Release notes for Linux Kernel VFP support code

Date: 20 May 2004

Author: Russell King

This is the first release of the Linux Kernel VFP support code. It provides support for the exceptions bounced from VFP hardware found on ARM926EJ-S.

This release has been validated against the SoftFloat-2b library by John R. Hauser using the TestFloat-2a test suite. Details of this library and test suite can be found at:

The operations which have been tested with this package are:

  • fdiv

  • fsub

  • fadd

  • fmul

  • fcmp

  • fcmpe

  • fcvtd

  • fcvts

  • fsito

  • ftosi

  • fsqrt

All the above pass softfloat tests with the following exceptions:

  • fadd/fsub shows some differences in the handling of +0 / -0 results when input operands differ in signs.

  • the handling of underflow exceptions is slightly different. If a result underflows before rounding, but becomes a normalised number after rounding, we do not signal an underflow exception.

Other operations which have been tested by basic assembly-only tests are:

  • fcpy

  • fabs

  • fneg

  • ftoui

  • ftosiz

  • ftouiz

The combination operations have not been tested:

  • fmac

  • fnmac

  • fmsc

  • fnmsc

  • fnmul