| [41] | 1 | ; File name : Line Splitter.asm
|
|---|
| 2 | ; Project name : Assembly Library
|
|---|
| 3 | ; Created date : 8.8.2010
|
|---|
| 4 | ; Last update : 15.9.2010
|
|---|
| 5 | ; Author : Tomi Tilli
|
|---|
| 6 | ; Description : Splits long strings to multiple lines.
|
|---|
| 7 |
|
|---|
| 8 | struc LINE_SPLITTER
|
|---|
| 9 | .pLastWord resb 2
|
|---|
| 10 | .wMaxLineLength resb 2
|
|---|
| 11 | .wLines resb 2
|
|---|
| 12 | endstruc
|
|---|
| 13 |
|
|---|
| 14 |
|
|---|
| 15 | ; Section containing code
|
|---|
| 16 | SECTION .text
|
|---|
| 17 |
|
|---|
| 18 | ;--------------------------------------------------------------------
|
|---|
| 19 | ; LineSplitter_SplitStringFromDSSIwithMaxLineLengthInAXandGetLineCountToAX
|
|---|
| 20 | ; Parameters:
|
|---|
| 21 | ; AX: Maximum allowed length for a line
|
|---|
| 22 | ; DS:SI: Ptr to string to split
|
|---|
| 23 | ; Returns:
|
|---|
| 24 | ; AX: Number of lines
|
|---|
| 25 | ; Corrupts registers:
|
|---|
| 26 | ; CX, SI
|
|---|
| 27 | ;--------------------------------------------------------------------
|
|---|
| 28 | ALIGN JUMP_ALIGN
|
|---|
| 29 | LineSplitter_SplitStringFromDSSIwithMaxLineLengthInAXandGetLineCountToAX:
|
|---|
| 30 | xor cx, cx
|
|---|
| 31 | cmp [si], cl ; String length zero?
|
|---|
| 32 | jne SHORT .PrepareToSplit
|
|---|
| 33 | xchg ax, cx
|
|---|
| 34 | ret
|
|---|
| 35 |
|
|---|
| 36 | ALIGN JUMP_ALIGN
|
|---|
| 37 | .PrepareToSplit:
|
|---|
| 38 | eENTER_STRUCT LINE_SPLITTER_size ; SS:BP now points to LINE_SPLITTER
|
|---|
| 39 |
|
|---|
| 40 | mov [bp+LINE_SPLITTER.wLines], cx
|
|---|
| 41 | call Memory_SetZFifNullPointerInDSSI
|
|---|
| 42 | jz SHORT .ReturnNumberOfLinesInAX
|
|---|
| 43 | call SplitStringFromDSSIusingLineSplitterInSSBP
|
|---|
| 44 |
|
|---|
| 45 | .ReturnNumberOfLinesInAX:
|
|---|
| 46 | mov ax, [bp+LINE_SPLITTER.wLines]
|
|---|
| 47 | eLEAVE_STRUCT LINE_SPLITTER_size
|
|---|
| 48 | ret
|
|---|
| 49 |
|
|---|
| 50 | ;--------------------------------------------------------------------
|
|---|
| 51 | ; SplitStringFromDSSIusingLineSplitterInSSBP
|
|---|
| 52 | ; Parameters:
|
|---|
| 53 | ; AX: Maximum allowed length for a line
|
|---|
| 54 | ; DS:SI: Ptr to string to split
|
|---|
| 55 | ; SS:BP: Ptr to LINE_SPLITTER
|
|---|
| 56 | ; Returns:
|
|---|
| 57 | ; SS:BP: Ptr to LINE_SPLITTER with number of lines
|
|---|
| 58 | ; Corrupts registers:
|
|---|
| 59 | ; AX, CX, SI
|
|---|
| 60 | ;--------------------------------------------------------------------
|
|---|
| 61 | ALIGN JUMP_ALIGN
|
|---|
| 62 | SplitStringFromDSSIusingLineSplitterInSSBP:
|
|---|
| 63 | mov [bp+LINE_SPLITTER.pLastWord], si
|
|---|
| 64 | mov [bp+LINE_SPLITTER.wMaxLineLength], ax
|
|---|
| 65 | inc WORD [bp+LINE_SPLITTER.wLines] ; Always at least one line
|
|---|
| 66 | xor cx, cx ; Length of current line
|
|---|
| 67 | cld
|
|---|
| 68 | ALIGN JUMP_ALIGN
|
|---|
| 69 | .ScanNextCharacter:
|
|---|
| 70 | lodsb ; Load from [DS:SI] to AL, increment SI
|
|---|
| 71 | cmp al, ' ' ; Control character or space?
|
|---|
| 72 | je SHORT .ProcessSpace
|
|---|
| 73 | jb SHORT .ProcessControlCharacter
|
|---|
| 74 | .IncrementCharacterCount:
|
|---|
| 75 | inc cx ; Increment character count
|
|---|
| 76 | cmp cx, [bp+LINE_SPLITTER.wMaxLineLength]
|
|---|
| 77 | jbe SHORT .ScanNextCharacter
|
|---|
| 78 |
|
|---|
| 79 | mov si, [bp+LINE_SPLITTER.pLastWord] ; Resume to beginning of last word
|
|---|
| 80 | mov BYTE [si-1], STX ; STX marks start or new line
|
|---|
| 81 | ; Fall to .StartNewLine
|
|---|
| 82 |
|
|---|
| 83 | ;--------------------------------------------------------------------
|
|---|
| 84 | ; .StartNewLine
|
|---|
| 85 | ; Parameters:
|
|---|
| 86 | ; CX: Line length so far
|
|---|
| 87 | ; DS:SI: Ptr character that begins new line
|
|---|
| 88 | ; SS:BP: Ptr to LINE_SPLITTER
|
|---|
| 89 | ; Returns:
|
|---|
| 90 | ; CX: Zero
|
|---|
| 91 | ; SS:BP: LINE_SPLITTER updated for number of lines
|
|---|
| 92 | ; Jumps to .ScanNextCharacter
|
|---|
| 93 | ; Corrupts registers:
|
|---|
| 94 | ; Nothing
|
|---|
| 95 | ;--------------------------------------------------------------------
|
|---|
| 96 | .StartNewLine:
|
|---|
| 97 | inc WORD [bp+LINE_SPLITTER.wLines] ; Increment number of lines
|
|---|
| 98 | xor cx, cx ; Zero line length
|
|---|
| 99 | jmp SHORT .ScanNextCharacter
|
|---|
| 100 |
|
|---|
| 101 | ;--------------------------------------------------------------------
|
|---|
| 102 | ; .ProcessSpace
|
|---|
| 103 | ; Parameters:
|
|---|
| 104 | ; CX: Line length so far
|
|---|
| 105 | ; DS:SI: Ptr first character after space
|
|---|
| 106 | ; SS:BP: Ptr to LINE_SPLITTER
|
|---|
| 107 | ; Returns:
|
|---|
| 108 | ; SS:BP: LINE_SPLITTER updated to beginning of next word
|
|---|
| 109 | ; Jumps to .IncrementCharacterCount
|
|---|
| 110 | ; Corrupts registers:
|
|---|
| 111 | ; Nothing
|
|---|
| 112 | ;--------------------------------------------------------------------
|
|---|
| 113 | ALIGN JUMP_ALIGN
|
|---|
| 114 | .ProcessSpace:
|
|---|
| 115 | mov [bp+LINE_SPLITTER.pLastWord], si
|
|---|
| 116 | jmp SHORT .IncrementCharacterCount
|
|---|
| 117 |
|
|---|
| 118 | ;--------------------------------------------------------------------
|
|---|
| 119 | ; .ProcessControlCharacter
|
|---|
| 120 | ; Parameters:
|
|---|
| 121 | ; AL: Control character
|
|---|
| 122 | ; CX: Line length so far
|
|---|
| 123 | ; DS:SI: Ptr inside string to split
|
|---|
| 124 | ; SS:BP: Ptr to LINE_SPLITTER
|
|---|
| 125 | ; Returns:
|
|---|
| 126 | ; SS:BP: LINE_SPLITTER updated to beginning of next line (LF control character)
|
|---|
| 127 | ; Corrupts registers:
|
|---|
| 128 | ; Nothing
|
|---|
| 129 | ;--------------------------------------------------------------------
|
|---|
| 130 | ALIGN JUMP_ALIGN
|
|---|
| 131 | .ProcessControlCharacter:
|
|---|
| 132 | cmp al, NULL ; End of string?
|
|---|
| 133 | je SHORT .EndOfString
|
|---|
| 134 | cmp al, LF ; Line feed?
|
|---|
| 135 | je SHORT .NewlineCharacter
|
|---|
| 136 | cmp al, SOH ; Previous newline character?
|
|---|
| 137 | je SHORT .NewlineCharacter
|
|---|
| 138 |
|
|---|
| 139 | mov BYTE [si-1], ' ' ; Replace unhandled control characters with space
|
|---|
| 140 | jmp SHORT .ProcessSpace
|
|---|
| 141 |
|
|---|
| 142 | ALIGN JUMP_ALIGN
|
|---|
| 143 | .NewlineCharacter:
|
|---|
| 144 | mov BYTE [si-1], SOH ; SOH marks previous newline character
|
|---|
| 145 | mov [bp+LINE_SPLITTER.pLastWord], si
|
|---|
| 146 | jmp SHORT .StartNewLine
|
|---|
| 147 |
|
|---|
| 148 | ALIGN JUMP_ALIGN
|
|---|
| 149 | .EndOfString:
|
|---|
| 150 | ret
|
|---|
| 151 |
|
|---|
| 152 |
|
|---|
| 153 | ;--------------------------------------------------------------------
|
|---|
| 154 | ; LineSplitter_PrintLineInCXfromStringInESDI
|
|---|
| 155 | ; Parameters:
|
|---|
| 156 | ; CX: Index of line to print
|
|---|
| 157 | ; ES:DI: Ptr to string containing the line
|
|---|
| 158 | ; Returns:
|
|---|
| 159 | ; Nothing
|
|---|
| 160 | ; Corrupts registers:
|
|---|
| 161 | ; AX, BX, SI
|
|---|
| 162 | ;--------------------------------------------------------------------
|
|---|
| 163 | ALIGN JUMP_ALIGN
|
|---|
| 164 | LineSplitter_PrintLineInCXfromStringInESDI:
|
|---|
| 165 | push di
|
|---|
| 166 | push cx
|
|---|
| 167 |
|
|---|
| 168 | call LineSplitter_GetOffsetToSIforLineCXfromStringInESDI
|
|---|
| 169 | jnc SHORT .LineNotFound
|
|---|
| 170 | mov bx, es
|
|---|
| 171 | CALL_DISPLAY_LIBRARY PrintCharBufferFromBXSIwithLengthInCX
|
|---|
| 172 | .LineNotFound:
|
|---|
| 173 | pop cx
|
|---|
| 174 | pop di
|
|---|
| 175 | ret
|
|---|
| 176 |
|
|---|
| 177 |
|
|---|
| 178 | ;--------------------------------------------------------------------
|
|---|
| 179 | ; LineSplitter_GetOffsetToSIforLineCXfromStringInESDI
|
|---|
| 180 | ; Parameters:
|
|---|
| 181 | ; CX: Index of line to search for
|
|---|
| 182 | ; ES:DI: Ptr to string
|
|---|
| 183 | ; Returns:
|
|---|
| 184 | ; CX: Line length
|
|---|
| 185 | ; ES:SI: Ptr to beginning of line
|
|---|
| 186 | ; CF: Set if wanted line was found
|
|---|
| 187 | ; Corrupts registers:
|
|---|
| 188 | ; AX, DI
|
|---|
| 189 | ;--------------------------------------------------------------------
|
|---|
| 190 | ALIGN JUMP_ALIGN
|
|---|
| 191 | LineSplitter_GetOffsetToSIforLineCXfromStringInESDI:
|
|---|
| 192 | mov si, di ; SI points to start of first line
|
|---|
| 193 | mov al, STX ; Last control character to scan for
|
|---|
| 194 | inc cx ; Increment CX to get length for first line
|
|---|
| 195 | cld
|
|---|
| 196 | ALIGN JUMP_ALIGN
|
|---|
| 197 | .LineScanLoop:
|
|---|
| 198 | scasb ; cmp al, [es:di]. Increment DI
|
|---|
| 199 | jb SHORT .LineScanLoop ; Non control character
|
|---|
| 200 |
|
|---|
| 201 | ; Our end of line characters or NULL character
|
|---|
| 202 | dec cx ; Decrement lines to scan through
|
|---|
| 203 | jz SHORT .WantedLineFound
|
|---|
| 204 | cmp BYTE [es:di-1], NULL
|
|---|
| 205 | je SHORT .EndOfString ; Jump with CF cleared
|
|---|
| 206 | mov si, di ; SI points to start of new line
|
|---|
| 207 | jmp SHORT .LineScanLoop
|
|---|
| 208 |
|
|---|
| 209 | ALIGN JUMP_ALIGN
|
|---|
| 210 | .WantedLineFound:
|
|---|
| 211 | stc ; Set CF since wanted line was found
|
|---|
| 212 | .EndOfString:
|
|---|
| 213 | lahf ; Load FLAGS low to AH
|
|---|
| 214 | lea cx, [di-1] ; We don't want control character to be printed
|
|---|
| 215 | sub cx, si ; String length to CX
|
|---|
| 216 | sahf ; Store AH to FLAGS low
|
|---|
| 217 | ret
|
|---|
