EXPRESS(1) EXPRESS(1) NAME express, exprin, exprout, expression, expressdat - create and convert data for use in PROM lookup tables SYNOPSIS exprin > xxx.exp exprout < xxx.exp > xxx.dat expression xxx expressdat xxx DESCRIPTION The two programs exprin and exprout together form a "friendly" system for generating PROM data for an expression of a single input variable. Applications might include: 1) A table lookup for trigonometric values. This would be useful in games which need to transfer from polar to Cartesian coordinates. 2) A table lookup for logarithmic values. This would be useful for logarithmic multiplication. To create xxx.ntl which is ready to be sent to the PROM programmer use the shell script expression: expression xxx To create xxx.dat use the shell script expressdat: expressdat xxx This is helpful when you want to concatenate several expressions into a single PROM. Use cat a.dat b.dat > final.dat and then edit final.dat to insert the appropriate # SET_ADDRESS command. On line help is available for expression and expressdat. The shell script expression consists of the three programs exprin, exprout, and dat2ntl piped together. The script expressdat omits the dat2ntl program. Exprin and exprout are described below; dat2ntl is described in another document. The first program, exprin, is simply an interactive guide for creating a file to be used by exprout. The file which is created has the form shown below. It may be created and edited using an editor instead of using exprin. NUMBER_OF_STEPS = 314; START_ADDRESS = 0; INPUT_INITIAL_VALUE = 0; STEP_SIZE = .01; 128 + 127 * SIN(INPUT); Example file created by exprin and used by exprout. MIT EECS Dept. 1EXPRESS(1) EXPRESS(1) The expression must obey the following rules. An expression can be of arbitrary size. It must be in infix form. It may contain the following binary operators: +-*/ and the following unitary functions: sin, cos, tan, asin, acos, atan, sinh, cosh, tanh, log, exp, abs, and sqrt. Parentheses can be used in the usual manner. It may contain any real number and the single variable: INPUT. The variable INPUT takes NUMBER_OF_STEPS steps starting at the initial value INPUT_INI-TIAL_VALUE. Each step increments INPUT by the value of STEP_SIZE. NUMBER_OF_STEPS out-puts will be created to be sent to the PROM programmer starting at the address START_ADDRESS. The output will be rounded to the nearest integer. The parser is not case sensitive. All numbers are interpreted as decimal. Spaces are ignored. The output of exprout is in the standard form used by the program dat2ntl. FILES SEE ALSO BUGS MIT EECS Dept.
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