Re: x86/x64 JIT assembler for C++

Hi Phil,

>I notice that for code alignment you use a sequence of
>individual nops. Might the following be useful?

Thank you for your advice.
I had tried to add the optimized nop when I was implementing align()
before.

But the best way to optimize nop is different according to type of
CPU,
then detection of the type is necessary.

Though I can write the code, I don't think the function should be in
xbyak.h.
I intend to make xbyak_util.h(for example) and add the function in the
header.

cf.
 "Software Optimization Guide for AMD64 Processors"
http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/25112.PDF
4.12 Code Padding with Operand-Size Override and NOP

90
66 90
66 66 90
66 66 66 90
66 66 90 66 90

"Intel 64 and IA-32 Architectures Optimization Reference Manual"
3.5.1.8 Using NOPs
http://download.intel.com/design/PentiumII/manuals/24512701.pdf

90                ; xchg, eax, eax
89 C0             ; mov eax, eax
8D 40 00          ; lea eax, [eax + 0x00]
90 8D 40 00       ; nop / lea eax, [eax + 0x00]
....

---
herumi