source: xtideuniversalbios/trunk/Assembly_Library/Src/String/StringProcess.asm@ 57

Last change on this file since 57 was 52, checked in by Tomi Tilli, 14 years ago

Changes to Assembly Library:
Completely rewritten line splitting (slower but no need to modify string).
Some changes to string processing functions.
Saved few bytes from CGA detection.
File size: 3.0 KB
Line 
1; File name : StringProcess.asm
2; Project name : Assembly Library
3; Created date : 12.10.2010
4; Last update : 12.10.2010
5; Author : Tomi Tilli
6; Description : Functions for processing characters in a string.
7
8; Section containing code
9SECTION .text
10
11;--------------------------------------------------------------------
12; Character processing callback function prototype for StringProcess_DSSIwithFunctionInBX.
13; Parameters:
14; AL: Character to process
15; CX: Number of characters processed
16; DS:SI: Ptr to next character
17; BX,DI,ES: Free to use by processing function
18; Returns:
19; CF: Clear to continue with next character
20; Set to stop processing
21; BX,DI,ES: Free to use by processing function
22; Corrupts registers:
23; AX
24;--------------------------------------------------------------------
25
26
27;--------------------------------------------------------------------
28; StringProcess_DSSIwithFunctionInDX
29; Parameters:
30; DX: Character processing function
31; DS:SI: Ptr to NULL terminated string to convert
32; Returns:
33; CX: Number of characters processed
34; CF: Clear if all characters processed
35; Set if terminated by processing function
36; Corrupts registers:
37; Nothing (processing function can corrupt BX,DI,ES)
38;--------------------------------------------------------------------
39ALIGN JUMP_ALIGN
40StringProcess_DSSIwithFunctionInDX:
41 push si
42 push ax
43
44 xor cx, cx
45ALIGN JUMP_ALIGN
46.ProcessNextCharacter:
47 lodsb
48 test al, al ; NULL to end string
49 jz SHORT .EndOfString ; Return with CF cleared
50 inc cx
51 call dx
52 jnc SHORT .ProcessNextCharacter
53
54ALIGN JUMP_ALIGN
55.EndOfString:
56 pop ax
57 pop si
58 ret
59
60
61;--------------------------------------------------------------------
62; StringProcess_ConvertToLowerCase (callback function for StringProcess_DSSIwithFunctionInDX)
63; Parameters:
64; AL: Character to convert to lower case
65; DS:SI: Ptr to next character
66; Returns:
67; CF: Clear to continue processing
68; Corrupts registers:
69; AL
70;--------------------------------------------------------------------
71ALIGN JUMP_ALIGN
72StringProcess_ConvertToLowerCase:
73 call Char_ALtoLowerCaseLetter
74 mov [si-1], al
75 clc
76 ret
77
78
79;--------------------------------------------------------------------
80; StringProcess_ConvertToWordInDIWithBaseInBX (callback function for StringProcess_DSSIwithFunctionInDX)
81; Parameters:
82; AL: Character to convert to lower case
83; BX: Numeric base (2, 10 or 16)
84; Returns:
85; CF: Clear to continue processing
86; Set if error
87; Corrupts registers:
88; AX
89;--------------------------------------------------------------------
90ALIGN JUMP_ALIGN
91StringProcess_ConvertToWordInDIWithBaseInBX:
92 call Char_ConvertIntegerToALfromDigitInALwithBaseInBX
93 jnc SHORT .InvalidCharacter
94 push dx
95
96 xor ah, ah ; Digit converted to integer now in AX
97 xchg ax, di
98 mul bx ; Old WORD *= base
99 jc SHORT .Overflow
100 add di, ax ; Add old WORD to new integer
101 jc SHORT .Overflow
102
103 pop dx
104 ret
105.Overflow:
106 pop dx
107.InvalidCharacter:
108 stc ; Set CF to stop processing
109 ret
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