03.01.2015 Views

80C186EC/80C188EC Microprocessor User's Manual

80C186EC/80C188EC Microprocessor User's Manual

80C186EC/80C188EC Microprocessor User's Manual

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

MATH COPROCESSING<br />

14.3.1.5 Constant Instructions<br />

Each constant instruction (see Table 14-5) loads a commonly used constant onto the stack. The<br />

values have full 80-bit precision and are accurate to about 19 decimal digits. Since a temporary<br />

real constant occupies 10 memory bytes, the constant instructions, only 2 bytes long, save memory<br />

space.<br />

Table 14-5. 80C187 Constant Instructions<br />

FLDZ Load + 0.1<br />

FLD1 Load +1.0<br />

FLDPI Load<br />

FLDL2T Load log 2 10<br />

FLDL2E Load log 2 e<br />

FLDLG2 Load log 10 2<br />

FLDLN2 Load log e 2<br />

14.3.1.6 Processor Control Instructions<br />

Computations do not use the processor control instructions; these instructions are available for<br />

activities at the operating system level. This group (see Table 14-6) includes initialization, exception<br />

handling and task switching instructions.<br />

Table 14-6. 80C187 Processor Control Instructions<br />

FINIT/FNINIT Initialize processor FLDENV Load environment<br />

FDISI/FNDISI Disable interrupts FSAVE/FNSAVE Save state<br />

FENI/FNENI Enable interrupts FRSTOR Restore state<br />

FLDCW Load control word FINCSTP Increment stack pointer<br />

FSTCW/FNSTCW Store control word FDECSTP Decrement stack pointer<br />

FSTSW/FNSTSW Store status word FFREE Free register<br />

FCLEX/FNCLEX Clear exceptions FNOP No operation<br />

FSTENV/FNSTENV Store environment FWAIT CPU wait<br />

14-6

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!