This directive controls the emulation of the coprocessor. There is no command line counterpart for this directive.
When this switch is enabled, all floating point instructions which are not supported by standard coprocessor emulators will issue a warning.
The compiler itself doesn’t do the emulation of the coprocessor.
To use coprocessor emulation under dos (go32v2) you must use the emu387 unit, which contains correct initialization code for the emulator.
Under linux and most unix’es, the kernel takes care of the coprocessor support, so this switch is not necessary on those platforms.
When the switch is on, no floating point opcodes are emitted by the code generator. Instead, internal run-time library routines are called to do the necessary calculations. In this case all real types are mapped to the single IEEE floating point type.
Remark:By default, emulation is on for non-unix targets. For unix targets, floating point emulation (if required) is handled by the operating system, and by default it is off.