source: xtideuniversalbios/trunk/Assembly_Library/Src/Util/Registers.asm@ 103

Last change on this file since 103 was 103, checked in by krille_n_@…, 14 years ago

Optimizations to Assembly Library.
File size: 2.9 KB
Line 
1; Project name : Assembly Library
2; Description : Functions for register operations.
3
4;--------------------------------------------------------------------
5; NORMALIZE_FAR_POINTER
6; Parameters:
7; %1:%2: Far pointer to normalize
8; %3: Scratch register
9; %4: Scratch register
10; Returns:
11; %1:%2: Normalized far pointer
12; Corrupts registers:
13; %3, %4
14;--------------------------------------------------------------------
15%macro NORMALIZE_FAR_POINTER 4
16 mov %4, %2 ; Copy offset to scratch reg
17 and %2, BYTE 0Fh ; Clear offset bits 15...4
18 eSHR_IM %4, 4 ; Divide offset by 16
19 mov %3, %1 ; Copy segment to scratch reg
20 add %3, %4 ; Add shifted offset to segment
21 mov %1, %3 ; Set normalized segment
22%endmacro
23
24
25; Section containing code
26SECTION .text
27
28;--------------------------------------------------------------------
29; Registers_NormalizeDSSI
30; Registers_NormalizeESDI
31; Parameters
32; DS:SI or ES:DI: Ptr to normalize
33; Returns:
34; DS:SI or ES:DI: Normalized pointer
35; Corrupts registers:
36; Nothing
37;--------------------------------------------------------------------
38ALIGN JUMP_ALIGN
39Registers_NormalizeDSSI:
40 push dx
41 push ax
42 NORMALIZE_FAR_POINTER ds, si, ax, dx
43 pop ax
44 pop dx
45 ret
46
47ALIGN JUMP_ALIGN
48Registers_NormalizeESDI:
49 push dx
50 push ax
51 NORMALIZE_FAR_POINTER es, di, ax, dx
52 pop ax
53 pop dx
54 ret
55
56
57;--------------------------------------------------------------------
58; Registers_ExchangeDSSIwithESDI
59; Parameters
60; Nothing
61; Returns:
62; DS:SI and ES:DI are exchanged.
63; Corrupts registers:
64; Nothing
65;--------------------------------------------------------------------
66ALIGN JUMP_ALIGN
67Registers_ExchangeDSSIwithESDI:
68 push ds
69 push es
70 pop ds
71 pop es
72 xchg si, di
73 ret
74
75
76;--------------------------------------------------------------------
77; Registers_CopySSBPtoESDI
78; Registers_CopySSBPtoDSSI
79; Registers_CopyDSSItoESDI
80; Registers_CopyESDItoDSSI
81; Parameters
82; Nothing
83; Returns:
84; Copies farm pointer to different segment/pointer register pair
85; Corrupts registers:
86; Nothing
87;--------------------------------------------------------------------
88%macro Registers_CopySSBPtoESDI 0
89 push ss
90 pop es
91 mov di, bp
92%endmacro
93
94%macro Registers_CopySSBPtoDSSI 0
95 push ss
96 pop ds
97 mov si, bp
98%endmacro
99
100%macro Registers_CopyDSSItoESDI 0
101 push ds
102 pop es
103 mov di, si
104%endmacro
105
106%macro Registers_CopyESDItoDSSI 0
107 push es
108 pop ds
109 mov si, di
110%endmacro
111
112
113;--------------------------------------------------------------------
114; Registers_SetZFifNullPointerInDSSI
115; Parameters
116; DS:SI: Far pointer
117; Returns:
118; ZF: Set if NULL pointer in DS:SI
119; Corrupts registers:
120; Nothing
121;--------------------------------------------------------------------
122ALIGN JUMP_ALIGN
123Registers_SetZFifNullPointerInDSSI:
124 push ax
125 mov ax, ds
126 or ax, si
127 pop ax
128 ret
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