360 Assembly/360 Instructions/SPM
SPM — Set Program Mask — Opcode 04 / Decimal 04 — 2 byte RR Instruction.
Format
[edit | edit source]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
[edit | edit source]The SPM instruction can be used on the 360, 370, 390, and System/Z.
Purpose of Instruction
[edit | edit source]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