Editing Coroutine (section)

===Assembly languages===
Machine-dependent [[assembly language]]s often provide direct methods for coroutine execution. For example, in [[MACRO-11]], the assembly language of the [[PDP-11]] family of minicomputers, the "classic" coroutine switch is effected by the instruction "JSR PC,@(SP)+", which jumps to the address popped from the stack and pushes the current (''i.e'' that of the '''next''') instruction address onto the stack. On [[VAX]]en (in [[VAX MACRO]]) the comparable instruction is "JSB @(SP)+". Even on a [[Motorola 6809]] there is the instruction "JSR [,S++]"; note the "++", as 2 bytes (of address) are popped from the stack. This instruction is much used in the (standard) 'monitor' [[ASSIST (computing)|Assist]] 09.