operators.js

'use strict';

function half(arg) {
  const name = arg.name;
  const width = arg.width;
  return [`${name}[${width / 2 - 1}:0]`, `${name}[${width - 1}:${width / 2}]`];
}

function signed(op) {
  return function(args) {
    const args2 = (args.length === 1) ? half(args[0]) : args.map(e => e.name);
    return '(' + args2.map(e => '$signed(' + e + ')').join(' ' + op + ' ') + ')';
  };
}

function logical(op) {
  return function(args) {
    const args2 = (args.length === 1) ? half(args[0]) : args.map(e => e.name);
    return '(' + args2.join(' ' + op + ' ') + ')';
  };
}

module.exports = {

  /*
  **   exponentiation,  numeric ** integer,  result numeric
  abs  absolute value,  abs numeric,  result numeric
  not  complement,      not logic or boolean,  result same

  *    multiplication,  numeric * numeric,  result numeric
  /    division,        numeric / numeric,  result numeric
  mod  modulo,          integer mod integer,  result integer
  rem  remainder,       integer rem integer,  result integer

  +    unary plus,      + numeric,  result numeric
  -    unary minus,     - numeric,  result numeric

  +    addition,        numeric + numeric,  result numeric
  -    subtraction,     numeric - numeric,  result numeric
  &    concatenation,   array or element & array or element,
                          result array
  */

  add: signed('+'),
  '+': signed('+'),
  sub: signed('-'),
  '-': signed('-'),
  mul: signed('*'),
  '*': signed('*'),

  sll: logical('<<'), // shift left logical,     logical array sll integer,  result same
  srl: logical('>>>'), // shift right logical,    logical array srl integer,  result same
  sla: logical('<<'), // shift left arithmetic,  logical array sla integer,  result same
  sra: logical('>>'), // shift right arithmetic, logical array sra integer,  result same
  rol: logical('rol'), // rotate left,            logical array rol integer,  result same
  ror: logical('ror'), // rotate right,           logical array ror integer,  result same

  /*
  =    test for equality, result is boolean
  /=   test for inequality, result is boolean
  <    test for less than, result is boolean
  <=   test for less than or equal, result is boolean
  >    test for greater than, result is boolean
  >=   test for greater than or equal, result is boolean
  */

  and: logical('&'), // logical and,                logical array or boolean,  result is same
  or: logical('|'), // logical or,                 logical array or boolean,  result is same
  nand: logical('&'), // logical complement of and,  logical array or boolean,  result is same
  nor: logical('|'), // logical complement of or,   logical array or boolean,  result is same
  xor: logical('^'), // logical exclusive or,       logical array or boolean,  result is same
  xnor: logical('^'), // logical complement of exclusive or,  logical array or boolean,  result is same

  concat: args => '{' + args.reverse().map(e => e.name).join(', ') + '}'
};