[SOLVED] Unrecognized Opcodes
lazarus / 64-FPC development

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MathMan · 2014-07-31 08:08

Hi all,

I am using Lazarus 1.2.4 with FPC 2.6.4 under Windows 7/64bit on a
Core i5 430M @2,27GHz.

There are the very nifty ADCX / ADOX opcodes which the internal
assmbler does not seem to know.

Code: [Select]  @Loop1:

    align   4
    mov     RAX, qword ptr [RSI+8*RDX];   // Get next limb
    adcx    RAX, qword ptr [RBX+8*RDX];   // Add and only affect CF
    mov     qword ptr [RDI+8*RDX], RAX;   // Store the result

The above throws

Code: [Select]main.pas(480,5) Error: Unrecognized opcode ADCX

Is anybody around here who can comment on the following

* is it planned to integrate ADCX / ADOX opcode support to the
internal assembler
* as I am aware that potentially nobody beside me wants to use these
opcodes how are the chances if I raise a corresponding feature request
for FPC

Thanks in advance

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BigChimp · 2014-07-31 08:12

Regarding the seoncd issue: if these are valid opcodes, IMO there is
no reason NOT to raise the bugtracker issue.

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MathMan · 2014-07-31 08:17

Quote from: BigChimp on July 31, 2014, 10:12:02 amRegarding the seoncd
issue: if these are valid opcodes, IMO there is no reason NOT to raise
the bugtracker issue.

All I can say is that they are documented in 64-ia-32-architectures-
software-developer-manual-325462 and belong to the category general
purpose instructions ...

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BigChimp · 2014-07-31 08:26

Don't post here, post on the bugtracker  <smiles> (& thanks!)

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engkin · 2014-07-31 21:10

For limited usage of these missing opcodes, you might be able to do
your tests with something like:
Code: [Select]     //adcx    RAX, [RBX+8*RDX];   // Add and only
affect CF
     db 066H db 048H db 00FH db 038H db 0F6H db 004H db 0D3H
I used Flat Assembler to get these numbers.

If you do write a bug report, please post a link to it here.

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marcov · 2014-08-01 09:56

Stock Lazarus is 32-bit, are you sure you installed the 64-bit
crosscompiler and selected it a 64-bit target, since that is 64-bit
assembler?

The FASM hex looks strange, using the db66 escape prefix, which means
that that instruction is not in native 64-bit mdoe?

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engkin · 2014-08-01 12:29

The same instruction 32bit:
Code: [Select]  //adcx    EAX, [EBX+8*EDX]
  db 066h db 00Fh db 038h db 0F6h db 004h db 0D3

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marcov · 2014-08-01 12:35

Hmm, if I google a bit, seems that these are Broadwell instructions.
These chips are only sampling at the moment, so this is very bleeding
edge.

Seems trunk hasn't got them yet either.