-
Notifications
You must be signed in to change notification settings - Fork 19
/
memory_access.go
414 lines (346 loc) · 10.3 KB
/
memory_access.go
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
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
// This file is part of Gopher2600.
//
// Gopher2600 is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Gopher2600 is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Gopher2600. If not, see <https://www.gnu.org/licenses/>.
package arm
import (
"fmt"
"github.com/jetsetilly/gopher2600/logger"
)
func (arm *ARM) illegalAccess(event string, addr uint32) {
arm.memoryError = fmt.Errorf("%s: unrecognised address %08x (PC: %08x)", event, addr, arm.state.instructionPC)
if arm.dev == nil {
return
}
detail := arm.dev.IllegalAccess(event, arm.state.instructionPC, addr)
if detail == "" {
return
}
arm.memoryErrorDetail = fmt.Errorf("%s: %s", event, detail)
}
// nullAccess is a special condition of illegalAccess()
func (arm *ARM) nullAccess(event string, addr uint32) {
arm.memoryError = fmt.Errorf("%s: probable null pointer dereference of %08x (PC: %08x)", event, addr, arm.state.instructionPC)
if arm.dev == nil {
return
}
detail := arm.dev.NullAccess(event, arm.state.instructionPC, addr)
if detail == "" {
return
}
arm.memoryErrorDetail = fmt.Errorf("%s: %s", event, detail)
}
// imperfect check of whether stack has collided with memtop
func (arm *ARM) stackCollision(stackPointerBeforeExecution uint32) (err error, detail error) {
if arm.stackHasCollided || stackPointerBeforeExecution == arm.state.registers[rSP] {
return
}
// check if stackMemory point and memtop are in the same memory block
stackMemory, _ := arm.mem.MapAddress(arm.state.registers[rSP], true)
variableMemory, _ := arm.mem.MapAddress(arm.variableMemtop, true)
// check if the memory block and "variables" are in the same
// memory block and that the stack pointer is below the top of
// variable memory
if stackMemory != variableMemory || arm.state.registers[rSP] > arm.variableMemtop {
return
}
// set stackHasCollided flag. this means that memory accesses
// will no longer be checked for legality
arm.stackHasCollided = true
err = fmt.Errorf("stack: collision with program memory (%08x)", arm.state.registers[rSP])
if arm.dev != nil {
return
}
detailStr := arm.dev.StackCollision(arm.state.executingPC, arm.state.registers[rSP])
if detailStr == "" {
return
}
detail = fmt.Errorf("stack: %s", detailStr)
return err, detail
}
func (arm *ARM) read8bit(addr uint32) uint8 {
if addr < arm.mmap.NullAccessBoundary {
arm.nullAccess("Read 8bit", addr)
}
var mem *[]uint8
mem, addr = arm.mem.MapAddress(addr, false)
if mem == nil {
if arm.mmap.HasMAM {
if v, ok, comment := arm.state.mam.Read(addr); ok {
arm.disasmExecutionNotes = comment
return uint8(v)
}
}
if arm.mmap.HasRNG {
if v, ok, comment := arm.state.rng.Read(addr); ok {
arm.disasmExecutionNotes = comment
return uint8(v)
}
}
if arm.mmap.HasTIMER {
if v, ok, comment := arm.state.timer.Read(addr); ok {
arm.disasmExecutionNotes = comment
return uint8(v)
}
}
if arm.mmap.HasTIM2 {
if v, ok, comment := arm.state.timer2.Read(addr); ok {
arm.disasmExecutionNotes = comment
return uint8(v)
}
}
if !arm.stackHasCollided {
arm.illegalAccess("Read 8bit", addr)
}
return uint8(arm.mmap.IllegalAccessValue)
}
return (*mem)[addr]
}
func (arm *ARM) write8bit(addr uint32, val uint8) {
if addr < arm.mmap.NullAccessBoundary {
arm.nullAccess("Write 8bit", addr)
}
var mem *[]uint8
mem, addr = arm.mem.MapAddress(addr, true)
if mem == nil {
if arm.mmap.HasMAM {
if ok, comment := arm.state.mam.Write(addr, uint32(val)); ok {
arm.disasmExecutionNotes = comment
return
}
}
if arm.mmap.HasRNG {
if ok, comment := arm.state.rng.Write(addr, uint32(val)); ok {
arm.disasmExecutionNotes = comment
return
}
}
if arm.mmap.HasTIMER {
if ok, comment := arm.state.timer.Write(addr, uint32(val)); ok {
arm.disasmExecutionNotes = comment
return
}
}
if arm.mmap.HasTIM2 {
if ok, comment := arm.state.timer2.Write(addr, uint32(val)); ok {
arm.disasmExecutionNotes = comment
return
}
}
if !arm.stackHasCollided {
arm.illegalAccess("Write 8bit", addr)
}
return
}
(*mem)[addr] = val
}
func (arm *ARM) read16bit(addr uint32, requiresAlignment bool) uint16 {
if addr < arm.mmap.NullAccessBoundary {
arm.nullAccess("Read 16bit", addr)
}
// check 16 bit alignment
misaligned := addr&0x01 != 0x00
if misaligned && (requiresAlignment || arm.mmap.UnalignTrap) {
logger.Logf("ARM7", "misaligned 16 bit read (%08x) (PC: %08x)", addr, arm.state.registers[rPC])
}
var mem *[]uint8
mem, addr = arm.mem.MapAddress(addr, false)
if mem == nil {
if arm.mmap.HasMAM {
if v, ok, comment := arm.state.mam.Read(addr); ok {
arm.disasmExecutionNotes = comment
return uint16(v)
}
}
if arm.mmap.HasRNG {
if v, ok, comment := arm.state.rng.Read(addr); ok {
arm.disasmExecutionNotes = comment
return uint16(v)
}
}
if arm.mmap.HasTIMER {
if v, ok, comment := arm.state.timer.Read(addr); ok {
arm.disasmExecutionNotes = comment
return uint16(v)
}
}
if arm.mmap.HasTIM2 {
if v, ok, comment := arm.state.timer2.Read(addr); ok {
arm.disasmExecutionNotes = comment
return uint16(v)
}
}
if !arm.stackHasCollided {
arm.illegalAccess("Read 16bit", addr)
}
return uint16(arm.mmap.IllegalAccessValue)
}
// ensure we're not accessing past the end of memory
if len(*mem) < 2 || addr >= uint32(len(*mem)-1) {
arm.illegalAccess("Read 16bit", addr)
return uint16(arm.mmap.IllegalAccessValue)
}
return arm.byteOrder.Uint16((*mem)[addr:])
// return uint16((*mem)[addr]) | (uint16((*mem)[addr+1]) << 8)
}
func (arm *ARM) write16bit(addr uint32, val uint16, requiresAlignment bool) {
if addr < arm.mmap.NullAccessBoundary {
arm.nullAccess("Write 16bit", addr)
}
// check 16 bit alignment
misaligned := addr&0x01 != 0x00
if misaligned && (requiresAlignment || arm.mmap.UnalignTrap) {
logger.Logf("ARM7", "misaligned 16 bit write (%08x) (PC: %08x)", addr, arm.state.registers[rPC])
}
var mem *[]uint8
mem, addr = arm.mem.MapAddress(addr, true)
if mem == nil {
if arm.mmap.HasMAM {
if ok, comment := arm.state.mam.Write(addr, uint32(val)); ok {
arm.disasmExecutionNotes = comment
return
}
}
if arm.mmap.HasRNG {
if ok, comment := arm.state.rng.Write(addr, uint32(val)); ok {
arm.disasmExecutionNotes = comment
return
}
}
if arm.mmap.HasTIMER {
if ok, comment := arm.state.timer.Write(addr, uint32(val)); ok {
arm.disasmExecutionNotes = comment
return
}
}
if arm.mmap.HasTIM2 {
if ok, comment := arm.state.timer2.Write(addr, uint32(val)); ok {
arm.disasmExecutionNotes = comment
return
}
}
if !arm.stackHasCollided {
arm.illegalAccess("Write 16bit", addr)
}
return
}
// ensure we're not accessing past the end of memory
if len(*mem) < 2 || addr >= uint32(len(*mem)-1) {
arm.illegalAccess("Write 16bit", addr)
return
}
arm.byteOrder.PutUint16((*mem)[addr:], val)
// (*mem)[addr] = uint8(val)
// (*mem)[addr+1] = uint8(val >> 8)
}
func (arm *ARM) read32bit(addr uint32, requiresAlignment bool) uint32 {
if addr < arm.mmap.NullAccessBoundary {
arm.nullAccess("Read 32bit", addr)
}
// check 32 bit alignment
misaligned := addr&0x03 != 0x00
if misaligned && (requiresAlignment || arm.mmap.UnalignTrap) {
logger.Logf("ARM7", "misaligned 32 bit read (%08x) (PC: %08x)", addr, arm.state.registers[rPC])
}
var mem *[]uint8
mem, addr = arm.mem.MapAddress(addr, false)
if mem == nil {
if arm.mmap.HasMAM {
if v, ok, comment := arm.state.mam.Read(addr); ok {
arm.disasmExecutionNotes = comment
return uint32(v)
}
}
if arm.mmap.HasRNG {
if v, ok, comment := arm.state.rng.Read(addr); ok {
arm.disasmExecutionNotes = comment
return uint32(v)
}
}
if arm.mmap.HasTIMER {
if v, ok, comment := arm.state.timer.Read(addr); ok {
arm.disasmExecutionNotes = comment
return uint32(v)
}
}
if arm.mmap.HasTIM2 {
if v, ok, comment := arm.state.timer2.Read(addr); ok {
arm.disasmExecutionNotes = comment
return uint32(v)
}
}
if !arm.stackHasCollided {
arm.illegalAccess("Read 32bit", addr)
}
return arm.mmap.IllegalAccessValue
}
// ensure we're not accessing past the end of memory
if len(*mem) < 4 || addr >= uint32(len(*mem)-3) {
arm.illegalAccess("Read 32bit", addr)
return arm.mmap.IllegalAccessValue
}
return arm.byteOrder.Uint32((*mem)[addr:])
// return uint32((*mem)[addr]) | (uint32((*mem)[addr+1]) << 8) | (uint32((*mem)[addr+2]) << 16) | uint32((*mem)[addr+3])<<24
}
func (arm *ARM) write32bit(addr uint32, val uint32, requiresAlignment bool) {
if addr < arm.mmap.NullAccessBoundary {
arm.nullAccess("Write 32bit", addr)
}
// check 32 bit alignment
misaligned := addr&0x03 != 0x00
if misaligned && (requiresAlignment || arm.mmap.UnalignTrap) {
logger.Logf("ARM7", "misaligned 32 bit write (%08x) (PC: %08x)", addr, arm.state.registers[rPC])
}
var mem *[]uint8
mem, addr = arm.mem.MapAddress(addr, true)
if mem == nil {
if arm.mmap.HasMAM {
if ok, comment := arm.state.mam.Write(addr, uint32(val)); ok {
arm.disasmExecutionNotes = comment
return
}
}
if arm.mmap.HasRNG {
if ok, comment := arm.state.rng.Write(addr, uint32(val)); ok {
arm.disasmExecutionNotes = comment
return
}
}
if arm.mmap.HasTIMER {
if ok, comment := arm.state.timer.Write(addr, uint32(val)); ok {
arm.disasmExecutionNotes = comment
return
}
}
if arm.mmap.HasTIM2 {
if ok, comment := arm.state.timer2.Write(addr, uint32(val)); ok {
arm.disasmExecutionNotes = comment
return
}
}
if !arm.stackHasCollided {
arm.illegalAccess("Write 32bit", addr)
}
return
}
// ensure we're not accessing past the end of memory
if len(*mem) < 4 || addr >= uint32(len(*mem)-3) {
arm.illegalAccess("Write 32bit", addr)
return
}
arm.byteOrder.PutUint32((*mem)[addr:], val)
// (*mem)[addr] = uint8(val)
// (*mem)[addr+1] = uint8(val >> 8)
// (*mem)[addr+2] = uint8(val >> 16)
// (*mem)[addr+3] = uint8(val >> 24)
}