360 Assembly/360 Instructions/SPM

SPM — Set Program Mask — Opcode 04 / Decimal 04 — 2 byte RR Instruction.

Format

SPM program_mask_register, unused

SPM 1, 0 (Register 1 would contain the new mask, note that only the first 4 bits will be used.)

Availability

The SPM instruction can be used on the 360, 370, 390, and System/Z.

Purpose of Instruction

The SPM instruction changes the program mask and so masking arithmetic exceptions against causing an interrupt.

• Bit 0 - Integer overflow
• Bit 1 - Decimal overflow
• Bit 2 - Floating-point underflow
• Bit 3 - Floating-point overflow