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
|
#!/usr/bin/env python3
import sys
if len(sys.argv) != 2:
print(f"Usage: {sys.argv[0]} [filename]")
sys.exit(1)
def decode_jump(ins: int) -> str:
if (ins & 0x7) == 0:
return ""
if (ins & 0x7) == 0x7:
return "; j"
jl = (ins & (1 << 2)) != 0
je = (ins & (1 << 1)) != 0
jg = (ins & (1 << 0)) != 0
# implied: and not jg
if jl and je:
return "; jle"
# implied: and not je
if jl and jg:
return "; jne"
# implied: and not je
if je and jg:
return "; jge"
# implied: only one flag is 1
if jl:
return "; jl"
if je:
return "; je"
if jg:
return "; jg"
return "; <unknown>"
# return op, and whether it's a one-op or two-op
def decode_ins(ins: int) -> (str, bool):
opcode = (ins >> 8) & 0x03
ar_n_log = (ins & (1 << 10)) != 0
opcode |= ar_n_log << 2
if opcode == 0b000:
return "and", True
if opcode == 0b001:
return "or", True
if opcode == 0b010:
return "xor", True
if opcode == 0b011:
return "neg", False
if opcode == 0b100:
return "add", True
if opcode == 0b101:
return "inc", False
if opcode == 0b110:
return "sub", True
if opcode == 0b111:
return "dec", False
return "<?>"
# normally, X = arg1 = D
def decode_arg1(ins: int) -> str:
use_mem = (ins & (1 << 12)) != 0
zx = (ins & (1 << 7)) != 0
sw = (ins & (1 << 6)) != 0
if zx:
return "0"
# and not sw?
# zx and swap: don't care, other arg is zeroed
if not zx and not sw and not use_mem:
return "A"
if not zx and not sw and use_mem:
return "M"
return "?"
# normally, Y = arg2 = A
def decode_arg2(ins: int) -> str:
use_mem = (ins & (1 << 12)) != 0
zx = (ins & (1 << 7)) != 0
sw = (ins & (1 << 6)) != 0
if zx and sw:
return "0"
# zx and not swap: don't care, other arg is zeroed
# zx ???
if sw and not use_mem:
return "A"
if sw and use_mem:
return "M"
return "?"
def decode_dest(ins: int) -> str:
dA = (ins & (1 << 5)) != 0
dD = (ins & (1 << 4)) != 0
dM = (ins & (1 << 3)) != 0
dest_s = ""
if dA:
dest_s += "A "
if dD:
dest_s += "D "
if dM:
dest_s += "M"
if dest_s:
dest_s += ", "
return dest_s
def decode(ins: int) -> str:
if ins & 0x8000 == 0:
# mov? ldr? ldi? aaaaaaaaaaa....
return f"mov A, #{ins}"
else:
dest_s = decode_dest(ins)
codename, two_op = decode_ins(ins)
op1 = decode_arg1(ins)
op2 = decode_arg2(ins)
op2_s = f", {op2}" if two_op else ""
return f"{codename:<5}{dest_s:<8}{op1:<3}{op2_s:<5}{decode_jump(ins)}"
def main():
try:
with open(sys.argv[1], "rb") as f:
while True:
insb = f.read(2)
if not insb:
break
ins = int.from_bytes(insb)
print(f"\t{insb[0]:02x} {insb[1]:02x}\t{decode(ins)}")
except FileNotFoundError:
print(f"File not found.")
sys.exit(1)
# head, tail...
except BrokenPipeError:
sys.exit(0)
if __name__ == "__main__":
main()
|
