[webkit-reviews] review granted: [Bug 131394] [FTL] Emit multibyte NOPs on X86-64 : [Attachment 228893] Patch

bugzilla-daemon at webkit.org bugzilla-daemon at webkit.org
Wed Apr 9 13:53:44 PDT 2014


Michael Saboff <msaboff at apple.com> has granted Juergen Ributzka
<juergen at apple.com>'s request for review:
Bug 131394: [FTL] Emit multibyte NOPs on X86-64
https://bugs.webkit.org/show_bug.cgi?id=131394

Attachment 228893: Patch
https://bugs.webkit.org/attachment.cgi?id=228893&action=review

------- Additional Comments from Michael Saboff <msaboff at apple.com>
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


More information about the webkit-reviews mailing list