source: xtideuniversalbios/trunk/Assembly_Library/Src/Display/DisplayFormat.asm@ 44

Last change on this file since 44 was 44, checked in by Tomi Tilli, 14 years ago

Spaces can now be generated before format specifier when printing formatted string.
Background character and attribute can now be easily specified before compiling.
File size: 9.4 KB
Line 
1; File name : DisplayFormat.asm
2; Project name : Assembly Library
3; Created date : 29.6.2010
4; Last update : 26.9.2010
5; Author : Tomi Tilli
6; Description : Functions for displaying formatted strings.
7
8; Section containing code
9SECTION .text
10
11;--------------------------------------------------------------------
12; DisplayFormat_ParseCharacters
13; Parameters:
14; DS: BDA segment (zero)
15; SS:BP: Pointer to first format parameter (-=2 updates to next parameter)
16; CS:SI: Pointer to string to format
17; ES:DI: Ptr to cursor location in video RAM
18; Returns:
19; CS:SI: Ptr to end of format string (ptr to one past NULL)
20; DI: Updated offset to video RAM
21; Corrupts registers:
22; AX, BX, CX, DX, BP
23;--------------------------------------------------------------------
24ALIGN JUMP_ALIGN
25DisplayFormat_ParseCharacters:
26 call ReadCharacterAndTestForNull
27 jz SHORT .QuitCharacterParsing
28
29 ePUSH_T cx, DisplayFormat_ParseCharacters ; Return address
30 xor cx, cx ; Initial placeholder size
31 cmp al, '%' ; Format specifier?
32 je SHORT ParseFormatSpecifier
33 jmp DisplayPrint_CharacterFromAL
34
35ALIGN JUMP_ALIGN
36.QuitCharacterParsing:
37 ret
38
39
40;--------------------------------------------------------------------
41; ParseFormatSpecifier
42; Parameters:
43; CX: Placeholder size
44; DS: BDA segment (zero)
45; SS:BP: Pointer to first format parameter (-=2 for next parameter)
46; CS:SI: Pointer to string to format
47; ES:DI: Ptr to cursor location in video RAM
48; Returns:
49; SI: Updated to first unparsed character
50; DI: Updated offset to video RAM
51; BP: Updated to next format parameter
52; Corrupts registers:
53; AX, BX, CX, DX
54;--------------------------------------------------------------------
55ALIGN JUMP_ALIGN
56ParseFormatSpecifier:
57 call ReadCharacterAndTestForNull
58 call Char_IsDecimalDigitInAL
59 jc SHORT .ParsePlaceholderSizeDigitFromALtoCX
60 call GetFormatSpecifierParserToAX
61 call ax ; Parser function
62 dec bp
63 dec bp ; SS:BP now points to next parameter
64 test cx, cx
65 jnz SHORT PrependOrAppendSpaces
66 ret
67
68;--------------------------------------------------------------------
69; .ParsePlaceholderSizeDigitFromALtoCX
70; Parameters:
71; AL: Digit character from format string
72; CX: Current placeholder size
73; DS: BDA segment (zero)
74; Returns:
75; CX: Current placeholder size
76; Jumps back to ParseFormatSpecifier
77; Corrupts registers:
78; AX
79;--------------------------------------------------------------------
80ALIGN JUMP_ALIGN
81.ParsePlaceholderSizeDigitFromALtoCX:
82 mov [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.fpCursorPosition], di
83 sub al, '0' ; Digit '0'...'9' to integer 0...9
84 mov ah, cl ; Previous number parameter to AH
85 aad ; AL += (AH * 10)
86 mov cl, al ; Updated number parameter now in CX
87 jmp SHORT ParseFormatSpecifier
88
89
90;--------------------------------------------------------------------
91; ReadCharacterAndTestForNull
92; Parameters:
93; CS:SI: Pointer next character from string
94; Returns:
95; AL: Character from string
96; SI: Incremented to next character
97; ZF: Set if NULL, cleared if valid character
98; Corrupts registers:
99; Nothing
100;--------------------------------------------------------------------
101ALIGN JUMP_ALIGN
102ReadCharacterAndTestForNull:
103 eSEG cs
104 lodsb ; Load from CS:SI to AL
105 test al, al ; NULL to end string?
106 ret
107
108
109;--------------------------------------------------------------------
110; GetFormatSpecifierParserToAX
111; Parameters:
112; AL: Format specifier character
113; Returns:
114; AX: Offset to parser function
115; Corrupts registers:
116; AX, BX
117;--------------------------------------------------------------------
118ALIGN JUMP_ALIGN
119GetFormatSpecifierParserToAX:
120 mov bx, .rgcFormatCharToLookupIndex
121ALIGN JUMP_ALIGN
122.CheckForNextSpecifierParser:
123 cmp al, [cs:bx]
124 je SHORT .ConvertIndexToFunctionOffset
125 inc bx
126 cmp bx, .rgcFormatCharToLookupIndexEnd
127 jb SHORT .CheckForNextSpecifierParser
128 mov ax, c_FormatCharacter
129 ret
130ALIGN JUMP_ALIGN
131.ConvertIndexToFunctionOffset:
132 sub bx, .rgcFormatCharToLookupIndex
133 shl bx, 1 ; Shift for WORD lookup
134 mov ax, [cs:bx+.rgfnFormatSpecifierParser]
135 ret
136
137.rgcFormatCharToLookupIndex:
138 db "aAduxsSct-+%"
139.rgcFormatCharToLookupIndexEnd:
140ALIGN WORD_ALIGN
141.rgfnFormatSpecifierParser:
142 dw a_FormatAttributeForNextCharacter
143 dw A_FormatAttributeForRemainingString
144 dw d_FormatSignedDecimalWord
145 dw u_FormatUnsignedDecimalWord
146 dw x_FormatHexadecimalWord
147 dw s_FormatStringFromSegmentCS
148 dw S_FormatStringFromFarPointer
149 dw c_FormatCharacter
150 dw t_FormatRepeatCharacter
151 dw PrepareToPrependParameterWithSpaces
152 dw PrepareToAppendSpacesAfterParameter
153 dw percent_FormatPercent
154
155
156;--------------------------------------------------------------------
157; PrependOrAppendSpaces
158; Parameters:
159; CX: Minimum length for format specifier in characters
160; DS: BDA segment (zero)
161; ES:DI: Ptr to cursor location in video RAM
162; Returns:
163; Nothing
164; Corrupts registers:
165; AX, BX, CX, DX
166;--------------------------------------------------------------------
167ALIGN JUMP_ALIGN
168PrependOrAppendSpaces:
169 mov ax, di
170 sub ax, [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.fpCursorPosition]
171 test cx, cx
172 js SHORT .PrependWithSpaces
173 ; Fall to .AppendSpaces
174
175;--------------------------------------------------------------------
176; .AppendSpaces
177; Parameters:
178; AX: Number of format parameter BYTEs printed
179; CX: Minimum length for format specifier in characters
180; DS: BDA segment (zero)
181; ES:DI: Ptr to cursor location in video RAM
182; Returns:
183; Nothing
184; Corrupts registers:
185; AX, CX, DX
186;--------------------------------------------------------------------
187.AppendSpaces:
188 call DisplayContext_GetCharacterOffsetToAXfromByteOffsetInAX
189 sub cx, ax
190 jle SHORT .NothingToAppendOrPrepend
191 mov al, ' '
192 jmp DisplayPrint_RepeatCharacterFromALwithCountInCX
193
194;--------------------------------------------------------------------
195; .PrependWithSpaces
196; Parameters:
197; AX: Number of format parameter BYTEs printed
198; CX: Negative minimum length for format specifier in characters
199; DS: BDA segment (zero)
200; ES:DI: Ptr to cursor location in video RAM
201; Returns:
202; Nothing
203; Corrupts registers:
204; AX, BX, CX, DX
205;--------------------------------------------------------------------
206ALIGN JUMP_ALIGN
207.PrependWithSpaces:
208 xchg ax, cx
209 neg ax
210 call DisplayContext_GetByteOffsetToAXfromCharacterOffsetInAX
211 sub ax, cx ; AX = BYTEs to prepend, CX = BYTEs to move
212 jle SHORT .NothingToAppendOrPrepend
213
214 mov bx, di
215 add bx, ax ; BX = DI after prepending
216
217 push si
218 dec di ; DI = Offset to last byte formatted
219 mov si, di
220 add di, ax ; DI = Offset to new location for last byte
221 std
222 eSEG_STR rep, es, movsb
223
224 mov dl, [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.bFlags]
225 and dx, BYTE FLG_CONTEXT_ATTRIBUTES
226 not dx
227 and di, dx ; WORD alignment when using attributes
228
229 call DisplayContext_GetCharacterOffsetToAXfromByteOffsetInAX
230 xchg cx, ax ; CX = Spaces to prepend
231 mov al, ' '
232 call DisplayPrint_RepeatCharacterFromALwithCountInCX
233 cld ; Restore DF
234
235 mov di, bx
236 pop si
237.NothingToAppendOrPrepend:
238 ret
239
240
241;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
242; Formatting functions
243; Parameters:
244; DS: BDA segment (zero)
245; SS:BP: Pointer to next format parameter (-=2 updates to next parameter)
246; ES:DI: Ptr to cursor location in video RAM
247; Returns:
248; SS:BP: Points to last WORD parameter used
249; Corrupts registers:
250; AX, BX, DX
251;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
252ALIGN JUMP_ALIGN
253a_FormatAttributeForNextCharacter:
254 mov bl, [bp]
255 xchg bl, [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.bAttribute]
256 push bx
257 push cx
258 push di
259 call DisplayFormat_ParseCharacters ; Recursive call
260 pop WORD [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.fpCursorPosition]
261 pop cx
262 pop bx
263 mov [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.bAttribute], bl
264 ret
265
266ALIGN JUMP_ALIGN
267A_FormatAttributeForRemainingString:
268 mov al, [bp]
269 mov [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.bAttribute], al
270 ret
271
272ALIGN JUMP_ALIGN
273d_FormatSignedDecimalWord:
274 mov ax, [bp]
275 mov bx, 10
276 jmp DisplayPrint_SignedWordFromAXWithBaseInBX
277
278ALIGN JUMP_ALIGN
279u_FormatUnsignedDecimalWord:
280 mov ax, [bp]
281 mov bx, 10
282 jmp DisplayPrint_WordFromAXWithBaseInBX
283
284ALIGN JUMP_ALIGN
285x_FormatHexadecimalWord:
286 mov ax, [bp]
287 mov bx, 16
288 call DisplayPrint_WordFromAXWithBaseInBX
289 mov al, 'h'
290 jmp DisplayPrint_CharacterFromAL
291
292ALIGN JUMP_ALIGN
293s_FormatStringFromSegmentCS:
294 xchg si, [bp]
295 call DisplayPrint_NullTerminatedStringFromCSSI
296 mov si, [bp]
297 ret
298
299ALIGN JUMP_ALIGN
300S_FormatStringFromFarPointer:
301 mov bx, [bp-2]
302 xchg si, [bp]
303 call DisplayPrint_NullTerminatedStringFromBXSI
304 mov si, [bp]
305 dec bp
306 dec bp
307 ret
308
309ALIGN JUMP_ALIGN
310c_FormatCharacter:
311 mov al, [bp]
312 jmp DisplayPrint_CharacterFromAL
313
314ALIGN JUMP_ALIGN
315t_FormatRepeatCharacter:
316 push cx
317 mov cx, [bp-2]
318 mov al, [bp]
319 call DisplayPrint_RepeatCharacterFromALwithCountInCX
320 pop cx
321 dec bp
322 dec bp
323 ret
324
325ALIGN JUMP_ALIGN
326percent_FormatPercent:
327 mov al, '%'
328 jmp DisplayPrint_CharacterFromAL
329
330ALIGN JUMP_ALIGN
331PrepareToPrependParameterWithSpaces:
332 neg cx
333 ; Fall to PrepareToAppendSpacesAfterParameter
334
335ALIGN JUMP_ALIGN
336PrepareToAppendSpacesAfterParameter:
337 add sp, BYTE 2 ; Remove return offset
338 jmp ParseFormatSpecifier
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