Code review - Issue 299230043: i#1942 vpbroadcast: Support vpbroadcastb/w/d/q AVX2 instructionshttps://codereview.appspot.com/2016-06-12T21:13:39+00:00rietveld
Message from unknown
2016-06-03T05:27:21+00:00rocallahanurn:md5:36434195d3b65f20038916198dd40fbc
Message from rocallahan@gmail.com
2016-06-03T05:27:25+00:00rocallahanurn:md5:12a8bc896abf9d78d0ad91ef313e527d
Message from rocallahan@gmail.com
2016-06-03T05:29:58+00:00rocallahanurn:md5:fcf3d318d5beaddaf7ebc70ada5ee32d
I admit I wasn't completely sure what I was doing here. In particular I couldn't figure out whether I should use vex_extensions or third_byte_38 for these instructions. This code seems to decode the instructions correctly at least.
Message from bruening@google.com
2016-06-12T21:00:58+00:00brueningurn:md5:25c89cbcc8c49328f2da1acb16f40983
On 2016/06/03 05:29:58, rocallahan wrote:
> I admit I wasn't completely sure what I was doing here. In particular I couldn't
> figure out whether I should use vex_extensions or third_byte_38 for these
> instructions. This code seems to decode the instructions correctly at least.
They can just live in the third_byte_38 array: vex_extensions is just adding overhead unnecessarily in this case. Since I'm committing it I will make that change. The rest looks good. Thanks for the patch.
Message from bruening@google.com
2016-06-12T21:01:06+00:00brueningurn:md5:0820279d8a2f8bcc0ea61effeabecdbe
https://codereview.appspot.com/299230043/diff/1/core/arch/x86/decode_table.c
File core/arch/x86/decode_table.c (right):
https://codereview.appspot.com/299230043/diff/1/core/arch/x86/decode_table.c#newcode4542
core/arch/x86/decode_table.c:4542: {OP_vpbroadcastb, 0x66387818, "vpbroadcastb", Vx, xx, Wb_dq, xx, xx, mrm|vex|reqp, x, END_LIST},
There is no reason to indirect these to the vex_ext table, as there is no non-vex-encoded instruction to distinguish from. The "vex" flag already indicates that this is illegal without a vex encoding.
Message from rocallahan@gmail.com
2016-06-12T21:13:39+00:00rocallahanurn:md5:6d38581560bf211787e937b94c71d021
Great, thanks!