[LLVMdev] 16 bit floats

[BGB]

  ----- Original Message ----- 
  From: Villmow, Micah 
  To: LLVM Developers Mailing List 
  Sent: Friday, February 06, 2009 5:47 AM
  Subject: [LLVMdev] 16 bit floats


  I need to support 16 bit floats for some operations, outside of datatypes.td and the constants class, is there anything else I will need to modify to add f16 support?



probably also code generation (can't give specifics, no real expert on the LLVM codebase).

this would be because, even if the core typesystem knows of the type, the codegen might not know how to emit operations on that type.



now, of note:

in my project (not LLVM based), float16 had not been supported directly (since it is not known to the CPU), rather, some loader and saver thunks were used which converted to/from float32 (this used as the 'internal' representation of the type). in most cases, I would think this would be faster than directly operating on the float16, since the CPU supports float32, but float16 would have to be emulated.



(unless of course newer CPUs are adding native float16 support or similar?...).







  Thanks,

   

  Micah Villmow

  Systems Engineer

  Advanced Technology & Performance

  Advanced Micro Devices Inc.

  S1-609 One AMD Place

  Sunnyvale, CA. 94085

  P: 408-749-3966

   

   



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