Here are some links that will help you in anything regarding PowerPC ASM
https://mariokartwii.com/forumdisplay.php?fid=50 (subforum to PPC tutorials)
http://mkwii.com/showthread.php?tid=863 (A noob-friendly reference page for commonly used ASM instructions)
http://wiibrew.org/wiki/Assembler_Tutorial (WiiBrew's own tutorial for PPC ASM; tailored toward general programming, not for Wii Gecko Codes)
https://mariokartwii.com/showthread.php?tid=1853 (special r0 rules)
https://mariokartwii.com/showthread.php?tid=1960 (SPR/Hardware register notes)
https://mariokartwii.com/downloads/PPCManuals.zip (This contains every PPC Manual, in pdf form, that is available on the web that is for Broadway/Gekko/PPC-750CL. Also included is a handy Compiler's Writer Guide.)
https://mariokartwii.com/downloads/PPCsha.txt (sha256 checksum for the zip download)
https://mariokartwii.com/forumdisplay.php?fid=50 (subforum to PPC tutorials)
http://mkwii.com/showthread.php?tid=863 (A noob-friendly reference page for commonly used ASM instructions)
http://wiibrew.org/wiki/Assembler_Tutorial (WiiBrew's own tutorial for PPC ASM; tailored toward general programming, not for Wii Gecko Codes)
https://mariokartwii.com/showthread.php?tid=1853 (special r0 rules)
https://mariokartwii.com/showthread.php?tid=1960 (SPR/Hardware register notes)
https://mariokartwii.com/downloads/PPCManuals.zip (This contains every PPC Manual, in pdf form, that is available on the web that is for Broadway/Gekko/PPC-750CL. Also included is a handy Compiler's Writer Guide.)
https://mariokartwii.com/downloads/PPCsha.txt (sha256 checksum for the zip download)