1 | ; File name : Size.asm |
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2 | ; Project name : Assembly Library |
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3 | ; Created date : 7.9.2010 |
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4 | ; Last update : 15.9.2010 |
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5 | ; Author : Tomi Tilli |
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6 | ; Description : Functions for size calculations. |
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7 | |
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8 | ; Section containing code |
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9 | SECTION .text |
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10 | |
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11 | ;-------------------------------------------------------------------- |
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12 | ; Size_GetWordSizeToAXfromBXDXAXwithMagnitudeInCX |
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13 | ; Parameters: |
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14 | ; BX:DX:AX: Size in magnitude |
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15 | ; CX: Magnitude (0=B, 1=kiB, 2=MiB...) |
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16 | ; Returns: |
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17 | ; AX: Size in magnitude |
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18 | ; CX: Tenths |
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19 | ; DL: Magnitude character: |
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20 | ; 'k' = *1024 B = kiB |
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21 | ; 'M' = *1024 kiB = MiB |
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22 | ; 'G' = *1024 MiB = GiB |
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23 | ; 'T' = *1024 GiB = TiB |
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24 | ; 'P' = *1024 TiB = PiB |
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25 | ; Corrupts registers: |
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26 | ; BX, DH |
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27 | ;-------------------------------------------------------------------- |
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28 | ALIGN JUMP_ALIGN |
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29 | Size_GetSizeToAXAndCharToDLfromBXDXAXwithMagnitudeInCX: |
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30 | push si |
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31 | |
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32 | ALIGN JUMP_ALIGN |
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33 | .MagnitudeConversionLoop: |
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34 | ePUSH_T si, .MagnitudeConversionLoop |
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35 | test bx, bx ; Bits 32...47 in use? |
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36 | jnz SHORT Size_DivideSizeInBXDXAXby1024andIncrementMagnitudeInCX |
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37 | test dx, dx ; Bits 16...31 in use? |
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38 | jnz SHORT Size_DivideSizeInBXDXAXby1024andIncrementMagnitudeInCX |
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39 | cmp ax, 10000 ; 5 digits needed? |
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40 | jae SHORT Size_DivideSizeInBXDXAXby1024andIncrementMagnitudeInCX |
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41 | |
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42 | add sp, BYTE 2 ; Clean return address from stack |
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43 | call Size_ConvertMagnitudeRemainderInSItoTenths |
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44 | call Size_GetMagnitudeCharacterToDLfromMagnitudeInCX |
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45 | mov cx, si |
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46 | |
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47 | pop si |
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48 | ret |
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49 | |
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50 | ;-------------------------------------------------------------------- |
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51 | ; Size_DivideSizeInBXDXAXby1024andIncrementMagnitudeInCX |
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52 | ; Parameters: |
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53 | ; BX:DX:AX: Size |
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54 | ; CX: Magnitude (0=B, 1=kiB, 2=MiB...) |
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55 | ; Returns: |
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56 | ; BX:DX:AX: Size in magnitude |
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57 | ; SI: Remainder (0...1023) |
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58 | ; CX: Magnitude (1=kiB, 2=MiB...) |
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59 | ; Corrupts registers: |
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60 | ; Nothing |
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61 | ;-------------------------------------------------------------------- |
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62 | ALIGN JUMP_ALIGN |
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63 | Size_DivideSizeInBXDXAXby1024andIncrementMagnitudeInCX: |
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64 | push cx |
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65 | xor si, si ; Zero remainder |
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66 | mov cl, 10 ; Divide by 1024 |
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67 | ALIGN JUMP_ALIGN |
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68 | .ShiftLoop: |
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69 | call Size_DivideBXDXAXbyTwo |
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70 | rcr si, 1 ; Update remainder |
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71 | loop .ShiftLoop |
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72 | eSHR_IM si, 6 ; Remainder to SI beginning |
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73 | pop cx |
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74 | inc cx ; Increment magnitude |
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75 | ret |
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76 | |
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77 | |
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78 | ;-------------------------------------------------------------------- |
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79 | ; Size_ConvertSectorCountInBXDXAXtoKiB |
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80 | ; Size_DivideBXDXAXbyTwo |
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81 | ; Parameters: |
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82 | ; BX:DX:AX: Total sector count |
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83 | ; Returns: |
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84 | ; BX:DX:AX: Total size in kiB |
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85 | ; CF: Remainder from division |
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86 | ; Corrupts registers: |
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87 | ; Nothing |
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88 | ;-------------------------------------------------------------------- |
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89 | ALIGN JUMP_ALIGN |
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90 | Size_ConvertSectorCountInBXDXAXtoKiB: |
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91 | Size_DivideBXDXAXbyTwo: |
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92 | shr bx, 1 ; Divide sector count by 2... |
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93 | rcr dx, 1 ; ...to get disk size in... |
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94 | rcr ax, 1 ; ...kiB |
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95 | ret |
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96 | |
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97 | |
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98 | ;-------------------------------------------------------------------- |
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99 | ; Size_ConvertMagnitudeRemainderInSItoTenths |
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100 | ; Parameters: |
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101 | ; SI: Remainder from last magnitude division (0...1023) |
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102 | ; Returns: |
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103 | ; SI: Tenths |
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104 | ; Corrupts registers: |
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105 | ; DX |
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106 | ;-------------------------------------------------------------------- |
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107 | ALIGN JUMP_ALIGN |
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108 | Size_ConvertMagnitudeRemainderInSItoTenths: |
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109 | push ax |
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110 | |
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111 | mov ax, 10 |
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112 | mul si ; DX:AX = remainder * 10 |
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113 | eSHR_IM ax, 10 ; Divide AX by 1024 |
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114 | xchg si, ax ; SI = tenths |
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115 | |
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116 | pop ax |
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117 | ret |
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118 | |
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119 | |
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120 | ;-------------------------------------------------------------------- |
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121 | ; Size_GetMagnitudeCharacterToDLfromMagnitudeInCX |
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122 | ; Parameters: |
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123 | ; CX: Magnitude (0=B, 1=kiB, 2=MiB...) |
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124 | ; Returns: |
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125 | ; DL: Magnitude character |
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126 | ; Corrupts registers: |
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127 | ; BX |
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128 | ;-------------------------------------------------------------------- |
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129 | ALIGN JUMP_ALIGN |
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130 | Size_GetMagnitudeCharacterToDLfromMagnitudeInCX: |
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131 | mov bx, cx |
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132 | mov dl, [cs:bx+.rgbMagnitudeToChar] |
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133 | ret |
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134 | ALIGN WORD_ALIGN |
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135 | .rgbMagnitudeToChar: db " kMGTP" |
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