## ALP Programming Guide and Reference

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### Description

The store environment instructions write the current FPU environment to the specified destination, and then mask all floating-point exceptions. The FPU environment consists of the FPU control word, status word, tag word, and error pointer (both data and instruction).

The environment layout in memory depends on both the operand size and the current operating mode of the processor. The USE attribute of the current code segment determines the operand size: the 14-byte operand applies to a USE16 segment, and the 28-byte operand applies to a USE32 segment. Figures 6-6 through 6-8 show the environment layouts for both operand sizes in both real mode and protected mode. (In virtual-8086 mode, the real mode layout is used).