blob: 13270d28da9995b23dab7b3bb5818b283351371f (
plain) (
blame)
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
|
x86: 0.995
semantic: 0.974
architecture: 0.868
device: 0.758
graphic: 0.700
ppc: 0.665
debug: 0.650
performance: 0.552
vnc: 0.544
operating system: 0.543
i386: 0.538
assembly: 0.531
boot: 0.465
permissions: 0.443
kernel: 0.427
socket: 0.426
network: 0.393
PID: 0.358
register: 0.341
mistranslation: 0.299
risc-v: 0.293
files: 0.280
TCG: 0.255
arm: 0.252
alpha: 0.217
VMM: 0.216
KVM: 0.192
virtual: 0.176
peripherals: 0.166
user-level: 0.144
hypervisor: 0.126
--------------------
x86: 1.000
assembly: 0.992
semantic: 0.981
i386: 0.817
debug: 0.106
register: 0.039
files: 0.031
user-level: 0.025
risc-v: 0.019
virtual: 0.016
PID: 0.014
TCG: 0.013
VMM: 0.010
performance: 0.010
kernel: 0.008
architecture: 0.008
operating system: 0.007
alpha: 0.006
network: 0.006
device: 0.004
permissions: 0.004
boot: 0.004
hypervisor: 0.003
socket: 0.003
peripherals: 0.003
vnc: 0.002
graphic: 0.002
KVM: 0.002
ppc: 0.001
mistranslation: 0.001
arm: 0.000
x86 SSE/SSE2/SSE3 instruction semantic bugs with NaN
Description of problem
The result of SSE/SSE2/SSE3 instructions with NaN is different from the CPU. From Intel manual Volume 1 Appendix D.4.2.2, they defined the behavior of such instructions with NaN. But I think QEMU did not implement this semantic exactly because the byte result is different.
Steps to reproduce
Compile this code
void main() {
asm("mov rax, 0x000000007fffffff; push rax; mov rax, 0x00000000ffffffff; push rax; movdqu XMM1, [rsp];");
asm("mov rax, 0x2e711de7aa46af1a; push rax; mov rax, 0x7fffffff7fffffff; push rax; movdqu XMM2, [rsp];");
asm("addsubps xmm1, xmm2");
}
Execute and compare the result with the CPU. This problem happens with other SSE/SSE2/SSE3 instructions specified in the manual, Volume 1 Appendix D.4.2.2.
CPU xmm1[3] = 0xffffffff
QEMU xmm1[3] = 0x7fffffff
Additional information
This bug is discovered by research conducted by KAIST SoftSec.
|