-
Notifications
You must be signed in to change notification settings - Fork 11
/
CPU+AddressingModes.swift
107 lines (78 loc) · 2.52 KB
/
CPU+AddressingModes.swift
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
import Foundation
internal extension CPU {
func absolute() -> Address {
advanceProgramCounter()
}
func absolute() -> UInt8 {
read(advanceProgramCounter())
}
func absoluteX(_ incursPageBoundaryCost: Bool = false) -> Address {
let address = advanceProgramCounter() &+ Address(x)
if incursPageBoundaryCost && differentPages(address, address &- Address(x)) {
cycles += 1
}
return address
}
func absoluteX(_ incursPageBoundaryCost: Bool = false) -> UInt8 {
read(absoluteX(incursPageBoundaryCost))
}
func absoluteY(_ incursPageBoundaryCost: Bool = false) -> Address {
let address = advanceProgramCounter() &+ Address(y)
if incursPageBoundaryCost && differentPages(address, address &- Address(y)) {
cycles += 1
}
return address
}
func absoluteY(_ incursPageBoundaryCost: Bool = false) -> UInt8 {
read(absoluteY(incursPageBoundaryCost))
}
func accumulator() -> Void {
}
func immediate() -> UInt8 {
advanceProgramCounter()
}
func implied() -> Void {
}
func indexedIndirect() -> Address {
let address = Address(advanceProgramCounter() &+ x)
return buggyRead16(address)
}
func indexedIndirect() -> UInt8 {
read(indexedIndirect())
}
func indirect() -> Address {
buggyRead16(advanceProgramCounter())
}
func indirectIndexed(_ incursPageBoundaryCost: Bool = false) -> Address {
let address = buggyRead16(Address(page: 0x00, offset: advanceProgramCounter())) &+ Address(y)
if incursPageBoundaryCost && differentPages(address, address &- Address(y)) {
cycles += 1
}
return address
}
func indirectIndexed(_ incursPageBoundaryCost: Bool = false) -> UInt8 {
read(indirectIndexed(incursPageBoundaryCost))
}
func relative() -> UInt8 {
advanceProgramCounter()
}
func zeroPage() -> UInt8 {
let address = Address(page: 0, offset: advanceProgramCounter())
return read(address)
}
func zeroPage() -> Address {
Address(page: 0, offset: advanceProgramCounter())
}
func zeroPageX() -> Address {
Address(page: 0, offset: advanceProgramCounter() &+ x)
}
func zeroPageX() -> UInt8 {
read(zeroPageX())
}
func zeroPageY() -> Address {
Address(page: 0, offset: advanceProgramCounter() &+ y)
}
func zeroPageY() -> UInt8 {
read(zeroPageY())
}
}