[Webkit-unassigned] [Bug 131394] [FTL] Emit multibyte NOPs on X86-64

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=131394


Michael Saboff <msaboff at apple.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
 Attachment #228893|review?                     |review+
               Flag|                            |




--- Comment #4 from Michael Saboff <msaboff at apple.com>  2014-04-09 13:54:05 PST ---
(From update of attachment 228893)
View in context: https://bugs.webkit.org/attachment.cgi?id=228893&action=review

I don't think the variances from the Intel manual are a big deal, but why the slight variations?

r=me

> Source/JavaScriptCore/assembler/X86Assembler.h:2261
> +            {0x0f, 0x1f, 0x44, 0x00, 0x08},

The Intel Arch manual for SW Dev vol 2 shows a slightly different 5 byte opcode: x0f, 0x1f, 0x44, 0x00, -> 0x00 <-

> Source/JavaScriptCore/assembler/X86Assembler.h:2263
> +            {0x66, 0x0f, 0x1f, 0x44, 0x00, 0x08},

Same thing, the last byte in the Intel manual is 0x00.

> Source/JavaScriptCore/assembler/X86Assembler.h:2267
> +            {0x0f, 0x1f, 0x84, 0x00, 0x00, 0x02, 0x00, 0x00},

The intel manual shows the last 5 bytes as 0x00

> Source/JavaScriptCore/assembler/X86Assembler.h:2269
> +            {0x66, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x02, 0x00, 0x00},

The intel manual shows the last 5 bytes as 0x00

> Source/JavaScriptCore/assembler/X86Assembler.h:2271
> +            {0x66, 0x2e, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x02, 0x00, 0x00}

The intel manual shows the last 5 bytes as 0x00

-- 
Configure bugmail: https://bugs.webkit.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the assignee for the bug.