tremalrik
tremalrik
According to the Intel SDM (volume 1, section 18.3.1), when CET is enabled, the prefix byte 3Eh should act as a "notrack" prefix for indirect JMP/CALL instructions. However, XED doesn't...
Taking a look at the `endbr64` instruction, its encoding is listed in the SDM as `F3 0F 1E FA`. From what I can find, most discussion around this instruction seems...
Doing a bunch of tests with Zydis, I've identified instructions that it doesn't decode properly: - RDSSPD in 64-bit mode. "ZydisInfo -64 f3 0f 1e c8" returns "nop eax,ecx" and...
According to the KNC instruction set reference manual ( https://community.intel.com/legacyfs/online/drupal_files/forum/278102/327364001en.pdf , sections 3.4 and 6.1 ), the VEX prefix for the KNC-specific instructions is required to have the L-bit (bit...
The VIA C3 processor features an instruction referred to as `ALTINST` with an encoding of `0F 3F`, that Zydis currently doesn't recognize. This instruction exists as an officially documented instruction...
Having gotten hold of a box with a Zhaoxin KX-6580 CPU (Chinese x86 cpu vendor; formed as a joint venture of VIA and Shanghai; their designs are mostly a continuation...
There are a number of undefined x86 instruction encodings that have been used to provide syscall-like functionality through the #UD (int 6) invalid opcode exception handler. The ones I've been...
Intel has fairly recently posted a draft specification ( https://software.intel.com/content/dam/develop/external/us/en/documents-tps/346446-flexible-return-and-event-delivery.pdf ) for its planned FRED ("Flexible Return and Event Delivery") x86 ISA extension. This specification lists three new instructions: *...
There are a few instructions where Zydis/ZydisInfo reports one of the instruction operands as a register operand, but where I believe it would be more accurate to report the operand...
Doing further digging, I've found a handful of instructions that have been supported by only a limited number of old Intel x86 processors and that Zydis doesn't recognize: - MOV...