blob: 81db1b0640b2fd13e4d74f5144e127acf89539f2 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
|
package cpu
import BitManipulation as bm
class Registers {
// General purpose registers
var B: Int = 0
set(value) {
bm.validateUnsigned8Bit(value)
field = value
}
var C: Int = 0
set(value) {
bm.validateUnsigned8Bit(value)
field = value
}
var D: Int = 0
set(value) {
bm.validateUnsigned8Bit(value)
field = value
}
var E: Int = 0
set(value) {
bm.validateUnsigned8Bit(value)
field = value
}
var H: Int = 0
set(value) {
bm.validateUnsigned8Bit(value)
field = value
}
var L: Int = 0
set(value) {
bm.validateUnsigned8Bit(value)
field = value
}
// Special registers
var A: Int = 0
set(value) {
bm.validateUnsigned8Bit(value)
field = value
}
var F: Int = 0
set(value) {
bm.validateUnsigned8Bit(value)
field = value
}
var SP: Int = 0
set(value) {
bm.validateUnsigned16Bit(value)
field = value
}
var PC: Int = 0
set(value) {
bm.validateUnsigned16Bit(value)
field = value
}
// 16-Bit accessors
var AF: Int
get() {
return bm.bytesToWord(A, F)
}
set(value) {
bm.validateUnsigned16Bit(value)
A = bm.getMsb(value)
F = bm.getLsb(value)
}
var BC: Int
get() {
return bm.bytesToWord(B, C)
}
set(value) {
bm.validateUnsigned16Bit(value)
B = bm.getMsb(value)
C = bm.getLsb(value)
}
var DE: Int
get() {
return bm.bytesToWord(D, E)
}
set(value) {
bm.validateUnsigned16Bit(value)
D = bm.getMsb(value)
E = bm.getLsb(value)
}
var HL: Int
get() {
return bm.bytesToWord(H, L)
}
set(value) {
bm.validateUnsigned16Bit(value)
H = bm.getMsb(value)
L = bm.getLsb(value)
}
fun getAndDecrementHL(): Int {
val currentHL = HL
if(HL > 0x0000) { // TODO - is this correct? Or should it underflow to 0xFFFF?. Also for increment op.
HL--
}
return currentHL
}
fun getAndIncrementHL(): Int {
val currentHL = HL
if(HL < 0xFFFF) {
HL++
}
return currentHL
}
fun decrementAndGetSP(): Int {
return if(SP > 0x0000) {
--SP
} else {
SP
}
}
fun getAndIncrementSP(): Int {
val currentSP = SP
if(SP < 0xFFFF) {
SP++
}
return currentSP
}
fun addSignedByteToPC(byte: Int) {
PC = if (bm.isSignedByteNegative(byte)) {
(PC - bm.getAbsoluteValue(byte)) and 0xFFFF
} else {
(PC + bm.getAbsoluteValue(byte)) and 0xFFFF
}
}
fun getFlag(flag: Flag): Int {
return (F shr flag.bitPosition) and 0x01
}
fun setFlag(flag: Flag) {
F = F or (1 shl flag.bitPosition)
}
fun clearFlag(flag: Flag) {
F = F and (1 shl flag.bitPosition).inv()
}
fun setFlagFromBool(flag: Flag, isSet: Boolean) {
if(isSet) {
setFlag(flag)
}
else {
clearFlag(flag)
}
}
fun clearFlags() {
F = 0x00
}
enum class Flag(val bitPosition: Int) {
ZERO(7),
SUBTRACT(6),
HALF_CARRY(5),
CARRY(4),
}
}
|