Intel 80287, 80286 manual Programming Facilities, High-Level Languages

PROGRAMMING NUMERIC APPLICATIONS

10ccurs when one or both operands is "short"-it has 40 trailing zeros in its fraction (e.g., it was loaded from a short-real memory operand.

2The 80287 execution clock count for this instruction is not meaningful in determining overall instruction execution time. For typical frequency ratios of the 80286 and 80287 clocks, 80287 execution occurs in parallel with the operand transfers, with the operand transfers determining the overall execution time of the instruction. For 80286:80287 clock frequency ratios of 4:8,1:1, and 8:5, the overall execution clock count for this instruction is estimated at 490,302, and 22780287 clocks, respectively.

3The 80287 execution clock count for this instruction is not meaningful in determining overall instruction execution time. For typical frequency rations of the 80286 and 80287 clocks, 80287 execution Occurs in parallel with the operand transfers, with the operand transfers determining the overall execution time of the instruction. For 80286:80287 clock frequency ratios of 4:8, 1:1, and 8:5, the overall execution clock count for this instruction is estimated at 376,233, and 17480287 clocks, respectively.

4n = number of times CPU examines BUSY line before 80287 completes execution of previous instruction.

PROGRAMMING FACILITIES

As described previously, the 80287 NPX is programmed simply as an extension of the 80286 CPU. This section describes how programmers in ASM286 and in a variety of higher-level languages can work with the 80287.

The level of detail in this section is intended to give programmers a basic understanding of the software tools that can be used with the 80287, but this information does not document the full capabilities of these facilities. For a complete list of documentation on all the languages available for 80286 systems, readers should consult Intel's Literature Guide.

High-Level Languages

For programmers using high-level languages, the programming and operation of the NPX is handled automatically by the compiler. A variety of Intel high-level languages are available that automatically make use of the 80287 NPX when appropriate. These languages include

PL/M-286

FORTRAN-286

PASCAL-286

C-286

hach of these .high-h;vd li:i.iigiiagcs hus ~peci:l! n!!mer!<: \ihrllries allowing programs to take advantage of the capabilities of the 80287 NPX. No special programming conventions are necessary to make use of the 80287 NPX when programming numeric applications in any of these languages.

Programmers in PL/M-286 and ASM286 can also make use of many of these library routines by using routines contained in the 80287 Support Library, described in the 80287 Support Library Reference Manual, Order Number 122129. These library routines provide many of the functions provided by higher-level languages, including exception handlers, ASCII-to-floating-point conversions, and a more complete set of transcendental functions than that provided by the 80287 instruction set.

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