h ; present, ring 0, data, expand-up, writable\r |
| 93 | db 0CFh ; page-granular, 32-bit\r |
| 94 | db 0\r |
| 95 | \r |
| 96 | ; linear code segment descriptor\r |
| 97 | LINEAR_CODE_SEL equ $-GDT_BASE\r |
| 98 | dw 0FFFFh ; limit 0xFFFFF\r |
| 99 | dw 0 ; base 0\r |
| 100 | db 0\r |
| 101 | db 09Ah ; present, ring 0, data, expand-up, writable\r |
| 102 | db 0CFh ; page-granular, 32-bit\r |
| 103 | db 0\r |
| 104 | \r |
| 105 | ; system data segment descriptor\r |
| 106 | SYS_DATA_SEL equ $-GDT_BASE\r |
| 107 | dw 0FFFFh ; limit 0xFFFFF\r |
| 108 | dw 0 ; base 0\r |
| 109 | db 0\r |
| 110 | db 092h ; present, ring 0, data, expand-up, writable\r |
| 111 | db 0CFh ; page-granular, 32-bit\r |
| 112 | db 0\r |
| 113 | \r |
| 114 | ; system code segment descriptor\r |
| 115 | SYS_CODE_SEL equ $-GDT_BASE\r |
| 116 | dw 0FFFFh ; limit 0xFFFFF\r |
| 117 | dw 0 ; base 0\r |
| 118 | db 0\r |
| 119 | db 09Ah ; present, ring 0, data, expand-up, writable\r |
| 120 | db 0CFh ; page-granular, 32-bit\r |
| 121 | db 0\r |
| 122 | \r |
| 123 | ; spare segment descriptor\r |
| 124 | LINEAR_CODE64_SEL equ $-GDT_BASE\r |
| 125 | DW -1 ; LimitLow\r |
| 126 | DW 0 ; BaseLow\r |
| 127 | DB 0 ; BaseMid\r |
| 128 | DB 9bh\r |
| 129 | DB 0afh ; LimitHigh (CS.L=1, CS.D=0)\r |
| 130 | DB 0 ; BaseHigh\r |
| 131 | \r |
| 132 | ; spare segment descriptor\r |
| 133 | SPARE4_SEL equ $-GDT_BASE\r |
| 134 | dw 0 ; limit 0xFFFFF\r |
| 135 | dw 0 ; base 0\r |
| 136 | db 0\r |
| 137 | db 0 ; present, ring 0, data, expand-up, writable\r |
| 138 | db 0 ; page-granular, 32-bit\r |
| 139 | db 0\r |
| 140 | \r |
| 141 | ; spare segment descriptor\r |
| 142 | SPARE5_SEL equ $-GDT_BASE\r |
| 143 | dw 0 ; limit 0xFFFFF\r |
| 144 | dw 0 ; base 0\r |
| 145 | db 0\r |
| 146 | db 0 ; present, ring 0, data, expand-up, writable\r |
| 147 | db 0 ; page-granular, 32-bit\r |
| 148 | db 0\r |
| 149 | \r |
| 150 | GDT_END:\r |
| 151 | \r |
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