Hi Madhu!
Thank you for your reply.
>> Could you please confirm whether this is the document you are referring to? https://cdrdv2.intel.com/v1/dl/getContent/671200
Yes indeed. That's the one.
>> Could you please elaborate on what do you mean by the “parsable” pseudo code?
I think about how to uplift the x86 instructions to the intermediate language RZIL. One way to uplift so many instructions would be to take the behavior of each single instruction (written in something C like) and compile it into the intermediate language.
To make this possible the compiler/parser would need a mostly well defined language the instruction behavior is written in.
Here an example:
The PUSHA instruction behavior in the manual looks like this:
IF 64-bit Mode
THEN #UD
FI;
IF OperandSize = 32 (* PUSHAD instruction *)
THEN
Temp := (ESP);
Push(EAX);
Push(ECX);
Push(EDX);
Push(EBX);
Push(Temp);
Push(EBP);
Push(ESI);
Push(EDI);
ELSE (* OperandSize = 16, PUSHA instruction *)
Temp := (SP);
Push(AX);
Push(CX);
Push(DX);
...
Syntax like "IF 64-bit Mode" makes it really hard to parse and compile this instruction behavior into an intermediate language.
Another example would be the MASKMOVDQU instruction:
The behavior in the manual is:
IF (MASK[7] = 1)
THEN DEST[DI/EDI] := SRC[7:0] ELSE (* Memory location unchanged *); FI;
IF (MASK[15] = 1)
THEN DEST[DI/EDI +1] := SRC[15:8] ELSE (* Memory location unchanged *); FI;
(* Repeat operation for 3rd through 14th bytes in source operand *)
IF (MASK[127] = 1)
THEN DEST[DI/EDI +15] := SRC[127:120] ELSE (* Memory location unchanged *); FI;
The corresponding intrinsic "void _mm_maskmoveu_si128(__m128i d, __m128i n, char * p)" is:
FOR j := 0 to 15
i := j*8
IF mask[i+7]
MEM[mem_addr+i+7:mem_addr+i] := a[i+7:i]
FI
ENDFOR
The latter one could be easily parsed and compiled into the intermediate language. The former not so easily.
