Some ASM help.

I'm wondering if anybody could help me with a few things in ASM, I've followed a guide to port spindash to Sonic 1, and it functions correctly apart from the camera. How would I go about making the camera lock horizontally until Sonic approaches the edge of the screen, as he does in the other games? And also how might I fix the problem where Sonic's animation changes to walking when you jump beside an object? Any help would be greatly appreciated.