Juggling software interrupts and realtime tasks

The Motorola 68k has the MOVEM instruction which takes a list of registers (a bitmap) to copy to/from consecutive memory locations. The same mnemonic is used for both directions; the assembler determines the variant based on the operands. The instruction does not use a dedicated base register for this, but you can choose from a range of addressing modes for the memory operand. The 68000 is a CISC processor, after all.