>>>>> "JL" == Jack Lloyd <ll...@randombit.net> writes:
JL> It's also supported in (very very recent) GNU binutils.
The sample code Intel provided on that page compiled/assembled
correctly here, using binutils-2.21.
Noting again that the registers are ordered ax, cx, dx, bx, sp,
bp, si, di, then the opcodes are:
In 16-bit mode:
0F C7 F0 through 0F C7 F7
randomize 16-bit registers ax through di
In 32-bit mode:
66 0F C7 F0 through 66 0F C7 F7
randomize 16-bit registers ax through di
0F C7 F0 through 0F C7 F7
randomize 32-bit registers eax through edi
In 64-bit mode:
66 0F C7 F0 through 66 0F C7 F7
randomize 16-bit registers ax through di
0F C7 F0 through 0F C7 F7
randomize 32-bit registers eax through edi
41 0F C7 F0 through 41 0F C7 F7
randomize 32-bit registers r8d through r15d
48 0F C7 F0 through 48 0F C7 F7
randomize 64-bit registers rax through rdi
49 0F C7 F0 through 49 0F C7 F7
randomize 64-bit registers r8 through r15
I confirmed those via objdump(1)'s disassembly.
Note the use of prefix octet 0x66 to work on a 16-bit register when
in 32-bit or 64-bit modes and the use of 0x48|0x41 (aka 0x49) to access
the gp registers r8-r15 as 64-bit registers.
It'll be interesting to see what AMD does on this front.
-JimC
--
James Cloos <cl...@jhcloos.com> OpenPGP: 1024D/ED7DAEA6
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