blob: 70dc47253e502b442777fa67293ccd1cadbf18c1 (
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
|
graphic: 0.911
instruction: 0.860
semantic: 0.851
device: 0.824
mistranslation: 0.777
other: 0.760
socket: 0.746
vnc: 0.726
network: 0.692
assembly: 0.664
boot: 0.553
KVM: 0.417
SPARC32-bit SDIV of negative divisor gives wrong result
Description of problem:
SDIV of negative divisor gives wrong result because of typo in helper_sdiv(). This is true for QEMU 9.0.0 and earlier.
Place -1 in the Y register and -128 in another reg, then -120 in another register and do SDIV into a result register, instead of the proper value of 1 for the result, the incorrect value of 0 is produced.
There is a typo in target/sparc/helper.c that causes the divisor to be consider unsigned, this patch fixes it:
\*\*\* helper.c.ori Tue Apr 23 16:23:45 2024 --- helper.c Mon Apr 29 20:14:07 2024
---
\*\*\* 121,127 \*\*\*\* return (uint32_t)(b32 \< 0 ? INT32_MAX : INT32_MIN) | (-1ull \<\< 32); }
! a64 /= b; r = a64; if (unlikely(r != a64)) { return (uint32_t)(a64 \< 0 ? INT32_MIN : INT32_MAX) | (-1ull \<\< 32); --- 121,127 ---- return (uint32_t)(b32 \< 0 ? INT32_MAX : INT32_MIN) | (-1ull \<\< 32); }
! a64 /= b32; r = a64; if (unlikely(r != a64)) { return (uint32_t)(a64 \< 0 ? INT32_MIN : INT32_MAX) | (-1ull \<\< 32);
|