1 | ; File name : Registers.asm |
---|
2 | ; Project name : Assembly Library |
---|
3 | ; Created date : 24.10.2010 |
---|
4 | ; Last update : 6.12.2010 |
---|
5 | ; Author : Tomi Tilli |
---|
6 | ; Description : Functions for register operations. |
---|
7 | |
---|
8 | ;-------------------------------------------------------------------- |
---|
9 | ; NORMALIZE_FAR_POINTER |
---|
10 | ; Parameters: |
---|
11 | ; %1:%2: Far pointer to normalize |
---|
12 | ; %3: Scratch register |
---|
13 | ; %4: Scratch register |
---|
14 | ; Returns: |
---|
15 | ; %1:%2: Normalized far pointer |
---|
16 | ; Corrupts registers: |
---|
17 | ; %3, %4 |
---|
18 | ;-------------------------------------------------------------------- |
---|
19 | %macro NORMALIZE_FAR_POINTER 4 |
---|
20 | mov %4, %2 ; Copy offset to scratch reg |
---|
21 | and %2, BYTE 0Fh ; Clear offset bits 15...4 |
---|
22 | eSHR_IM %4, 4 ; Divide offset by 16 |
---|
23 | mov %3, %1 ; Copy segment to scratch reg |
---|
24 | add %3, %4 ; Add shifted offset to segment |
---|
25 | mov %1, %3 ; Set normalized segment |
---|
26 | %endmacro |
---|
27 | |
---|
28 | |
---|
29 | ; Section containing code |
---|
30 | SECTION .text |
---|
31 | |
---|
32 | ;-------------------------------------------------------------------- |
---|
33 | ; Registers_NormalizeDSSI |
---|
34 | ; Registers_NormalizeESDI |
---|
35 | ; Parameters |
---|
36 | ; DS:SI or ES:DI: Ptr to normalize |
---|
37 | ; Returns: |
---|
38 | ; DS:SI or ES:DI: Normalized pointer |
---|
39 | ; Corrupts registers: |
---|
40 | ; Nothing |
---|
41 | ;-------------------------------------------------------------------- |
---|
42 | ALIGN JUMP_ALIGN |
---|
43 | Registers_NormalizeDSSI: |
---|
44 | push dx |
---|
45 | push ax |
---|
46 | NORMALIZE_FAR_POINTER ds, si, ax, dx |
---|
47 | pop ax |
---|
48 | pop dx |
---|
49 | ret |
---|
50 | |
---|
51 | ALIGN JUMP_ALIGN |
---|
52 | Registers_NormalizeESDI: |
---|
53 | push dx |
---|
54 | push ax |
---|
55 | NORMALIZE_FAR_POINTER es, di, ax, dx |
---|
56 | pop ax |
---|
57 | pop dx |
---|
58 | ret |
---|
59 | |
---|
60 | |
---|
61 | ;-------------------------------------------------------------------- |
---|
62 | ; Registers_ExchangeDSSIwithESDI |
---|
63 | ; Parameters |
---|
64 | ; Nothing |
---|
65 | ; Returns: |
---|
66 | ; DS:SI and ES:DI are exchanged. |
---|
67 | ; Corrupts registers: |
---|
68 | ; Nothing |
---|
69 | ;-------------------------------------------------------------------- |
---|
70 | ALIGN JUMP_ALIGN |
---|
71 | Registers_ExchangeDSSIwithESDI: |
---|
72 | push ds |
---|
73 | push es |
---|
74 | pop ds |
---|
75 | pop es |
---|
76 | xchg si, di |
---|
77 | ret |
---|
78 | |
---|
79 | |
---|
80 | ;-------------------------------------------------------------------- |
---|
81 | ; Registers_CopySSBPtoESDI |
---|
82 | ; Registers_CopySSBPtoDSSI |
---|
83 | ; Registers_CopyDSSItoESDI |
---|
84 | ; Registers_CopyESDItoDSSI |
---|
85 | ; Parameters |
---|
86 | ; Nothing |
---|
87 | ; Returns: |
---|
88 | ; Copies farm pointer to different segment/pointer register pair |
---|
89 | ; Corrupts registers: |
---|
90 | ; Nothing |
---|
91 | ;-------------------------------------------------------------------- |
---|
92 | ALIGN JUMP_ALIGN |
---|
93 | Registers_CopySSBPtoESDI: |
---|
94 | push ss |
---|
95 | pop es |
---|
96 | mov di, bp |
---|
97 | ret |
---|
98 | |
---|
99 | ALIGN JUMP_ALIGN |
---|
100 | Registers_CopySSBPtoDSSI: |
---|
101 | push ss |
---|
102 | pop ds |
---|
103 | mov si, bp |
---|
104 | ret |
---|
105 | |
---|
106 | ALIGN JUMP_ALIGN |
---|
107 | Registers_CopyDSSItoESDI: |
---|
108 | push ds |
---|
109 | pop es |
---|
110 | mov di, si |
---|
111 | ret |
---|
112 | |
---|
113 | ALIGN JUMP_ALIGN |
---|
114 | Registers_CopyESDItoDSSI: |
---|
115 | push es |
---|
116 | pop ds |
---|
117 | mov si, di |
---|
118 | ret |
---|
119 | |
---|
120 | |
---|
121 | ;-------------------------------------------------------------------- |
---|
122 | ; Registers_SetZFifNullPointerInDSSI |
---|
123 | ; Parameters |
---|
124 | ; DS:SI: Far pointer |
---|
125 | ; Returns: |
---|
126 | ; ZF: Set if NULL pointer in DS:SI |
---|
127 | ; Corrupts registers: |
---|
128 | ; Nothing |
---|
129 | ;-------------------------------------------------------------------- |
---|
130 | ALIGN JUMP_ALIGN |
---|
131 | Registers_SetZFifNullPointerInDSSI: |
---|
132 | push ax |
---|
133 | mov ax, ds |
---|
134 | or ax, si |
---|
135 | pop ax |
---|
136 | ret |
---|