[54] | 1 | ; File name : Registers.asm |
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| 2 | ; Project name : Assembly Library |
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| 3 | ; Created date : 24.10.2010 |
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[66] | 4 | ; Last update : 6.12.2010 |
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[54] | 5 | ; Author : Tomi Tilli |
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| 6 | ; Description : Functions for register operations. |
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| 7 | |
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[66] | 8 | ;-------------------------------------------------------------------- |
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| 9 | ; NORMALIZE_FAR_POINTER |
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| 10 | ; Parameters: |
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| 11 | ; %1:%2: Far pointer to normalize |
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| 12 | ; %3: Scratch register |
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| 13 | ; %4: Scratch register |
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| 14 | ; Returns: |
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| 15 | ; %1:%2: Normalized far pointer |
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| 16 | ; Corrupts registers: |
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| 17 | ; %3, %4 |
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| 18 | ;-------------------------------------------------------------------- |
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| 19 | %macro NORMALIZE_FAR_POINTER 4 |
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| 20 | mov %4, %2 ; Copy offset to scratch reg |
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| 21 | and %2, BYTE 0Fh ; Clear offset bits 15...4 |
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| 22 | eSHR_IM %4, 4 ; Divide offset by 16 |
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| 23 | mov %3, %1 ; Copy segment to scratch reg |
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| 24 | add %3, %4 ; Add shifted offset to segment |
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| 25 | mov %1, %3 ; Set normalized segment |
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| 26 | %endmacro |
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| 27 | |
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| 28 | |
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[54] | 29 | ; Section containing code |
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| 30 | SECTION .text |
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| 31 | |
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| 32 | ;-------------------------------------------------------------------- |
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[66] | 33 | ; Registers_NormalizeDSSI |
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| 34 | ; Registers_NormalizeESDI |
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| 35 | ; Parameters |
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| 36 | ; DS:SI or ES:DI: Ptr to normalize |
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| 37 | ; Returns: |
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| 38 | ; DS:SI or ES:DI: Normalized pointer |
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| 39 | ; Corrupts registers: |
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| 40 | ; Nothing |
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| 41 | ;-------------------------------------------------------------------- |
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| 42 | ALIGN JUMP_ALIGN |
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| 43 | Registers_NormalizeDSSI: |
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| 44 | push dx |
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| 45 | push ax |
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| 46 | NORMALIZE_FAR_POINTER ds, si, ax, dx |
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| 47 | pop ax |
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| 48 | pop dx |
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| 49 | ret |
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| 50 | |
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| 51 | ALIGN JUMP_ALIGN |
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| 52 | Registers_NormalizeESDI: |
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| 53 | push dx |
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| 54 | push ax |
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| 55 | NORMALIZE_FAR_POINTER es, di, ax, dx |
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| 56 | pop ax |
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| 57 | pop dx |
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| 58 | ret |
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| 59 | |
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| 60 | |
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| 61 | ;-------------------------------------------------------------------- |
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[54] | 62 | ; Registers_ExchangeDSSIwithESDI |
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| 63 | ; Parameters |
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| 64 | ; Nothing |
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| 65 | ; Returns: |
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| 66 | ; DS:SI and ES:DI are exchanged. |
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| 67 | ; Corrupts registers: |
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| 68 | ; Nothing |
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| 69 | ;-------------------------------------------------------------------- |
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| 70 | ALIGN JUMP_ALIGN |
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| 71 | Registers_ExchangeDSSIwithESDI: |
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| 72 | push ds |
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| 73 | push es |
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| 74 | pop ds |
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| 75 | pop es |
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| 76 | xchg si, di |
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| 77 | ret |
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| 78 | |
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| 79 | |
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| 80 | ;-------------------------------------------------------------------- |
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| 81 | ; Registers_CopySSBPtoESDI |
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| 82 | ; Registers_CopySSBPtoDSSI |
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| 83 | ; Registers_CopyDSSItoESDI |
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| 84 | ; Registers_CopyESDItoDSSI |
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| 85 | ; Parameters |
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| 86 | ; Nothing |
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| 87 | ; Returns: |
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| 88 | ; Copies farm pointer to different segment/pointer register pair |
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| 89 | ; Corrupts registers: |
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| 90 | ; Nothing |
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| 91 | ;-------------------------------------------------------------------- |
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| 92 | ALIGN JUMP_ALIGN |
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| 93 | Registers_CopySSBPtoESDI: |
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| 94 | push ss |
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| 95 | pop es |
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| 96 | mov di, bp |
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| 97 | ret |
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| 98 | |
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| 99 | ALIGN JUMP_ALIGN |
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| 100 | Registers_CopySSBPtoDSSI: |
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| 101 | push ss |
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| 102 | pop ds |
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| 103 | mov si, bp |
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| 104 | ret |
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| 105 | |
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| 106 | ALIGN JUMP_ALIGN |
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| 107 | Registers_CopyDSSItoESDI: |
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| 108 | push ds |
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| 109 | pop es |
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| 110 | mov di, si |
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| 111 | ret |
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| 112 | |
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| 113 | ALIGN JUMP_ALIGN |
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| 114 | Registers_CopyESDItoDSSI: |
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| 115 | push es |
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| 116 | pop ds |
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| 117 | mov si, di |
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| 118 | ret |
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| 119 | |
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| 120 | |
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| 121 | ;-------------------------------------------------------------------- |
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| 122 | ; Registers_SetZFifNullPointerInDSSI |
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| 123 | ; Parameters |
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| 124 | ; DS:SI: Far pointer |
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| 125 | ; Returns: |
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| 126 | ; ZF: Set if NULL pointer in DS:SI |
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| 127 | ; Corrupts registers: |
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| 128 | ; Nothing |
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| 129 | ;-------------------------------------------------------------------- |
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| 130 | ALIGN JUMP_ALIGN |
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| 131 | Registers_SetZFifNullPointerInDSSI: |
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| 132 | push ax |
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| 133 | mov ax, ds |
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| 134 | or ax, si |
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| 135 | pop ax |
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| 136 | ret |
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