ClickHouse/contrib/crc32-vpmsum-cmake/README.md

# To Generate crc32_constants.h 

- Run make file in `../crc32-vpmsum` directory using following options and CRC polynomial. These options should use the same polynomial and order used by intel intrinisic functions
```bash
make crc32_constants.h CRC="0x11EDC6F41" OPTIONS="-x -r -c"
```
- move the generated `crc32_constants.h` into this directory
- To understand more about this go here: https://masterchef2209.wordpress.com/2020/06/17/guide-to-intel-sse4-2-crc-intrinisics-implementation-for-simde/
- Here is the link to information about intel intrinsic functions: https://www.intel.com/content/www/us/en/docs/intrinsics-guide/index.html#text=_mm_crc32_u64&ig_expand=1492,1493,1559
Changes to support the CRC32 in PowerPC to address the WeakHash collision issue. Update the reference to support the hash values based on the specific platform 2023-01-11 04:56:16 +00:00			`# To Generate crc32_constants.h`

Addressed the review comments 2023-01-12 01:00:10 +00:00			- Run make file in `../crc32-vpmsum` directory using following options and CRC polynomial. These options should use the same polynomial and order used by intel intrinisic functions
Changes to support the CRC32 in PowerPC to address the WeakHash collision issue. Update the reference to support the hash values based on the specific platform 2023-01-11 04:56:16 +00:00			```bash
			`make crc32_constants.h CRC="0x11EDC6F41" OPTIONS="-x -r -c"`
			```
			- move the generated `crc32_constants.h` into this directory
			`- To understand more about this go here: https://masterchef2209.wordpress.com/2020/06/17/guide-to-intel-sse4-2-crc-intrinisics-implementation-for-simde/`
Addressed the review comments 2023-01-12 01:00:10 +00:00			`- Here is the link to information about intel intrinsic functions: https://www.intel.com/content/www/us/en/docs/intrinsics-guide/index.html#text=_mm_crc32_u64&ig_expand=1492,1493,1559`