Not unlike the move-long (MVCL) and compare-long (CLCL) instructions in the MVS Architecture (IBM OS/370, OS/390, z-OS, or whatever they are calling it today). The instructions operate on blocks of data up to 2^^24 bytes in length, but the micro-code stores state and take interupts every 1024 bytes. The Architecture also has save-state and resume-state functions implemented as single instructions, and hardware save-areas reserved for six different kinds of interupts, so it is easy to receive interupts in a timely fashion.

IIRC, before the advent of the outboard I/O Subsystem, all of the I/O programming was done the same way -- start a transfer of 32 bytes, wait for it to finish, check status, transfer-in-channel back to the start of the I/O command chain; the TIC instruction was interupatable, the channel commands weren't.