/
math.c
171 lines (141 loc) · 4.28 KB
/
math.c
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
// Math Instructions ----------------------------------------------------------
// ----------------------------------------------------------------------------
#include "../cpu.h"
// Compare A with REG
#define CMP(REG) static void CMP_##REG() { \
int16_t i = *CPU->A - *CPU->REG; \
*CPU->A = i & 0xff; \
cpu_flag_szp(CPU->A); \
*CPU->F |= i < 0; \
}
CMP(B); CMP(C); CMP(D); CMP(E); CMP(H); CMP(L); CMP(A);
// Compare A with (HL)
static void CMP_M() { \
int16_t i = *CPU->A - read8(*CPU->HL);
*CPU->A = i & 0xff;
cpu_flag_szp(CPU->A);
*CPU->F |= i < 0;
}
// Compare A with next BYTE
static void CPI() {
int16_t i = *CPU->A - read8(*CPU->PC);
*CPU->A = i & 0xff;
cpu_flag_szp(CPU->A);
*CPU->F |= i < 0;
}
// 8 BIT ----------------------------------------------------------------------
// ----------------------------------------------------------------------------
// Add (REG) to A
#define ADD(REG) static void ADD_##REG() { \
uint16_t i = *CPU->A + *CPU->REG; \
*CPU->A = i & 0xff; \
cpu_flag_szap(CPU->A); \
*CPU->F |= i > 0xff; \
}
ADD(B); ADD(C); ADD(D); ADD(E); ADD(H); ADD(L); ADD(A);
// Add contents of (HL) to A
static void ADD_M() { \
uint16_t i = *CPU->A + read8(*CPU->HL);
*CPU->A = i & 0xff; // mask to 255
cpu_flag_szap(CPU->A); // check flags
*CPU->F |= i > 0xff; // set carry flag
}
// Add next BYTE to A
static void ADI() {
uint16_t i = *CPU->A + read8(*CPU->PC);
*CPU->A = i & 0xff;
cpu_flag_szap(CPU->A);
*CPU->F |= i > 0xff;
}
// Add (REG + carry) to A
#define ADC(REG) static void ADC_##REG() { \
uint16_t i = (*CPU->A + *CPU->REG) + (*CPU->F & 1); \
*CPU->A = i & 0xff; \
cpu_flag_szap(CPU->A); \
*CPU->F |= i > 0xff; \
}
ADC(B); ADC(C); ADC(D); ADC(E); ADC(H); ADC(L); ADC(A);
// Add (contents of (HL) + carry) to A
static void ADC_M() {
uint16_t i = (*CPU->A + read8(*CPU->HL)) + (*CPU->F & 1);
*CPU->A = i & 0xff; // mask to 255
cpu_flag_szap(CPU->A); // check flags
*CPU->F |= i > 0xff; // set carry flag
}
// Add next (BYTE + carry) to A
static void ACI() {
uint16_t i = *CPU->A + read8(*CPU->PC)+ (*CPU->F & 1);
*CPU->A = i & 0xff;
cpu_flag_szap(CPU->A);
*CPU->F |= i > 0xff;
}
// Subtract (REG) from A
#define SUB(REG) static void SUB_##REG() { \
int16_t i = *CPU->A - *CPU->REG; \
*CPU->A = i & 0xff; \
cpu_flag_szp(CPU->A); \
*CPU->F |= i < 0; \
}
SUB(B); SUB(C); SUB(D); SUB(E); SUB(H); SUB(L); SUB(A);
// Subtract contents of (HL) from A
static void SUB_M() { \
int16_t i = *CPU->A - read8(*CPU->HL);
*CPU->A = i & 0xff; // mask to 255
cpu_flag_szp(CPU->A); // check flags
*CPU->F |= i < 0; // set carry flag
}
// Subtract next BYTE from A
static void SUI() {
uint16_t i = *CPU->A - read8(*CPU->PC);
*CPU->A = i & 0xff;
cpu_flag_szap(CPU->A);
*CPU->F |= i < 0xff;
}
// Subtract (REG + carry) from A
#define SBB(REG) static void SBB_##REG() { \
int16_t i = (*CPU->A - *CPU->REG) - (*CPU->F & 1); \
*CPU->A = i & 0xff; \
cpu_flag_szp(CPU->A); \
*CPU->F |= i < 0; \
}
SBB(B); SBB(C); SBB(D); SBB(E); SBB(H); SBB(L); SBB(A);
// Subtract (contents of (HL) + carry) from A
static void SBB_M() {
int16_t i = (*CPU->A - read8(*CPU->HL)) - (*CPU->F & 1);
*CPU->A = i & 0xff; // mask to 255
cpu_flag_szp(CPU->A); // check flags
*CPU->F |= i < 0; // set carry flag
}
// Subtract next (BYTE + carry) from A
static void SBI() {
uint16_t i = (*CPU->A - read8(*CPU->PC)) - (*CPU->F & 1);
*CPU->A = i & 0xff;
cpu_flag_szap(CPU->A);
*CPU->F |= i < 0xff;
}
// 16 BIT ---------------------------------------------------------------------
// ----------------------------------------------------------------------------
// Add BC to HL
static void DAD_B() {
uint32_t i = *CPU->HL + *CPU->BC;
*CPU->F = i > 0xffff; // Carry is bit 1, so this clears and sets correctly
*CPU->HL = (i & 0xffff);
}
// Add DE to HL
static void DAD_D() {
uint32_t i = *CPU->HL + *CPU->DE;
*CPU->F = i > 0xffff;
*CPU->HL = (i & 0xffff);
}
// Add HL to HL
static void DAD_H() {
uint32_t i = *CPU->HL + *CPU->HL;
*CPU->F = i > 0xffff;
*CPU->HL = (i & 0xffff);
}
// Add SP to HL
static void DAD_SP() {
uint32_t i = *CPU->HL + *CPU->SP;
*CPU->F = i > 0xffff;
*CPU->HL = (i & 0xffff);
}