| 1 | ; Project name : Assembly Library
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| 2 | ; Description : Functions for displaying formatted strings.
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| 3 |
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| 4 | ; Section containing code
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| 5 | SECTION .text
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| 6 |
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| 7 | ;--------------------------------------------------------------------
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| 8 | ; DisplayFormat_ParseCharacters
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| 9 | ; Parameters:
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| 10 | ; DS: BDA segment (zero)
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| 11 | ; SS:BP: Pointer to first format parameter (-=2 updates to next parameter)
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| 12 | ; CS:SI: Pointer to string to format
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| 13 | ; ES:DI: Ptr to cursor location in video RAM
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| 14 | ; Returns:
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| 15 | ; CS:SI: Ptr to end of format string (ptr to one past NULL)
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| 16 | ; DI: Updated offset to video RAM
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| 17 | ; Corrupts registers:
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| 18 | ; AX, BX, CX, DX, BP
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| 19 | ;--------------------------------------------------------------------
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| 20 | ALIGN JUMP_ALIGN
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| 21 | DisplayFormat_ParseCharacters:
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| 22 | call ReadCharacterAndTestForNull
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| 23 | jz SHORT ReturnFromFormat
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| 24 |
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| 25 | ePUSH_T cx, DisplayFormat_ParseCharacters ; Return address
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| 26 | xor cx, cx ; Initial placeholder size
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| 27 | cmp al, '%' ; Format specifier?
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| 28 | jne SHORT DisplayPrint_CharacterFromAL
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| 29 | ; Fall to ParseFormatSpecifier
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| 30 |
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| 31 | ;--------------------------------------------------------------------
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| 32 | ; ParseFormatSpecifier
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| 33 | ; Parameters:
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| 34 | ; CX: Placeholder size
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| 35 | ; DS: BDA segment (zero)
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| 36 | ; SS:BP: Pointer to first format parameter (-=2 for next parameter)
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| 37 | ; CS:SI: Pointer to string to format
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| 38 | ; ES:DI: Ptr to cursor location in video RAM
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| 39 | ; Returns:
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| 40 | ; SI: Updated to first unparsed character
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| 41 | ; DI: Updated offset to video RAM
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| 42 | ; BP: Updated to next format parameter
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| 43 | ; Corrupts registers:
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| 44 | ; AX, BX, CX, DX
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| 45 | ;--------------------------------------------------------------------
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| 46 | ParseFormatSpecifier:
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| 47 | call ReadCharacterAndTestForNull
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| 48 | call Char_IsDecimalDigitInAL
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| 49 | jc SHORT ParsePlaceholderSizeDigitFromALtoCX
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| 50 | call GetFormatSpecifierParserToAX
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| 51 | call ax ; Parser function
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| 52 | dec bp
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| 53 | dec bp ; SS:BP now points to next parameter
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| 54 | test cx, cx
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| 55 | jnz SHORT PrependOrAppendSpaces
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| 56 | ReturnFromFormat:
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| 57 | ret
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| 58 |
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| 59 | ;--------------------------------------------------------------------
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| 60 | ; ParsePlaceholderSizeDigitFromALtoCX
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| 61 | ; Parameters:
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| 62 | ; AL: Digit character from format string
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| 63 | ; CX: Current placeholder size
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| 64 | ; DS: BDA segment (zero)
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| 65 | ; Returns:
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| 66 | ; CX: Current placeholder size
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| 67 | ; Jumps back to ParseFormatSpecifier
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| 68 | ; Corrupts registers:
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| 69 | ; AX
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| 70 | ;--------------------------------------------------------------------
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| 71 | ALIGN JUMP_ALIGN
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| 72 | ParsePlaceholderSizeDigitFromALtoCX:
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| 73 | mov [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.fpCursorPosition], di
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| 74 | sub al, '0' ; Digit '0'...'9' to integer 0...9
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| 75 | mov ah, cl ; Previous number parameter to AH
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| 76 | aad ; AL += (AH * 10)
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| 77 | mov cl, al ; Updated number parameter now in CX
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| 78 | jmp SHORT ParseFormatSpecifier
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| 79 |
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| 80 |
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| 81 | ;--------------------------------------------------------------------
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| 82 | ; ReadCharacterAndTestForNull
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| 83 | ; Parameters:
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| 84 | ; CS:SI: Pointer next character from string
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| 85 | ; Returns:
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| 86 | ; AL: Character from string
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| 87 | ; SI: Incremented to next character
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| 88 | ; ZF: Set if NULL, cleared if valid character
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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 | ReadCharacterAndTestForNull:
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| 94 | eSEG cs
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| 95 | lodsb ; Load from CS:SI to AL
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| 96 | test al, al ; NULL to end string?
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| 97 | ret
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| 98 |
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| 99 |
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| 100 | ;--------------------------------------------------------------------
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| 101 | ; GetFormatSpecifierParserToAX
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| 102 | ; Parameters:
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| 103 | ; AL: Format specifier character
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| 104 | ; Returns:
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| 105 | ; AX: Offset to parser function
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| 106 | ; Corrupts registers:
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| 107 | ; AX, BX
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| 108 | ;--------------------------------------------------------------------
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| 109 | ALIGN JUMP_ALIGN
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| 110 | GetFormatSpecifierParserToAX:
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| 111 | mov bx, .rgcFormatCharToLookupIndex
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| 112 | ALIGN JUMP_ALIGN
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| 113 | .CheckForNextSpecifierParser:
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| 114 | cmp al, [cs:bx]
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| 115 | je SHORT .ConvertIndexToFunctionOffset
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| 116 | inc bx
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| 117 | cmp bx, .rgcFormatCharToLookupIndexEnd
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| 118 | jb SHORT .CheckForNextSpecifierParser
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| 119 | mov ax, c_FormatCharacter
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| 120 | ret
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| 121 | ALIGN JUMP_ALIGN
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| 122 | .ConvertIndexToFunctionOffset:
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| 123 | sub bx, .rgcFormatCharToLookupIndex
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| 124 | shl bx, 1 ; Shift for WORD lookup
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| 125 | mov ax, [cs:bx+.rgfnFormatSpecifierParser]
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| 126 | ret
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| 127 |
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| 128 | .rgcFormatCharToLookupIndex:
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| 129 | db "aAduxsSct-+%"
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| 130 | .rgcFormatCharToLookupIndexEnd:
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| 131 | ALIGN WORD_ALIGN
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| 132 | .rgfnFormatSpecifierParser:
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| 133 | dw a_FormatAttributeForNextCharacter
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| 134 | dw A_FormatAttributeForRemainingString
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| 135 | dw d_FormatSignedDecimalWord
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| 136 | dw u_FormatUnsignedDecimalWord
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| 137 | dw x_FormatHexadecimalWord
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| 138 | dw s_FormatStringFromSegmentCS
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| 139 | dw S_FormatStringFromFarPointer
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| 140 | dw c_FormatCharacter
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| 141 | dw t_FormatRepeatCharacter
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| 142 | dw PrepareToPrependParameterWithSpaces
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| 143 | dw PrepareToAppendSpacesAfterParameter
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| 144 | dw percent_FormatPercent
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| 145 |
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| 146 |
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| 147 | ;--------------------------------------------------------------------
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| 148 | ; PrependOrAppendSpaces
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| 149 | ; Parameters:
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| 150 | ; CX: Minimum length for format specifier in characters
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| 151 | ; DS: BDA segment (zero)
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| 152 | ; ES:DI: Ptr to cursor location in video RAM
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| 153 | ; Returns:
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| 154 | ; Nothing
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| 155 | ; Corrupts registers:
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| 156 | ; AX, BX, CX, DX
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| 157 | ;--------------------------------------------------------------------
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| 158 | ALIGN JUMP_ALIGN
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| 159 | PrependOrAppendSpaces:
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| 160 | mov ax, di
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| 161 | sub ax, [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.fpCursorPosition]
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| 162 | test cx, cx
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| 163 | js SHORT .PrependWithSpaces
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| 164 | ; Fall to .AppendSpaces
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| 165 |
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| 166 | ;--------------------------------------------------------------------
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| 167 | ; .AppendSpaces
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| 168 | ; Parameters:
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| 169 | ; AX: Number of format parameter BYTEs printed
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| 170 | ; CX: Minimum length for format specifier in characters
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| 171 | ; DS: BDA segment (zero)
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| 172 | ; ES:DI: Ptr to cursor location in video RAM
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| 173 | ; Returns:
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| 174 | ; Nothing
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| 175 | ; Corrupts registers:
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| 176 | ; AX, CX, DX
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| 177 | ;--------------------------------------------------------------------
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| 178 | .AppendSpaces:
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| 179 | call DisplayContext_GetCharacterOffsetToAXfromByteOffsetInAX
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| 180 | sub cx, ax
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| 181 | jle SHORT .NothingToAppendOrPrepend
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| 182 | mov al, ' '
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| 183 | jmp DisplayPrint_RepeatCharacterFromALwithCountInCX
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| 184 |
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| 185 | ;--------------------------------------------------------------------
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| 186 | ; .PrependWithSpaces
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| 187 | ; Parameters:
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| 188 | ; AX: Number of format parameter BYTEs printed
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| 189 | ; CX: Negative minimum length for format specifier in characters
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| 190 | ; DS: BDA segment (zero)
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| 191 | ; ES:DI: Ptr to cursor location in video RAM
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| 192 | ; Returns:
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| 193 | ; Nothing
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| 194 | ; Corrupts registers:
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| 195 | ; AX, BX, CX, DX
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| 196 | ;--------------------------------------------------------------------
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| 197 | ALIGN JUMP_ALIGN
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| 198 | .PrependWithSpaces:
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| 199 | xchg ax, cx
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| 200 | neg ax
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| 201 | call DisplayContext_GetByteOffsetToAXfromCharacterOffsetInAX
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| 202 | sub ax, cx ; AX = BYTEs to prepend, CX = BYTEs to move
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| 203 | jle SHORT .NothingToAppendOrPrepend
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| 204 |
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| 205 | std
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| 206 | push si
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| 207 |
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| 208 | lea si, [di-1] ; SI = Offset to last byte formatted
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| 209 | add di, ax ; DI = Cursor location after preceeding completed
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| 210 | push di
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| 211 | dec di ; DI = Offset where to move last byte formatted
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| 212 | xchg bx, ax ; BX = BYTEs to prepend
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| 213 | call .ReverseCopyCXbytesFromESSItoESDI
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| 214 | xchg ax, bx
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| 215 | call .ReversePrintAXspacesStartingFromESDI
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| 216 |
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| 217 | pop di
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| 218 | pop si
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| 219 | cld ; Restore DF
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| 220 | .NothingToAppendOrPrepend:
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| 221 | ret
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| 222 |
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| 223 | ;--------------------------------------------------------------------
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| 224 | ; .ReverseCopyCXbytesFromESSItoESDI
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| 225 | ; Parameters:
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| 226 | ; CX: Number of bytes to copy
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| 227 | ; DS: BDA segment (zero)
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| 228 | ; ES:SI: Ptr to old location
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| 229 | ; ES:DI: Ptr to new location
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| 230 | ; Returns:
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| 231 | ; DI: Updated to before last character copied
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| 232 | ; Corrupts registers:
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| 233 | ; AX, CX, DX, SI
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| 234 | ;--------------------------------------------------------------------
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| 235 | ALIGN JUMP_ALIGN
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| 236 | .ReverseCopyCXbytesFromESSItoESDI:
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| 237 | test BYTE [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.bFlags], FLG_CONTEXT_ATTRIBUTES
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| 238 | jz SHORT .CopyWithoutDisplayProcessing
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| 239 |
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| 240 | WAIT_RETRACE_IF_NECESSARY_THEN rep movsb
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| 241 | dec di ; Point to preceeding character instead of attribute
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| 242 | ret
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| 243 | ALIGN JUMP_ALIGN
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| 244 | .CopyWithoutDisplayProcessing:
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| 245 | eSEG_STR rep, es, movsb
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| 246 | ret
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| 247 |
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| 248 | ;--------------------------------------------------------------------
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| 249 | ; .ReversePrintAXspacesStartingFromESDI
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| 250 | ; Parameters:
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| 251 | ; AX: Number of spaces to print
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| 252 | ; DS: BDA segment (zero)
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| 253 | ; ES:DI: Ptr to destination in video RAM
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| 254 | ; Returns:
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| 255 | ; DI: Updated
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| 256 | ; Corrupts registers:
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| 257 | ; AX, CX, DX
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| 258 | ALIGN JUMP_ALIGN
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| 259 | .ReversePrintAXspacesStartingFromESDI:
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| 260 | call DisplayContext_GetCharacterOffsetToAXfromByteOffsetInAX
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| 261 | xchg cx, ax ; CX = Spaces to prepend
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| 262 | mov al, ' '
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| 263 | jmp DisplayPrint_RepeatCharacterFromALwithCountInCX
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| 264 |
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| 265 |
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| 266 |
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| 267 | ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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| 268 | ; Formatting functions
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| 269 | ; Parameters:
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| 270 | ; DS: BDA segment (zero)
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| 271 | ; SS:BP: Pointer to next format parameter (-=2 updates to next parameter)
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| 272 | ; ES:DI: Ptr to cursor location in video RAM
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| 273 | ; Returns:
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| 274 | ; SS:BP: Points to last WORD parameter used
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| 275 | ; Corrupts registers:
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| 276 | ; AX, BX, DX
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| 277 | ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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| 278 | ALIGN JUMP_ALIGN
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| 279 | a_FormatAttributeForNextCharacter:
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| 280 | mov bl, [bp]
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| 281 | xchg bl, [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.bAttribute]
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| 282 | push bx
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| 283 | push cx
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| 284 | push di
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| 285 | call DisplayFormat_ParseCharacters ; Recursive call
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| 286 | pop WORD [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.fpCursorPosition]
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| 287 | pop cx
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| 288 | pop bx
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| 289 | mov [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.bAttribute], bl
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| 290 | ret
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| 291 |
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| 292 | ALIGN JUMP_ALIGN
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| 293 | A_FormatAttributeForRemainingString:
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| 294 | mov al, [bp]
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| 295 | mov [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.bAttribute], al
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| 296 | ret
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| 297 |
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| 298 | ALIGN JUMP_ALIGN
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| 299 | d_FormatSignedDecimalWord:
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| 300 | mov ax, [bp]
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| 301 | mov bx, 10
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| 302 | jmp DisplayPrint_SignedWordFromAXWithBaseInBX
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| 303 |
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| 304 | ALIGN JUMP_ALIGN
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| 305 | u_FormatUnsignedDecimalWord:
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| 306 | mov ax, [bp]
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| 307 | mov bx, 10
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| 308 | jmp DisplayPrint_WordFromAXWithBaseInBX
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| 309 |
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| 310 | ALIGN JUMP_ALIGN
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| 311 | x_FormatHexadecimalWord:
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| 312 | mov ax, [bp]
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| 313 | mov bx, 16
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| 314 | call DisplayPrint_WordFromAXWithBaseInBX
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| 315 | mov al, 'h'
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| 316 | jmp DisplayPrint_CharacterFromAL
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| 317 |
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| 318 | ALIGN JUMP_ALIGN
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| 319 | s_FormatStringFromSegmentCS:
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| 320 | xchg si, [bp]
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| 321 | call DisplayPrint_NullTerminatedStringFromCSSI
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| 322 | mov si, [bp]
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| 323 | ret
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| 324 |
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| 325 | ALIGN JUMP_ALIGN
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| 326 | S_FormatStringFromFarPointer:
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| 327 | mov bx, [bp-2]
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| 328 | xchg si, [bp]
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| 329 | call DisplayPrint_NullTerminatedStringFromBXSI
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| 330 | mov si, [bp]
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| 331 | dec bp
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| 332 | dec bp
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| 333 | ret
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| 334 |
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| 335 | ALIGN JUMP_ALIGN
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| 336 | c_FormatCharacter:
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| 337 | mov al, [bp]
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| 338 | jmp DisplayPrint_CharacterFromAL
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| 339 |
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| 340 | ALIGN JUMP_ALIGN
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| 341 | t_FormatRepeatCharacter:
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| 342 | push cx
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| 343 | mov cx, [bp-2]
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| 344 | mov al, [bp]
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| 345 | call DisplayPrint_RepeatCharacterFromALwithCountInCX
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| 346 | pop cx
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| 347 | dec bp
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| 348 | dec bp
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| 349 | ret
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| 350 |
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| 351 | ALIGN JUMP_ALIGN
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| 352 | percent_FormatPercent:
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| 353 | mov al, '%'
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| 354 | jmp DisplayPrint_CharacterFromAL
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| 355 |
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| 356 | ALIGN JUMP_ALIGN
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| 357 | PrepareToPrependParameterWithSpaces:
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| 358 | neg cx
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| 359 | ; Fall to PrepareToAppendSpacesAfterParameter
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| 360 |
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| 361 | ALIGN JUMP_ALIGN
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| 362 | PrepareToAppendSpacesAfterParameter:
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| 363 | add sp, BYTE 2 ; Remove return offset
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| 364 | jmp ParseFormatSpecifier
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