SY.REG - registers after MME.MME or DRL.DRL.

Description:

When DRL.DRL or MME.MME is used to perform a system call that does a normal return (i.e. the system call does not branch back to the caller), the routine saves the registers in "sy.reg" using an SREG instruction after the DRL or MME has finished. Note that the externals "drl.a", "drl.q", "mme.a" and "mme.q" are part of "sy.reg".

"sy.reg" is particularly handy when using DRL JOUT, a DRL which returns data in the index registers as well as the A and Q.