stack.1

This source file contains all the stack manipulation words within the Forth kernel. As Forth is a stack based language the words herein are going to be some of the most widely used words in the entire dictionary.

sp0
( --- a1 )

This variable (pronounced "s p zero") is initialized at start of world to point to the zeroeth (bottom) address of the parameter stack. This is the same stack that the BIOS (I.E. Linux) gave to the IsForth process.

rp0
( --- a1 )

This variable (pronounced "r p zero") is initialized at start of world to point to the zeroeth (bottom) address of the return stack.