| 1 | ; Project name : Assembly Library
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| 2 | ; Description : Functions for size calculations.
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| 3 |
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| 4 | struc BYTE_MULTIPLES
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| 5 | .B resb 1
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| 6 | .kiB resb 1
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| 7 | .MiB resb 1
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| 8 | .GiB resb 1
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| 9 | .TiB resb 1
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| 10 | endstruc
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| 11 |
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| 12 | ; Section containing code
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| 13 | SECTION .text
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| 14 |
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| 15 | ;--------------------------------------------------------------------
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| 16 | ; Size_GetSizeToAXAndCharToDLfromBXDXAXwithMagnitudeInCX
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| 17 | ; Parameters:
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| 18 | ; BX:DX:AX: Size in magnitude
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| 19 | ; CX: Magnitude in BYTE_MULTIPLES
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| 20 | ; Returns:
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| 21 | ; AX: Size in magnitude
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| 22 | ; CX: Tenths
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| 23 | ; DL: Magnitude character:
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| 24 | ; 'k' = *1024 B = kiB
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| 25 | ; 'M' = *1024 kiB = MiB
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| 26 | ; 'G' = *1024 MiB = GiB
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| 27 | ; 'T' = *1024 GiB = TiB
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| 28 | ; 'P' = *1024 TiB = PiB
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| 29 | ; Corrupts registers:
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| 30 | ; BX, DH
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| 31 | ;--------------------------------------------------------------------
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| 32 | ALIGN JUMP_ALIGN
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| 33 | Size_GetSizeToAXAndCharToDLfromBXDXAXwithMagnitudeInCX:
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| 34 | push si
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| 35 |
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| 36 | ALIGN JUMP_ALIGN
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| 37 | .MagnitudeConversionLoop:
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| 38 | ePUSH_T si, .MagnitudeConversionLoop
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| 39 | test bx, bx ; Bits 32...47 in use?
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| 40 | jnz SHORT Size_DivideSizeInBXDXAXby1024andIncrementMagnitudeInCX
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| 41 | test dx, dx ; Bits 16...31 in use?
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| 42 | jnz SHORT Size_DivideSizeInBXDXAXby1024andIncrementMagnitudeInCX
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| 43 | cmp ax, 10000 ; 5 digits needed?
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| 44 | jae SHORT Size_DivideSizeInBXDXAXby1024andIncrementMagnitudeInCX
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| 45 |
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| 46 | add sp, BYTE 2 ; Clean return address from stack
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| 47 | call Size_ConvertMagnitudeRemainderInSItoTenths
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| 48 | call Size_GetMagnitudeCharacterToDLfromMagnitudeInCX
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| 49 | mov cx, si
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| 50 |
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| 51 | pop si
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| 52 | ret
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| 53 |
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| 54 | ;--------------------------------------------------------------------
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| 55 | ; Size_DivideSizeInBXDXAXby1024andIncrementMagnitudeInCX
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| 56 | ; Parameters:
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| 57 | ; BX:DX:AX: Size
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| 58 | ; CX: Magnitude in BYTE_MULTIPLES
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| 59 | ; Returns:
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| 60 | ; BX:DX:AX: Size in magnitude
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| 61 | ; SI: Remainder (0...1023)
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| 62 | ; CX: Magnitude in BYTE_MULTIPLES
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| 63 | ; Corrupts registers:
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| 64 | ; Nothing
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| 65 | ;--------------------------------------------------------------------
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| 66 | ALIGN JUMP_ALIGN
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| 67 | Size_DivideSizeInBXDXAXby1024andIncrementMagnitudeInCX:
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| 68 | push cx
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| 69 | xor si, si ; Zero remainder
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| 70 | mov cl, 10 ; Divide by 1024
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| 71 | ALIGN JUMP_ALIGN
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| 72 | .ShiftLoop:
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| 73 | call Size_DivideBXDXAXbyTwo
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| 74 | rcr si, 1 ; Update remainder
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| 75 | loop .ShiftLoop
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| 76 | eSHR_IM si, 6 ; Remainder to SI beginning
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| 77 | pop cx
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| 78 | inc cx ; Increment magnitude
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| 79 | ret
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| 80 |
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| 81 |
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| 82 | ;--------------------------------------------------------------------
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| 83 | ; Size_ConvertSectorCountInBXDXAXtoKiB
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| 84 | ; Size_DivideBXDXAXbyTwo
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| 85 | ; Parameters:
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| 86 | ; BX:DX:AX: Total sector count
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| 87 | ; Returns:
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| 88 | ; BX:DX:AX: Total size in kiB
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| 89 | ; CF: Remainder from division
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| 90 | ; Corrupts registers:
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| 91 | ; Nothing
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| 92 | ;--------------------------------------------------------------------
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| 93 | ALIGN JUMP_ALIGN
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| 94 | Size_ConvertSectorCountInBXDXAXtoKiB:
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| 95 | Size_DivideBXDXAXbyTwo:
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| 96 | shr bx, 1 ; Divide sector count by 2...
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| 97 | rcr dx, 1 ; ...to get disk size in...
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| 98 | rcr ax, 1 ; ...kiB
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| 99 | ret
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| 100 |
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| 101 |
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| 102 | ;--------------------------------------------------------------------
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| 103 | ; Size_ConvertMagnitudeRemainderInSItoTenths
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| 104 | ; Parameters:
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| 105 | ; SI: Remainder from last magnitude division (0...1023)
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| 106 | ; Returns:
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| 107 | ; SI: Tenths
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| 108 | ; Corrupts registers:
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| 109 | ; DX
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| 110 | ;--------------------------------------------------------------------
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| 111 | ALIGN JUMP_ALIGN
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| 112 | Size_ConvertMagnitudeRemainderInSItoTenths:
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| 113 | push ax
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| 114 |
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| 115 | mov ax, 10
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| 116 | mul si ; DX:AX = remainder * 10
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| 117 | eSHR_IM ax, 10 ; Divide AX by 1024
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| 118 | xchg si, ax ; SI = tenths
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| 119 |
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| 120 | pop ax
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| 121 | ret
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| 122 |
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| 123 |
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| 124 | ;--------------------------------------------------------------------
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| 125 | ; Size_GetMagnitudeCharacterToDLfromMagnitudeInCX
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| 126 | ; Parameters:
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| 127 | ; CX: Magnitude in BYTE_MULTIPLES
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| 128 | ; Returns:
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| 129 | ; DL: Magnitude character
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| 130 | ; Corrupts registers:
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| 131 | ; BX
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| 132 | ;--------------------------------------------------------------------
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| 133 | ALIGN JUMP_ALIGN
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| 134 | Size_GetMagnitudeCharacterToDLfromMagnitudeInCX:
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| 135 | mov bx, cx
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| 136 | mov dl, [cs:bx+.rgbMagnitudeToChar]
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| 137 | ret
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| 138 | ALIGN WORD_ALIGN
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| 139 | .rgbMagnitudeToChar: db " kMGTP"
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