| ARM Neon reference tests |
| ======================== |
| This package contains extensive tests for the ARM/Neon instructions. |
| |
| It works by building a program which uses all of them, and then |
| executing it on an actual target or a simulator. |
| |
| It can be used to validate the simulator against an actual HW target, |
| or to validate C compilers in presence of Neon intrinsics calls. |
| |
| The supplied Makefile enables to build with both ARM RVCT compiler and |
| GNU GCC (for the ARM target), and supports execution with ARM RVDEBUG |
| on an ARM simulator and with QEMU. |
| |
| For convenience, the ARM ELF binary file (as compiled with RVCT) is |
| supplied (compute_ref.axf), as well as expected output (ref-rvct.txt). |
| |
| A second file containing expected output is also supplied: |
| ref-rvct-neon.txt, which contains only the results of the Neon |
| instrinsics tests. It is aimed at being used to check GCC's results, |
| since this compiler does not support the integer & dsp builtins whose |
| results are also present in ref-rvct.txt. |
| |
| Typical usage when used to debug QEmu: |
| $ make all # to build the test program with ARM rvct and execute with QEmu |
| $ make check # to compare the results with the expected output |
| |
| |
| Known issues: |
| ------------- |
| Some tests currently fail to build with GCC/ARM: |
| - missing include files: dspfns.h, armdsp.h |
| |
| As GCC/ARM provides no support for the |
| Neon_Cumulative_Saturation/fpsrc register, auxiliary accessor |
| functions have been implemented in stm-arm-neon-ref.h. |
| |
| Engineering: |
| ------------ |
| In order to cover all the Neon instructions extensively, these tests |
| make intensive use of the C-preprocessor, to save maintenance efforts. |
| |
| Most tests (the more regular ones) share a common basic structure. In |
| general, variable names are suffixed by their type name, so as to |
| differentiate variables with the same purpose but of differente types. |
| Hence vector1_int8x8, vector1_int16x4 etc... |
| |
| For instance in ref_vmul.c the layout of the code is as follows: |
| |
| - declare input and output vectors (named 'vector1', 'vector2' and |
| 'vector_res') of each possible type (s/u, 8/16/32/64 bits). |
| |
| - clean the result buffers. |
| |
| - initialize input vectors 'vector1' and 'vector2'. |
| |
| - call each variant of the intrinsic and store the result in a buffer |
| named 'buffer', whose contents is printed after execution. |
| |
| One can then compare the actual result with the expected one. |
