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1 | 386405f7 | bellard | \input texinfo @c -*- texinfo -*- |
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2 | 386405f7 | bellard | |
3 | 386405f7 | bellard | @settitle QEMU x86 Emulator Reference Documentation |
4 | 386405f7 | bellard | @titlepage |
5 | 386405f7 | bellard | @sp 7 |
6 | 386405f7 | bellard | @center @titlefont{QEMU x86 Emulator Reference Documentation} |
7 | 386405f7 | bellard | @sp 3 |
8 | 386405f7 | bellard | @end titlepage |
9 | 386405f7 | bellard | |
10 | 386405f7 | bellard | @chapter Introduction |
11 | 386405f7 | bellard | |
12 | 386405f7 | bellard | QEMU is an x86 processor emulator. Its purpose is to run x86 Linux |
13 | 386405f7 | bellard | processes on non-x86 Linux architectures such as PowerPC or ARM. By |
14 | 386405f7 | bellard | using dynamic translation it achieves a reasonnable speed while being |
15 | fd429f2f | bellard | easy to port on new host CPUs. Its main goal is to be able to launch the |
16 | fd429f2f | bellard | @code{Wine} Windows API emulator (@url{http://www.winehq.org}) on |
17 | fd429f2f | bellard | non-x86 CPUs. |
18 | 386405f7 | bellard | |
19 | 386405f7 | bellard | QEMU features: |
20 | 386405f7 | bellard | |
21 | 386405f7 | bellard | @itemize |
22 | 386405f7 | bellard | |
23 | 386405f7 | bellard | @item User space only x86 emulator. |
24 | 386405f7 | bellard | |
25 | fd429f2f | bellard | @item Currently ported on i386, PowerPC and S390. |
26 | 386405f7 | bellard | |
27 | fd429f2f | bellard | @item Using dynamic translation to native code for reasonnable speed. |
28 | 386405f7 | bellard | |
29 | 386405f7 | bellard | @item The virtual x86 CPU supports 16 bit and 32 bit addressing with segmentation. |
30 | fd429f2f | bellard | User space LDT and GDT are emulated. VM86 mode is also supported |
31 | fd429f2f | bellard | (experimental). |
32 | 386405f7 | bellard | |
33 | 386405f7 | bellard | @item Generic Linux system call converter, including most ioctls. |
34 | 386405f7 | bellard | |
35 | 386405f7 | bellard | @item clone() emulation using native CPU clone() to use Linux scheduler for threads. |
36 | 386405f7 | bellard | |
37 | 386405f7 | bellard | @item Accurate signal handling by remapping host signals to virtual x86 signals. |
38 | 386405f7 | bellard | |
39 | 1eb87257 | bellard | @item QEMU can emulate itself on x86 (experimental). |
40 | 1eb87257 | bellard | |
41 | 386405f7 | bellard | @item The virtual x86 CPU is a library (@code{libqemu}) which can be used |
42 | 386405f7 | bellard | in other projects. |
43 | 386405f7 | bellard | |
44 | 386405f7 | bellard | @item An extensive Linux x86 CPU test program is included @file{tests/test-i386}. |
45 | 386405f7 | bellard | It can be used to test other x86 virtual CPUs. |
46 | 386405f7 | bellard | |
47 | 386405f7 | bellard | @end itemize |
48 | 386405f7 | bellard | |
49 | 386405f7 | bellard | Current QEMU Limitations: |
50 | 386405f7 | bellard | |
51 | 386405f7 | bellard | @itemize |
52 | 386405f7 | bellard | |
53 | 386405f7 | bellard | @item Not all x86 exceptions are precise (yet). [Very few programs need that]. |
54 | 386405f7 | bellard | |
55 | 1eb87257 | bellard | @item No support for self-modifying code (yet). [Very few programs need that, a notable exception is QEMU itself !]. |
56 | 386405f7 | bellard | |
57 | 386405f7 | bellard | @item No SSE/MMX support (yet). |
58 | 386405f7 | bellard | |
59 | 386405f7 | bellard | @item No x86-64 support. |
60 | 386405f7 | bellard | |
61 | 386405f7 | bellard | @item Some Linux syscalls are missing. |
62 | 386405f7 | bellard | |
63 | 386405f7 | bellard | @item The x86 segment limits and access rights are not tested at every |
64 | 386405f7 | bellard | memory access (and will never be to have good performances). |
65 | 386405f7 | bellard | |
66 | 386405f7 | bellard | @item On non x86 host CPUs, @code{double}s are used instead of the non standard |
67 | 386405f7 | bellard | 10 byte @code{long double}s of x86 for floating point emulation to get |
68 | 386405f7 | bellard | maximum performances. |
69 | 386405f7 | bellard | |
70 | 386405f7 | bellard | @end itemize |
71 | 386405f7 | bellard | |
72 | 386405f7 | bellard | @chapter Invocation |
73 | 386405f7 | bellard | |
74 | d691f669 | bellard | @section Quick Start |
75 | d691f669 | bellard | |
76 | 386405f7 | bellard | In order to launch a Linux process, QEMU needs the process executable |
77 | d691f669 | bellard | itself and all the target (x86) dynamic libraries used by it. |
78 | d691f669 | bellard | |
79 | d691f669 | bellard | @itemize |
80 | 386405f7 | bellard | |
81 | d691f669 | bellard | @item On x86, you can just try to launch any process by using the native |
82 | d691f669 | bellard | libraries: |
83 | 386405f7 | bellard | |
84 | 386405f7 | bellard | @example |
85 | d691f669 | bellard | qemu -L / /bin/ls |
86 | 386405f7 | bellard | @end example |
87 | 386405f7 | bellard | |
88 | d691f669 | bellard | @code{-L /} tells that the x86 dynamic linker must be searched with a |
89 | d691f669 | bellard | @file{/} prefix. |
90 | 386405f7 | bellard | |
91 | 1eb87257 | bellard | @item Since QEMU is also a linux process, you can launch qemu with qemu: |
92 | 1eb87257 | bellard | |
93 | 1eb87257 | bellard | @example |
94 | 1eb87257 | bellard | qemu -L / qemu -L / /bin/ls |
95 | 1eb87257 | bellard | @end example |
96 | 386405f7 | bellard | |
97 | d691f669 | bellard | @item On non x86 CPUs, you need first to download at least an x86 glibc |
98 | 1eb87257 | bellard | (@file{qemu-XXX-i386-glibc21.tar.gz} on the QEMU web page). Ensure that |
99 | 644c433c | bellard | @code{LD_LIBRARY_PATH} is not set: |
100 | 644c433c | bellard | |
101 | 644c433c | bellard | @example |
102 | 644c433c | bellard | unset LD_LIBRARY_PATH |
103 | 644c433c | bellard | @end example |
104 | 644c433c | bellard | |
105 | 644c433c | bellard | Then you can launch the precompiled @file{ls} x86 executable: |
106 | 644c433c | bellard | |
107 | d691f669 | bellard | @example |
108 | 168485b7 | bellard | qemu /usr/local/qemu-i386/bin/ls-i386 |
109 | 168485b7 | bellard | @end example |
110 | 168485b7 | bellard | You can look at @file{/usr/local/qemu-i386/bin/qemu-conf.sh} so that |
111 | 168485b7 | bellard | QEMU is automatically launched by the Linux kernel when you try to |
112 | 168485b7 | bellard | launch x86 executables. It requires the @code{binfmt_misc} module in the |
113 | 168485b7 | bellard | Linux kernel. |
114 | 168485b7 | bellard | |
115 | 1eb87257 | bellard | @item The x86 version of QEMU is also included. You can try weird things such as: |
116 | 1eb87257 | bellard | @example |
117 | 1eb87257 | bellard | qemu /usr/local/qemu-i386/bin/qemu-i386 /usr/local/qemu-i386/bin/ls-i386 |
118 | 1eb87257 | bellard | @end example |
119 | 1eb87257 | bellard | |
120 | 168485b7 | bellard | @end itemize |
121 | 168485b7 | bellard | |
122 | 168485b7 | bellard | @section Wine launch (Currently only tested when emulating x86 on x86) |
123 | 168485b7 | bellard | |
124 | 168485b7 | bellard | @itemize |
125 | 168485b7 | bellard | |
126 | 168485b7 | bellard | @item Ensure that you have a working QEMU with the x86 glibc |
127 | 168485b7 | bellard | distribution (see previous section). In order to verify it, you must be |
128 | 168485b7 | bellard | able to do: |
129 | 168485b7 | bellard | |
130 | 168485b7 | bellard | @example |
131 | 168485b7 | bellard | qemu /usr/local/qemu-i386/bin/ls-i386 |
132 | 168485b7 | bellard | @end example |
133 | 168485b7 | bellard | |
134 | fd429f2f | bellard | @item Download the binary x86 Wine install |
135 | 1eb87257 | bellard | (@file{qemu-XXX-i386-wine.tar.gz} on the QEMU web page). |
136 | 168485b7 | bellard | |
137 | fd429f2f | bellard | @item Configure Wine on your account. Look at the provided script |
138 | 168485b7 | bellard | @file{/usr/local/qemu-i386/bin/wine-conf.sh}. Your previous |
139 | 168485b7 | bellard | @code{$@{HOME@}/.wine} directory is saved to @code{$@{HOME@}/.wine.org}. |
140 | 168485b7 | bellard | |
141 | 168485b7 | bellard | @item Then you can try the example @file{putty.exe}: |
142 | 168485b7 | bellard | |
143 | 168485b7 | bellard | @example |
144 | 168485b7 | bellard | qemu /usr/local/qemu-i386/wine/bin/wine /usr/local/qemu-i386/wine/c/Program\ Files/putty.exe |
145 | 386405f7 | bellard | @end example |
146 | d691f669 | bellard | |
147 | d691f669 | bellard | @end itemize |
148 | d691f669 | bellard | |
149 | d691f669 | bellard | @section Command line options |
150 | d691f669 | bellard | |
151 | d691f669 | bellard | @example |
152 | d691f669 | bellard | usage: qemu [-h] [-d] [-L path] [-s size] program [arguments...] |
153 | d691f669 | bellard | @end example |
154 | d691f669 | bellard | |
155 | d691f669 | bellard | @table @samp |
156 | d691f669 | bellard | @item -h |
157 | d691f669 | bellard | Print the help |
158 | d691f669 | bellard | @item -d |
159 | d691f669 | bellard | Activate log (logfile=/tmp/qemu.log) |
160 | d691f669 | bellard | @item -L path |
161 | d691f669 | bellard | Set the x86 elf interpreter prefix (default=/usr/local/qemu-i386) |
162 | d691f669 | bellard | @item -s size |
163 | d691f669 | bellard | Set the x86 stack size in bytes (default=524288) |
164 | d691f669 | bellard | @end table |
165 | 386405f7 | bellard | |
166 | 386405f7 | bellard | @chapter QEMU Internals |
167 | 386405f7 | bellard | |
168 | 386405f7 | bellard | @section QEMU compared to other emulators |
169 | 386405f7 | bellard | |
170 | 386405f7 | bellard | Unlike bochs [3], QEMU emulates only a user space x86 CPU. It means that |
171 | 386405f7 | bellard | you cannot launch an operating system with it. The benefit is that it is |
172 | 386405f7 | bellard | simpler and faster due to the fact that some of the low level CPU state |
173 | 386405f7 | bellard | can be ignored (in particular, no virtual memory needs to be emulated). |
174 | 386405f7 | bellard | |
175 | 386405f7 | bellard | Like Valgrind [2], QEMU does user space emulation and dynamic |
176 | 386405f7 | bellard | translation. Valgrind is mainly a memory debugger while QEMU has no |
177 | 386405f7 | bellard | support for it (QEMU could be used to detect out of bound memory accesses |
178 | 386405f7 | bellard | as Valgrind, but it has no support to track uninitialised data as |
179 | 386405f7 | bellard | Valgrind does). Valgrind dynamic translator generates better code than |
180 | 386405f7 | bellard | QEMU (in particular it does register allocation) but it is closely tied |
181 | 386405f7 | bellard | to an x86 host. |
182 | 386405f7 | bellard | |
183 | 386405f7 | bellard | EM86 [4] is the closest project to QEMU (and QEMU still uses some of its |
184 | 386405f7 | bellard | code, in particular the ELF file loader). EM86 was limited to an alpha |
185 | 386405f7 | bellard | host and used a proprietary and slow interpreter (the interpreter part |
186 | 386405f7 | bellard | of the FX!32 Digital Win32 code translator [5]). |
187 | 386405f7 | bellard | |
188 | fd429f2f | bellard | TWIN [6] is a Windows API emulator like Wine. It is less accurate than |
189 | fd429f2f | bellard | Wine but includes a protected mode x86 interpreter to launch x86 Windows |
190 | fd429f2f | bellard | executables. Such an approach as greater potential because most of the |
191 | fd429f2f | bellard | Windows API is executed natively but it is far more difficult to develop |
192 | fd429f2f | bellard | because all the data structures and function parameters exchanged |
193 | fd429f2f | bellard | between the API and the x86 code must be converted. |
194 | fd429f2f | bellard | |
195 | 386405f7 | bellard | @section Portable dynamic translation |
196 | 386405f7 | bellard | |
197 | 386405f7 | bellard | QEMU is a dynamic translator. When it first encounters a piece of code, |
198 | 386405f7 | bellard | it converts it to the host instruction set. Usually dynamic translators |
199 | 386405f7 | bellard | are very complicated and highly CPU dependant. QEMU uses some tricks |
200 | 386405f7 | bellard | which make it relatively easily portable and simple while achieving good |
201 | 386405f7 | bellard | performances. |
202 | 386405f7 | bellard | |
203 | 386405f7 | bellard | The basic idea is to split every x86 instruction into fewer simpler |
204 | 386405f7 | bellard | instructions. Each simple instruction is implemented by a piece of C |
205 | 386405f7 | bellard | code (see @file{op-i386.c}). Then a compile time tool (@file{dyngen}) |
206 | 386405f7 | bellard | takes the corresponding object file (@file{op-i386.o}) to generate a |
207 | 386405f7 | bellard | dynamic code generator which concatenates the simple instructions to |
208 | 386405f7 | bellard | build a function (see @file{op-i386.h:dyngen_code()}). |
209 | 386405f7 | bellard | |
210 | 386405f7 | bellard | In essence, the process is similar to [1], but more work is done at |
211 | 386405f7 | bellard | compile time. |
212 | 386405f7 | bellard | |
213 | 386405f7 | bellard | A key idea to get optimal performances is that constant parameters can |
214 | 386405f7 | bellard | be passed to the simple operations. For that purpose, dummy ELF |
215 | 386405f7 | bellard | relocations are generated with gcc for each constant parameter. Then, |
216 | 386405f7 | bellard | the tool (@file{dyngen}) can locate the relocations and generate the |
217 | 386405f7 | bellard | appriopriate C code to resolve them when building the dynamic code. |
218 | 386405f7 | bellard | |
219 | 386405f7 | bellard | That way, QEMU is no more difficult to port than a dynamic linker. |
220 | 386405f7 | bellard | |
221 | 386405f7 | bellard | To go even faster, GCC static register variables are used to keep the |
222 | 386405f7 | bellard | state of the virtual CPU. |
223 | 386405f7 | bellard | |
224 | 386405f7 | bellard | @section Register allocation |
225 | 386405f7 | bellard | |
226 | 386405f7 | bellard | Since QEMU uses fixed simple instructions, no efficient register |
227 | 386405f7 | bellard | allocation can be done. However, because RISC CPUs have a lot of |
228 | 386405f7 | bellard | register, most of the virtual CPU state can be put in registers without |
229 | 386405f7 | bellard | doing complicated register allocation. |
230 | 386405f7 | bellard | |
231 | 386405f7 | bellard | @section Condition code optimisations |
232 | 386405f7 | bellard | |
233 | 386405f7 | bellard | Good CPU condition codes emulation (@code{EFLAGS} register on x86) is a |
234 | 386405f7 | bellard | critical point to get good performances. QEMU uses lazy condition code |
235 | 386405f7 | bellard | evaluation: instead of computing the condition codes after each x86 |
236 | fd429f2f | bellard | instruction, it just stores one operand (called @code{CC_SRC}), the |
237 | 386405f7 | bellard | result (called @code{CC_DST}) and the type of operation (called |
238 | 386405f7 | bellard | @code{CC_OP}). |
239 | 386405f7 | bellard | |
240 | 386405f7 | bellard | @code{CC_OP} is almost never explicitely set in the generated code |
241 | 386405f7 | bellard | because it is known at translation time. |
242 | 386405f7 | bellard | |
243 | 386405f7 | bellard | In order to increase performances, a backward pass is performed on the |
244 | 386405f7 | bellard | generated simple instructions (see |
245 | 386405f7 | bellard | @code{translate-i386.c:optimize_flags()}). When it can be proved that |
246 | 386405f7 | bellard | the condition codes are not needed by the next instructions, no |
247 | 386405f7 | bellard | condition codes are computed at all. |
248 | 386405f7 | bellard | |
249 | fd429f2f | bellard | @section CPU state optimisations |
250 | 386405f7 | bellard | |
251 | 386405f7 | bellard | The x86 CPU has many internal states which change the way it evaluates |
252 | 386405f7 | bellard | instructions. In order to achieve a good speed, the translation phase |
253 | 386405f7 | bellard | considers that some state information of the virtual x86 CPU cannot |
254 | 386405f7 | bellard | change in it. For example, if the SS, DS and ES segments have a zero |
255 | 386405f7 | bellard | base, then the translator does not even generate an addition for the |
256 | 386405f7 | bellard | segment base. |
257 | 386405f7 | bellard | |
258 | 386405f7 | bellard | [The FPU stack pointer register is not handled that way yet]. |
259 | 386405f7 | bellard | |
260 | 386405f7 | bellard | @section Translation cache |
261 | 386405f7 | bellard | |
262 | 386405f7 | bellard | A 2MByte cache holds the most recently used translations. For |
263 | 386405f7 | bellard | simplicity, it is completely flushed when it is full. A translation unit |
264 | 386405f7 | bellard | contains just a single basic block (a block of x86 instructions |
265 | 386405f7 | bellard | terminated by a jump or by a virtual CPU state change which the |
266 | 386405f7 | bellard | translator cannot deduce statically). |
267 | 386405f7 | bellard | |
268 | 386405f7 | bellard | [Currently, the translated code is not patched if it jumps to another |
269 | 386405f7 | bellard | translated code]. |
270 | 386405f7 | bellard | |
271 | 386405f7 | bellard | @section Exception support |
272 | 386405f7 | bellard | |
273 | 386405f7 | bellard | longjmp() is used when an exception such as division by zero is |
274 | 386405f7 | bellard | encountered. The host SIGSEGV and SIGBUS signal handlers are used to get |
275 | 386405f7 | bellard | invalid memory accesses. |
276 | 386405f7 | bellard | |
277 | 386405f7 | bellard | [Currently, the virtual CPU cannot retrieve the exact CPU state in some |
278 | 386405f7 | bellard | exceptions, although it could except for the @code{EFLAGS} register]. |
279 | 386405f7 | bellard | |
280 | 386405f7 | bellard | @section Linux system call translation |
281 | 386405f7 | bellard | |
282 | 386405f7 | bellard | QEMU includes a generic system call translator for Linux. It means that |
283 | 386405f7 | bellard | the parameters of the system calls can be converted to fix the |
284 | 386405f7 | bellard | endianness and 32/64 bit issues. The IOCTLs are converted with a generic |
285 | 386405f7 | bellard | type description system (see @file{ioctls.h} and @file{thunk.c}). |
286 | 386405f7 | bellard | |
287 | 386405f7 | bellard | @section Linux signals |
288 | 386405f7 | bellard | |
289 | 386405f7 | bellard | Normal and real-time signals are queued along with their information |
290 | 386405f7 | bellard | (@code{siginfo_t}) as it is done in the Linux kernel. Then an interrupt |
291 | 386405f7 | bellard | request is done to the virtual CPU. When it is interrupted, one queued |
292 | 386405f7 | bellard | signal is handled by generating a stack frame in the virtual CPU as the |
293 | 386405f7 | bellard | Linux kernel does. The @code{sigreturn()} system call is emulated to return |
294 | 386405f7 | bellard | from the virtual signal handler. |
295 | 386405f7 | bellard | |
296 | 386405f7 | bellard | Some signals (such as SIGALRM) directly come from the host. Other |
297 | 386405f7 | bellard | signals are synthetized from the virtual CPU exceptions such as SIGFPE |
298 | 386405f7 | bellard | when a division by zero is done (see @code{main.c:cpu_loop()}). |
299 | 386405f7 | bellard | |
300 | 386405f7 | bellard | The blocked signal mask is still handled by the host Linux kernel so |
301 | 386405f7 | bellard | that most signal system calls can be redirected directly to the host |
302 | 386405f7 | bellard | Linux kernel. Only the @code{sigaction()} and @code{sigreturn()} system |
303 | 386405f7 | bellard | calls need to be fully emulated (see @file{signal.c}). |
304 | 386405f7 | bellard | |
305 | 386405f7 | bellard | @section clone() system call and threads |
306 | 386405f7 | bellard | |
307 | 386405f7 | bellard | The Linux clone() system call is usually used to create a thread. QEMU |
308 | 386405f7 | bellard | uses the host clone() system call so that real host threads are created |
309 | 386405f7 | bellard | for each emulated thread. One virtual CPU instance is created for each |
310 | 386405f7 | bellard | thread. |
311 | 386405f7 | bellard | |
312 | 386405f7 | bellard | The virtual x86 CPU atomic operations are emulated with a global lock so |
313 | 386405f7 | bellard | that their semantic is preserved. |
314 | 386405f7 | bellard | |
315 | 1eb87257 | bellard | @section Self-virtualization |
316 | 1eb87257 | bellard | |
317 | 1eb87257 | bellard | QEMU was conceived so that ultimately it can emulate itself. Althought |
318 | 1eb87257 | bellard | it is not very useful, it is an important test to show the power of the |
319 | 1eb87257 | bellard | emulator. |
320 | 1eb87257 | bellard | |
321 | 1eb87257 | bellard | Achieving self-virtualization is not easy because there may be address |
322 | 6cd9f35b | bellard | space conflicts. QEMU solves this problem by being an executable ELF |
323 | 6cd9f35b | bellard | shared object as the ld-linux.so ELF interpreter. That way, it can be |
324 | 6cd9f35b | bellard | relocated at load time. |
325 | 1eb87257 | bellard | |
326 | 6cd9f35b | bellard | Since self-modifying code is not supported yet, QEMU cannot emulate |
327 | 6cd9f35b | bellard | itself in case of translation cache flush. This limitation will be |
328 | 6cd9f35b | bellard | suppressed soon. |
329 | 1eb87257 | bellard | |
330 | 386405f7 | bellard | @section Bibliography |
331 | 386405f7 | bellard | |
332 | 386405f7 | bellard | @table @asis |
333 | 386405f7 | bellard | |
334 | 386405f7 | bellard | @item [1] |
335 | 386405f7 | bellard | @url{http://citeseer.nj.nec.com/piumarta98optimizing.html}, Optimizing |
336 | 386405f7 | bellard | direct threaded code by selective inlining (1998) by Ian Piumarta, Fabio |
337 | 386405f7 | bellard | Riccardi. |
338 | 386405f7 | bellard | |
339 | 386405f7 | bellard | @item [2] |
340 | 386405f7 | bellard | @url{http://developer.kde.org/~sewardj/}, Valgrind, an open-source |
341 | 386405f7 | bellard | memory debugger for x86-GNU/Linux, by Julian Seward. |
342 | 386405f7 | bellard | |
343 | 386405f7 | bellard | @item [3] |
344 | 386405f7 | bellard | @url{http://bochs.sourceforge.net/}, the Bochs IA-32 Emulator Project, |
345 | 386405f7 | bellard | by Kevin Lawton et al. |
346 | 386405f7 | bellard | |
347 | 386405f7 | bellard | @item [4] |
348 | 386405f7 | bellard | @url{http://www.cs.rose-hulman.edu/~donaldlf/em86/index.html}, the EM86 |
349 | 386405f7 | bellard | x86 emulator on Alpha-Linux. |
350 | 386405f7 | bellard | |
351 | 386405f7 | bellard | @item [5] |
352 | 386405f7 | bellard | @url{http://www.usenix.org/publications/library/proceedings/usenix-nt97/full_papers/chernoff/chernoff.pdf}, |
353 | 386405f7 | bellard | DIGITAL FX!32: Running 32-Bit x86 Applications on Alpha NT, by Anton |
354 | 386405f7 | bellard | Chernoff and Ray Hookway. |
355 | 386405f7 | bellard | |
356 | fd429f2f | bellard | @item [6] |
357 | fd429f2f | bellard | @url{http://www.willows.com/}, Windows API library emulation from |
358 | fd429f2f | bellard | Willows Software. |
359 | fd429f2f | bellard | |
360 | 386405f7 | bellard | @end table |
361 | 386405f7 | bellard | |
362 | 386405f7 | bellard | @chapter Regression Tests |
363 | 386405f7 | bellard | |
364 | 386405f7 | bellard | In the directory @file{tests/}, various interesting x86 testing programs |
365 | 386405f7 | bellard | are available. There are used for regression testing. |
366 | 386405f7 | bellard | |
367 | 386405f7 | bellard | @section @file{hello} |
368 | 386405f7 | bellard | |
369 | 386405f7 | bellard | Very simple statically linked x86 program, just to test QEMU during a |
370 | 386405f7 | bellard | port to a new host CPU. |
371 | 386405f7 | bellard | |
372 | 386405f7 | bellard | @section @file{test-i386} |
373 | 386405f7 | bellard | |
374 | 386405f7 | bellard | This program executes most of the 16 bit and 32 bit x86 instructions and |
375 | 386405f7 | bellard | generates a text output. It can be compared with the output obtained with |
376 | 386405f7 | bellard | a real CPU or another emulator. The target @code{make test} runs this |
377 | 386405f7 | bellard | program and a @code{diff} on the generated output. |
378 | 386405f7 | bellard | |
379 | 386405f7 | bellard | The Linux system call @code{modify_ldt()} is used to create x86 selectors |
380 | 386405f7 | bellard | to test some 16 bit addressing and 32 bit with segmentation cases. |
381 | 386405f7 | bellard | |
382 | 386405f7 | bellard | @section @file{testsig} |
383 | 386405f7 | bellard | |
384 | 386405f7 | bellard | This program tests various signal cases, including SIGFPE, SIGSEGV and |
385 | 386405f7 | bellard | SIGILL. |
386 | 386405f7 | bellard | |
387 | 386405f7 | bellard | @section @file{testclone} |
388 | 386405f7 | bellard | |
389 | 386405f7 | bellard | Tests the @code{clone()} system call (basic test). |
390 | 386405f7 | bellard | |
391 | 386405f7 | bellard | @section @file{testthread} |
392 | 386405f7 | bellard | |
393 | 386405f7 | bellard | Tests the glibc threads (more complicated than @code{clone()} because signals |
394 | 386405f7 | bellard | are also used). |
395 | 386405f7 | bellard | |
396 | 386405f7 | bellard | @section @file{sha1} |
397 | 386405f7 | bellard | |
398 | 386405f7 | bellard | It is a simple benchmark. Care must be taken to interpret the results |
399 | 386405f7 | bellard | because it mostly tests the ability of the virtual CPU to optimize the |
400 | 386405f7 | bellard | @code{rol} x86 instruction and the condition code computations. |
401 | 386405f7 | bellard | |
402 | fd429f2f | bellard | @section @file{runcom} |
403 | fd429f2f | bellard | |
404 | fd429f2f | bellard | A very simple MSDOS emulator to test the Linux vm86() system call |
405 | fd429f2f | bellard | emulation. The excellent 54 byte @file{pi_10.com} PI number calculator |
406 | fd429f2f | bellard | can be launched with it. @file{pi_10.com} was written by Bertram |
407 | fd429f2f | bellard | Felgenhauer (more information at @url{http://www.boo.net/~jasonp/pipage.html}). |