Rosetta sets RDTSCP's ECX to its constant TSC_AUX, 0xAAAAAAAB, which is
not a processor index. --to-rosetta already makes RDPID return processor
0 for the same reason, so code reading the processor through RDTSCP saw
a different value from code reading it through RDPID.
--to-rosetta now moves RDTSCP into an optional stub that runs the
instruction unchanged and then loads 0 into ECX with a MOV, which
leaves the counter in EDX:EAX and the flags as they were. A site with no
movable instruction after it for the jump is kept, as for RDPID. The
Intel target and a plain relink are unchanged.
66 E8, 66 E9 and 66 0F 80-8F without REX.W take a 16-bit displacement on
AMD processors, the console included. Every near relative branch with that
prefix truncates its target to 16 bits, so the decoder reports no branch
target for it and stubs refuse to move it.
Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_016TFMtUC4L4wMS4eeEqaNSR
The Rosetta conversion limits were measured on an M1 running macOS 15.3.1
and an M5 Max. A survey on an M5 running macOS 26.4 executes ANDN, RDRAND,
the rest of BMI1 and BMI2, LZCNT, PREFETCHW, CLFLUSHOPT, AVX, AVX2, FMA,
F16C and MOVBE while CPUID reports none of them, and raises an illegal
instruction for RDSEED, CLWB, RDPID, ADCX and ADOX.
AnyPS5 exports some libkernel functions, such as __error, from
libc.prx, which libkernel.prx links. On Linux they resolve through that
dependency. On Windows, the import stubs search only the listed
modules, and libc.prx was listed only when libSceLibcInternal.prx was
needed. A PS4 homebrew that needs libkernel.prx but no C library (the
OpenOrbis graphics sample) failed with "unresolved ELF import
9BcDykPmo1I". libc.prx is now also listed when libkernel.prx is needed.
PS5 executables need libSceLibcInternal.prx and convert unchanged.
OpenOrbis modules keep read-only data after their code, as executables
do. The syscall scan of sce_module modules decoded it, and the module of
the OpenOrbis library sample (libExample.prx) failed with "Forbidden
syscall instruction". For modules with a PT_SCE_DYNLIBDATA segment, the
scan now stops at the end of the PLT after the last unwind function,
found by FindSceCodeEnd as for executables.
The same modules begin their executable segment with the
/libexec/ld-elf.so.1 string but have no PT_INTERP header, so code
analysis decoded the string and failed with "Unsupported Windows guest
TLS instruction (bytes: 64 2d 65 6c 66 2e)", which is the text "d-elf.".
When no PT_INTERP header covers the start of a PS4 code segment, code
analysis now starts after that exact string.
DecodeInstruction returned before reading the ModRM of FF /3 and FF /5,
so a far CALL or JMP through a RIP-relative pointer had no RIP-relative
displacement. A stub that moved such a JMP copied the displacement
without relocating it.
The decoder was compared with iced-x86 (AMD decoding) over 3.99 million
encodings: every opcode of the legacy, 0F, 0F38 and 0F3A maps under 34
prefix combinations and the VEX 0F, 0F38 and 0F3A maps, each with 48
ModRM forms. Apart from this, it agrees on length, RIP-relative offset,
control flow kind and branch target for every valid Zen 2 instruction
except near branches with a 66 prefix, recorded as technical debt, and
kernel-only returns, which it treats as sequential.
Add the comparison's metadata as cases: one RIP-relative encoding per
opcode, map and immediate size, every FF /r form, and the branch forms
with their flow kind and target. The existing cases check lengths only;
a loop or jrcxz decoded as an unconditional jump passed the whole suite.
With --trace-imports the entry stub resolves TraceImport_nid_no_patch
in libc.prx and passes each function import through it before writing
the slot: every PLT slot, and a GOT slot only when the original symbol
is a function, so data imports such as __stdoutp keep their address.
Without the option the output is unchanged.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
Karim Masmoudi