source: xtideuniversalbios/trunk/Assembly_Library/Src/Display/DisplayCharOut.asm@ 55

Last change on this file since 55 was 55, checked in by Tomi Tilli, 14 years ago

Changes to Assembly Library:

  • Character output to buffer now checks buffer length properly.
File size: 3.8 KB
Line 
1; File name : DisplayCharOut.asm
2; Project name : Assembly Library
3; Created date : 26.6.2010
4; Last update : 24.10.2010
5; Author : Tomi Tilli
6; Description : Functions for outputting characters to video memory.
7; These functions are meant to be called by Display_CharacterFromAL
8; and Display_RepeatCharacterFromAL using function pointer
9; stored in DISPLAY_CONTEXT.
10
11; Section containing code
12SECTION .text
13
14;--------------------------------------------------------------------
15; DisplayCharOut_TeletypeOutputWithAttribute
16; DisplayCharOut_TeletypeOutput
17; Parameters:
18; AL: Character to output
19; AH: Attribute to output
20; DS: BDA segment (zero)
21; ES:DI: Ptr to video memory where to output
22; Returns:
23; DI: Incremented for next character
24; Corrupts registers:
25; AX, DX
26;--------------------------------------------------------------------
27ALIGN JUMP_ALIGN
28DisplayCharOut_TeletypeOutputWithAttribute:
29 cmp al, ' ' ; Printable character?
30 jb SHORT DisplayCharOut_BiosTeletypeOutput
31 WAIT_RETRACE_IF_NECESSARY_THEN stosw
32 ret
33
34ALIGN JUMP_ALIGN
35DisplayCharOut_TeletypeOutput:
36 cmp al, ' ' ; Printable character?
37 jae SHORT DisplayCharOut_Character
38 ; Fall to DisplayCharOut_BiosTeletypeOutput
39
40;--------------------------------------------------------------------
41; DisplayCharOut_BiosTeletypeOutput
42; Parameters:
43; AL: Control character
44; DS: BDA segment (zero)
45; ES:DI: Ptr to video memory where to output
46; Returns:
47; DI: Incremented for next character
48; Corrupts registers:
49; AX, DX
50;--------------------------------------------------------------------
51ALIGN JUMP_ALIGN
52DisplayCharOut_BiosTeletypeOutput:
53 push ax
54 call DisplayCursor_SynchronizeCoordinatesToHardware
55 pop ax
56 call .OutputCharacterWithBIOS
57 call DisplayCursor_GetHardwareCoordinatesToAX
58 jmp DisplayCursor_SetCoordinatesFromAX
59
60;--------------------------------------------------------------------
61; .OutputCharacterWithBIOS
62; Parameters:
63; AL: Character to output
64; DS: BDA segment
65; Returns:
66; Nothing
67; Corrupts registers:
68; AX
69;--------------------------------------------------------------------
70ALIGN JUMP_ALIGN
71.OutputCharacterWithBIOS:
72 push bx
73 mov ah, TELETYPE_OUTPUT
74 mov bh, [VIDEO_BDA.bActivePage]
75 int BIOS_VIDEO_INTERRUPT_10h
76 pop bx
77 ret
78
79
80;--------------------------------------------------------------------
81; DisplayCharOut_Attribute
82; DisplayCharOut_Character
83; DisplayCharOut_CharacterWithAttribute
84; Parameters:
85; AL: Character to output
86; AH: Attribute to output
87; DS: BDA segment (zero)
88; ES:DI: Ptr to video memory where to output
89; Returns:
90; DI: Incremented for next character
91; Corrupts registers:
92; AX, DX
93;--------------------------------------------------------------------
94ALIGN JUMP_ALIGN
95DisplayCharOut_Attribute:
96 xchg al, ah ; Swap character and attribute
97 inc di ; Skip character
98 WAIT_RETRACE_IF_NECESSARY_THEN stosb
99 ret
100
101ALIGN JUMP_ALIGN
102DisplayCharOut_Character:
103 WAIT_RETRACE_IF_NECESSARY_THEN stosb
104 inc di ; Skip attribute
105 ret
106
107ALIGN JUMP_ALIGN
108DisplayCharOut_CharacterWithAttribute:
109 WAIT_RETRACE_IF_NECESSARY_THEN stosw
110 ret
111
112
113;--------------------------------------------------------------------
114; DisplayCharOut_WriteCharacterToBuffer
115; Parameters:
116; AL: Character to output
117; DS: BDA segment (zero)
118; ES:DI: Ptr to destination string buffer
119; DISPLAY_CONTEXT.wCharOutParam: Characters left in buffer
120; Returns:
121; ES:DI: Updated for next character
122; Corrupts registers:
123; AX, DX
124;--------------------------------------------------------------------
125ALIGN JUMP_ALIGN
126DisplayCharOut_WriteCharacterToBuffer:
127 cmp WORD [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.wCharOutParam], BYTE 0
128 je SHORT .BufferFull
129 stosb
130 dec WORD [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.wCharOutParam]
131.BufferFull:
132 ret
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