Discussion:
Soft Float for AVR
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Dimitrios Chr. Ioannidis via fpc-devel
2018-07-18 12:33:02 UTC
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Hi,

AFAIU, the AVR architecture doesn't support floating point variables.

I want to ask if soft float support ( like ARM ) is planned. Does
anyone work or plan to work on this ?

regards,
--
Dimitrios Chr. Ioannidis
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Mathias
2018-07-18 14:47:47 UTC
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Hello

The AVR does not support floating-point numbers on the hardware side.
The ATtiny does not even support multiplications of Interger.
The ATMega supports least multiplications of integers.
Divisions do not support everyone.

This refers to the 8-bit AVR, as it looks with the others, I do not know.

mfg Mathias
Hi,
  AFAIU, the AVR architecture doesn't support floating point variables.
  I want to ask if soft float support ( like ARM ) is planned. Does
anyone work or plan to work on this ?
regards,
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Christo Crause
2018-07-18 19:02:55 UTC
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On Wed, 18 Jul 2018, 14:33 Dimitrios Chr. Ioannidis via fpc-devel, <
Post by Dimitrios Chr. Ioannidis via fpc-devel
Hi,
AFAIU, the AVR architecture doesn't support floating point variables.
I want to ask if soft float support ( like ARM ) is planned. Does
anyone work or plan to work on this ?
I haven't seen any commits in this regard in the last year or two for AVR.
Not sure if someone is working on it offline. I suspect it will be quite a
bit of work to generate a compact version for the AVR.
Florian Klämpfl
2018-08-20 17:26:30 UTC
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Hi,
  AFAIU, the AVR architecture doesn't support floating point variables.
  I want to ask if soft float support ( like ARM ) is planned. Does anyone work or plan to work on this ?
Problem is: the compiler throws internal errors on the softfpu unit. The code is really complex (a lot of 64 bit
operations) and the register allocator cannot cope with this.

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Florian Klämpfl
2018-08-20 20:41:21 UTC
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The Arduino C ++ supports this, but is limited to 32Bit (single).
This does not solve the softfpu problem as it is not ifdef'ed for single support only.
mfg Mathias
Post by Florian Klämpfl
Hi,
   AFAIU, the AVR architecture doesn't support floating point variables.
   I want to ask if soft float support ( like ARM ) is planned. Does anyone work or plan to work on this ?
Problem is: the compiler throws internal errors on the softfpu unit. The code is really complex (a lot of 64 bit
operations) and the register allocator cannot cope with this.
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