-
Notifications
You must be signed in to change notification settings - Fork 3
/
main.lua
325 lines (246 loc) · 5.59 KB
/
main.lua
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
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
require "helper"
require "bit"
-- 16 keys
keys = {}
keys["1"] = 1
keys["2"] = 2
keys["3"] = 3
keys["q"] = 4
keys["w"] = 5
keys["e"] = 6
keys["a"] = 7
keys["s"] = 8
keys["d"] = 9
keys["y"] = 10
keys["x"] = 0
keys["c"] = 11
keys["4"] = 12
keys["r"] = 13
keys["f"] = 14
keys["v"] = 15
input = {}
function love.keypressed(key)
if key == "escape" then
love.event.quit()
end
for k, v in pairs(keys) do
if key == k then
input[v] = true
end
end
end
function love.keyreleased(key)
for k, v in pairs(keys) do
if key == k then
input[v] = false
end
end
end
function love.load()
local game = arg[2]
if game == nil then
print("game parameter missing")
love.event.quit()
return
end
love.mouse.setVisible(false)
-- prepare memory
mem = { 0xF0, 0x90, 0x90, 0x90, 0xF0, 0x20, 0x60, 0x20, 0x20, 0x70,
0xF0, 0x10, 0xF0, 0x80, 0xF0, 0xF0, 0x10, 0xF0, 0x10, 0xF0, 0x90,
0x90, 0xF0, 0x10, 0x10, 0xF0, 0x80, 0xF0, 0x10, 0xF0, 0xF0, 0x80,
0xF0, 0x90, 0xF0, 0xF0, 0x10, 0x20, 0x40, 0x40, 0xF0, 0x90, 0xF0,
0x90, 0xF0, 0xF0, 0x90, 0xF0, 0x10, 0xF0, 0xF0, 0x90, 0xF0, 0x90,
0x90, 0xE0, 0x90, 0xE0, 0x90, 0xE0, 0xF0, 0x80, 0x80, 0x80, 0xF0,
0xE0, 0x90, 0x90, 0x90, 0xE0, 0xF0, 0x80, 0xF0, 0x80, 0xF0, 0xF0,
0x80, 0xF0, 0x80, 0x80 }
local i = 0x200
for b in io.open(game):read("*a"):gmatch(".") do
mem[i] = string.byte(b)
i = i + 1
end
while i < 0x1000 do
mem[i] = 0
i = i + 1
end
reg = {}
for i = 0, 15 do
reg[i] = 0
end
reg.I = 0
reg.C = 0x200
reg.D = 0
reg.S = 0
stack = {}
display = {}
for i = 0, 64 * 32 - 1 do
display[i] = 0
end
end
function love.update(dt)
-- love.timer.sleep((1 - dt) * 1000 / 60) -- doesn't work \:
end
function cycle()
local ab = mem[reg.C]
local cd = mem[reg.C + 1]
local op = ab * 256 + cd
local a = math.floor(ab / 16)
local b = ab % 16
local c = math.floor(cd / 16)
local d = cd % 16
reg.C = reg.C + 2
if op == 0x00e0 then -- clear screen
for i = 0, 64 * 32 - 1 do
display[i] = 0
end
elseif op == 0x00ee then -- return
reg.C = stack[#stack]
stack[#stack] = nil
elseif a == 1 then -- jump
reg.C = b * 256 + cd
elseif a == 2 then -- call
stack[#stack + 1] = reg.C
reg.C = b * 256 + cd
elseif a == 3 then -- skip
if reg[b] == cd then
reg.C = reg.C + 2
end
elseif a == 4 then -- skip
if reg[b] ~= cd then
reg.C = reg.C + 2
end
elseif a == 5 and d == 0 then -- skip
if reg[b] == reg[c] then
reg.C = reg.C + 2
end
elseif a == 6 then -- set
reg[b] = cd
elseif a == 7 then -- add
reg[b] = (reg[b] + cd) % 256
elseif a == 8 then
if d == 0 then -- set
reg[b] = reg[c]
elseif d == 1 then -- or
reg[b] = bit.bor(reg[b], reg[c])
elseif d == 2 then -- and
reg[b] = bit.band(reg[b], reg[c])
elseif d == 3 then -- xor
reg[b] = bit.bxor(reg[b], reg[c])
elseif d == 4 then -- add
reg[b] = (reg[b] + reg[c]) % 256
reg[15] = reg[b] + reg[c] >= 256 and 1 or 0
elseif d == 5 then -- sub
reg[15] = reg[b] <= reg[c] and 0 or 1
reg[b] = (reg[b] - reg[c] + 256) % 256
elseif d == 6 then -- shr
reg[15] = reg[b] % 2
reg[b] = math.floor(reg[b] / 2)
elseif d == 7 then -- subn
reg[15] = reg[c] <= reg[b] and 0 or 1
reg[b] = (reg[c] - reg[b] + 256) % 256
elseif d == 0xe then -- shr
reg[15] = math.floor(reg[b] / 128)
reg[b] = (reg[b] * 2) % 256
else
print(a, b, c, d)
end
elseif a == 9 and d == 0 then -- sne
if reg[b] ~= reg[c] then
reg.C = reg.C + 2
end
elseif a == 0xa then -- sne
reg.I = b * 256 + cd
elseif a == 0xb then -- jp
reg.C = (b * 256 + cd + reg[0]) % 0x1000
elseif a == 0xc then -- rnd
reg[b] = bit.band(math.random(0, 255), cd)
elseif a == 0xd then -- drw
local x = reg[b]
local y = reg[c]
reg[15] = 0
for i = 0, d - 1 do
local m = mem[reg.I + i]
for j = 0, 7 do
if bit.band(m, 2 ^ (7 - j)) > 0 then
local q = display[(x + j) % 64 + ((y + i) % 32) * 64]
if q == 1 then
reg[15] = 1
end
display[(x + j) % 64 + ((y + i) % 32) * 64] = 1 - q
end
end
end
elseif a == 0xe then
if cd == 0x9e then -- skp
if input[reg[b]] then
reg.C = reg.C + 2
end
elseif cd == 0xa1 then -- skp
if not input[reg[b]] then
reg.C = reg.C + 2
end
else
print(a, b, c, d)
end
-- TODO: more opcodes...
elseif a == 0xf then
if cd == 0x07 then -- timer
reg[b] = reg.D
if reg.D > 0 then
reg.D = reg.D - 1
return true
end
elseif cd == 0x0a then -- wait for key
reg.C = reg.C - 2
for i = 0, 15 do
if input[i] then
reg[b] = i
reg.C = reg.C + 2
break
end
end
elseif cd == 0x15 then -- timer
reg.D = reg[b]
elseif cd == 0x18 then -- timer
reg.S = reg[b]
elseif cd == 0x1e then
reg.I = (reg.I + reg[b]) % 0x1000
elseif cd == 0x29 then -- ld
reg.I = reg[b] * 5 + 1
elseif cd == 0x33 then -- bcd stuff
mem[reg.I + 0] = math.floor(reg[b] / 100)
mem[reg.I + 1] = math.floor(reg[b] / 10) % 10
mem[reg.I + 2] = reg[b] % 10
elseif cd == 0x55 then -- ld
for i = 0, b do
mem[reg.I + i] = reg[i]
end
reg.I = reg.I + b + 1
elseif cd == 0x65 then -- ld
for i = 0, b do
reg[i] = mem[reg.I + i]
end
reg.I = reg.I + b + 1
else
print(a, b, c, d)
end
else
print(a, b, c, d)
end
end
function love.draw()
-- testing
for i = 1, 15 do
if cycle() then
break
end
end
-- render display
for i = 0, 64 * 32 - 1 do
local x = i % 64
local y = math.floor(i / 64)
local b = display[i]
local color = b == 1 and { 255, 255, 255 } or { 0, 0, 0 }
love.graphics.setColor(unpack(color))
love.graphics.rectangle("fill", x * 4, y * 4, 4, 4)
end
end