FIELD: systems and methods for underflow detection during execution of processor selected operations. SUBSTANCE: methods involve reset of first status flag, masking of exclusive underflow situation, execution of floating-point instruction, and read-out of status flag to find out whether floating-point instruction will cause unmasked exclusive underflow situation. Computer system enabling implementation of these methods has processor incorporating floating-point status register that includes "too small" status flag and underflow status flag, as well as memory device storing instruction sequences that can be executed by processor. EFFECT: enlarged functional capabilities. 10 cl, 4 dwg, 4 tbl
