^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) 2003-03-22 Ralph Siemsen <ralphs@netwinder.org>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) * Reformat all but softfloat files to get a consistent coding style.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) Used "indent -kr -i8 -ts8 -sob -l132 -ss" and a few manual fixups.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) * Removed dead code and fixed function protypes to match definitions.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) * Consolidated use of (opcode && MASK_ARITHMETIC_OPCODE) >> 20.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) * Make 80-bit precision a compile-time option. (1%)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) * Only initialize FPE state once in repeat-FP situations. (6%)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) 2002-01-19 Russell King <rmk@arm.linux.org.uk>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) * fpa11.h - Add documentation
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) - remove userRegisters pointer from this structure.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) - add new method to obtain integer register values.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) * softfloat.c - Remove float128
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) * softfloat.h - Remove float128
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) * softfloat-specialize - Remove float128
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) * The FPA11 structure is not a kernel-specific data structure.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) It is used by users of ptrace to examine the values of the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) floating point registers. Therefore, any changes to the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) FPA11 structure (size or position of elements contained
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) within) have to be well thought out.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) * Since 128-bit float requires the FPA11 structure to change
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) size, it has been removed. 128-bit float is currently unused,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) and needs various things to be re-worked so that we won't
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) overflow the available space in the task structure.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) * The changes are designed to break any patch that goes on top
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) of this code, so that the authors properly review their changes.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) 1999-08-19 Scott Bambrough <scottb@netwinder.org>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) * fpmodule.c - Changed version number to 0.95
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) * fpa11.h - modified FPA11, FPREG structures
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) * fpa11.c - Changes due to FPA11, FPREG structure alterations.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) * fpa11_cpdo.c - Changes due to FPA11, FPREG structure alterations.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) * fpa11_cpdt.c - Changes due to FPA11, FPREG structure alterations.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) * fpa11_cprt.c - Changes due to FPA11, FPREG structure alterations.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) * single_cpdo.c - Changes due to FPA11, FPREG structure alterations.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) * double_cpdo.c - Changes due to FPA11, FPREG structure alterations.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) * extended_cpdo.c - Changes due to FPA11, FPREG structure alterations.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) * I discovered several bugs. First and worst is that the kernel
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) passes in a pointer to the FPE's state area. This is defined
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) as a struct user_fp (see user.h). This pointer was cast to a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) FPA11*. Unfortunately FPA11 and user_fp are of different sizes;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) user_fp is smaller. This meant that the FPE scribbled on things
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) below its area, which is bad, as the area is in the thread_struct
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) embedded in the process task structure. Thus we were scribbling
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) over one of the most important structures in the entire OS.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) * user_fp and FPA11 have now been harmonized. Most of the changes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) in the above code were dereferencing problems due to moving the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) register type out of FPREG, and getting rid of the union variable
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) fpvalue.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) * Second I noticed resetFPA11 was not always being called for a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) task. This should happen on the first floating point exception
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) that occurs. It is controlled by init_flag in FPA11. The
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) comment in the code beside init_flag state the kernel guarantees
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) this to be zero. Not so. I found that the kernel recycles task
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) structures, and that recycled ones may not have init_flag zeroed.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) I couldn't even find anything that guarantees it is zeroed when
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) when the task structure is initially allocated. In any case
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) I now initialize the entire FPE state in the thread structure to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) zero when allocated and recycled. See alloc_task_struct() and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) flush_thread() in arch/arm/process.c. The change to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) alloc_task_struct() may not be necessary, but I left it in for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) completeness (better safe than sorry).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) 1998-11-23 Scott Bambrough <scottb@netwinder.org>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) * README.FPE - fix typo in description of lfm/sfm instructions
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) * NOTES - Added file to describe known bugs/problems
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) * fpmodule.c - Changed version number to 0.94
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) 1998-11-20 Scott Bambrough <scottb@netwinder.org>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) * README.FPE - fix description of URD, NRM instructions
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) * TODO - remove URD, NRM instructions from TODO list
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) * single_cpdo.c - implement URD, NRM
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) * double_cpdo.c - implement URD, NRM
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) * extended_cpdo.c - implement URD, NRM
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) 1998-11-19 Scott Bambrough <scottb@netwinder.org>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) * ChangeLog - Added this file to track changes made.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) * fpa11.c - added code to initialize register types to typeNone
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) * fpa11_cpdt.c - fixed bug in storeExtended (typeExtended changed to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) typeDouble in switch statement)
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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