This patch makes it so when you spin while carrying an item, Mario will hold the item consistently in the center of his sprite and slightly higher than he normally holds items, mainly so when you spin jump on enemies and next to enemies while holding a shell the shell will not kill the enemies. Without the patch, doing either of these things will sometimes kill the enemies and sometimes not kill the enemies depending on Mario's unpredictable spin jump animation.
If you still run into issues with held shells killing enemies Mario spin jumps off of, you can edit the y offset in the asm file pretty easily. There is a comment next to the value you'd need to edit.
Works as intended with no issues found, so, accepted. During moderation I added SA-1 compatibility and screenshots.
I also lowered the Y offset value a little more since the default value was still quite prone to sprite killing, but as mentioned in the description, the user can change this to their liking.
Note that this patch is incompatible with the SMB2 Holding Patch since they share a hijack address.