shrinking with shinkler ======================= In this example I try to integrate the amazing and generally super awsome Shrinkler exe shrinker. * [Source repository](https://bitbucket.org/askeksa/shrinkler) * [Forum thread with discussion] (http://ada.untergrund.net/?p=boardthread&id=264&page=0) This is a pretty cool bit of kit. I think you can just point an exe at it and it will produce a compressed version of the exe that it runnable. Seeing as all my examples are based on a trackloaded setup, we use it slightly differently. We shrink the "program" that our trackloaded loads as if it were data: ``` Shrinkler -d out/main.bin out/shrunk.bin ``` Shrinker does a very impressive job of shrinking data: ``` Crunching... Original After 1st pass After 2nd pass 51752 27545.297 26682.832 ``` For comparison: ``` # gzip out/main.bin # ls -l out/main.bin.gz -rwxr-xr-x 1 alpine staff 29811 Mar 16 06:04 main.bin.gz ``` So now we have compressed data we need the bootloader to decompress it after it has loaded it. See [../shared/shrinkler_bootblock.s](../shared/shrinkler_bootblock.s) for the modified bootblock. But in a nutshell it's as simple as: ``` ; a0 = compressed data lea DECOMPRESS_ADDRESS,a0 ; Where we asked the trackloaded to load the compressed data ; a1 = decompressed data destination lea BASE_ADDRESS,a1 ; The location of the decompressed code. ; a2 = progress callback, can be zero if no callback is desired. lea Callback(pc),a2 bsr ShrinklerDecompress ; -> decompress! ``` With our progress callback as simple as: ``` Callback: ;; d0 = Number of bytes decompressed so far ;; a0 = Callback argument move.l a6,-(sp) lea CUSTOM,a6 move.w d0,COLOR00(a6) ; Set wild background colors as we decompress move.l (sp)+,a6 rts ``` And then we just include the Shrinkler [decompression code](../tools/external/shrinkler/ShrinklerDecompress.S): ``` include "../tools/external/shrinkler/ShrinklerDecompress.S" ``` In the [Makefile](Makefile) we can enable or disable Shrinkler: ``` SHRINKLER=1 ``` In this example I have also started to refactor the structure of the code base ready for slightly more complex examples going forward. try it ------ * [Download disk image](bin/shrinker.adf?raw=true) * Run in SAE