capstone-engine
Incorrect aarch64 umov decoding
Work environment
| Questions | Answers |
|---|---|
| OS/arch/bits | Ubuntu 20.04, 64 bit |
| Architecture | armv8 |
| Source of Capstone | git clone |
| Version/git commit | v5.0.1, 097c04d9413c59a58b00d4d1c8d5dc0ac158ffaa |
Instruction bytes giving faulty results
0x43,0x3c,0x1c,0x0e
Expected results
It should be:
umov w3, v2.S[3]
Steps to get the wrong result
./cstool -d arm64 0x43,0x3c,0x1c,0x0e 0x1000
1000 43 3c 1c 0e mov w3, v2.s[3]
ID: 488 (mov)
op_count: 2
operands[0].type: REG = w3
operands[0].access: WRITE
operands[1].type: REG = v2
operands[1].access: WRITE
Vector Arrangement Specifier: 0xb
Vector Index: 3
Registers modified: w3 v2
Groups: neon
Additional Logs, screenshots, source code, configuration dump, ...
According to official arm doc it's really alias on UMOV instruction, that's why ID: 488 (mov) is incorrect and leads to errors while using capstone as a library
I would advice to use the next branch for AArch64. It is better in every dimension. This one is fixed there in more then one way (note the incorrect access of operands in the example of yours):
On next branch:
./cstool -d aarch64 0x43,0x3c,0x1c,0x0e 0x1000
1000 43 3c 1c 0e mov w3, v2.s[3]
ID: 1285 (umov)
Is alias: 1429 (mov) with ALIAS operand set
op_count: 2
operands[0].type: REG = w3
operands[0].access: WRITE
operands[1].type: REG = q2 (vreg)
operands[1].access: READ
Vector Arrangement Specifier: 0x20
Vector Index: 3
Registers read: q2
Registers modified: w3
Groups: HasNEON
Added it of course to the v5.0.2 milestone nonetheless.
If you want to use the next branch I advice to wait for https://github.com/capstone-engine/capstone/pull/2298 and https://github.com/capstone-engine/capstone/pull/2321 to be merged.
Sorry, but next branch totally breaks API
could it be possible to change the major version of the project to make life easier
could it be possible to change the major version of the project to make life easier
The next branch is the development branch and will be released as v6 (planned in September).
If you need to check the "next" version number in source, you can use the CS_NEXT_VERSION macro.
Sorry, but next branch totally breaks API
Have you already tried to use https://github.com/capstone-engine/capstone/pull/2321?
This should fix the rename problem from ARM64 to AArch64.
If you don't want to fiddle with merging PRs locally please stand by until @aquynh and @kabeor reviewed and merged it.
Also, as a general overview and justifications for API changes see the release guide: https://github.com/capstone-engine/capstone/blob/next/docs/cs_v6_release_guide.md
When it comes to new or removed instructions, please note that they changed unfortunately in the past quite often as well. This was because Capstone didn't do a clear distinction between instruction alias and real instructions. This is now fixed. But this is as well explained in the release guide.