| 1 | OPERATING SYSTEM SPECIFIC POWERPC DETECTION
|
|---|
| 2 | --------------------------------------------
|
|---|
| 3 |
|
|---|
| 4 | Detection of the ability to execute POWERPC on processor requires
|
|---|
| 5 | operating system support. (The information is not available in user mode.)
|
|---|
| 6 |
|
|---|
| 7 | Currently only this feature is supported only for linux platform.
|
|---|
| 8 |
|
|---|
| 9 | HOW TO USE THIS
|
|---|
| 10 | ---------------
|
|---|
| 11 |
|
|---|
| 12 | This directory contains C code fragments that can be included in powerpc/powerpc_init.c
|
|---|
| 13 | by setting the macro PNG_POWERPC_VSX_FILE to the file name in "" or <> at build
|
|---|
| 14 | time. This setting is not recorded in pnglibconf.h and can be changed simply by
|
|---|
| 15 | rebuilding arm/arm_init.o with the required macro definition.
|
|---|
| 16 |
|
|---|
| 17 | For any of this code to be used the POWERPC code must be enabled and run time
|
|---|
| 18 | checks must be supported. I.e.:
|
|---|
| 19 |
|
|---|
| 20 | #if PNG_POWERPC_VSX_OPT > 0
|
|---|
| 21 | #ifdef PNG_POWERPC_VSX_CHECK_SUPPORTED
|
|---|
| 22 |
|
|---|
| 23 | This is done in a 'configure' build by passing configure the argument:
|
|---|
| 24 |
|
|---|
| 25 | --enable-powerpc-vsx=check
|
|---|
| 26 |
|
|---|
| 27 | FILE FORMAT
|
|---|
| 28 | -----------
|
|---|
| 29 |
|
|---|
| 30 | Each file documents its testing status as of the last time it was tested (which
|
|---|
| 31 | may have been a long time ago):
|
|---|
| 32 |
|
|---|
| 33 | STATUS: one of:
|
|---|
| 34 | SUPPORTED: This indicates that the file is included in the regularly
|
|---|
| 35 | performed test builds and bugs are fixed when discovered.
|
|---|
| 36 | COMPILED: This indicates that the code did compile at least once. See the
|
|---|
| 37 | more detailed description for the extent to which the result was
|
|---|
| 38 | successful.
|
|---|
| 39 | TESTED: This means the code was fully compiled into the libpng test programs
|
|---|
| 40 | and these were run at least once.
|
|---|
| 41 |
|
|---|
| 42 | BUG REPORTS: an email address to which to send reports of problems
|
|---|
| 43 |
|
|---|
| 44 | The file is a fragment of C code. It should not define any 'extern' symbols;
|
|---|
| 45 | everything should be static. It must define the function:
|
|---|
| 46 |
|
|---|
| 47 | static int png_have_vsx(png_structp png_ptr);
|
|---|
| 48 |
|
|---|
| 49 | That function must return 1 if POWERPC_VSX instructions are supported, 0 if not.
|
|---|
| 50 | It must not execute png_error unless it detects a bug. A png_error will prevent
|
|---|
| 51 | the reading of the PNG and in the future, writing too.
|
|---|
| 52 |
|
|---|
| 53 | BUG REPORTS
|
|---|
| 54 | -----------
|
|---|
| 55 |
|
|---|
| 56 | If you mail a bug report for any file that is not SUPPORTED there may only be
|
|---|
| 57 | limited response. Consider fixing it and sending a patch to fix the problem -
|
|---|
| 58 | this is more likely to result in action.
|
|---|
| 59 |
|
|---|
| 60 | CONTRIBUTIONS
|
|---|
| 61 | -------------
|
|---|
| 62 |
|
|---|
| 63 | You may send contributions of new implementations to
|
|---|
| 64 | [email protected]. Please write code in strict C90 C where
|
|---|
| 65 | possible. Obviously OS dependencies are to be expected. If you submit code you
|
|---|
| 66 | must have the authors permission and it must have a license that is acceptable
|
|---|
| 67 | to the current maintainer; in particular that license must permit modification
|
|---|
| 68 | and redistribution.
|
|---|
| 69 |
|
|---|
| 70 | Please try to make the contribution a single file and give the file a clear and
|
|---|
| 71 | unambiguous name that identifies the target OS. If multiple files really are
|
|---|
| 72 | required put them all in a sub-directory.
|
|---|
| 73 |
|
|---|
| 74 | You must also be prepared to handle bug reports from users of the code, either
|
|---|
| 75 | by joining the png-mng-implement mailing list or by providing an email for the
|
|---|
| 76 | "BUG REPORTS" entry or both. Please make sure that the header of the file
|
|---|
| 77 | contains the STATUS and BUG REPORTS fields as above.
|
|---|
| 78 |
|
|---|
| 79 | Please list the OS requirements as precisely as possible. Ideally you should
|
|---|
| 80 | also list the environment in which the code has been tested and certainly list
|
|---|
| 81 | any environments where you suspect it might not work.
|
|---|
