EDIT: Said Wikipedia page was sufficiently detailed for me to implement a Brainfuck -> MSIL compiler without additional external references, which I was able to verify worked with a Mandelbrot renderer.

> Subtract and branch if not equal to zero[edit] > The SBNZ a,b,c,d instruction ("Subtract and Branch if Not equal to Zero") subtracts the contents at address a from the contents at address b, stores the result at address c, and then, if the result is not 0, transfers control to address d (if the result is equal zero, execution proceeds to the next instruction in sequence).

This is all of it.