| OCR Text |
Show 43 Pragmatics Both routines are called and executed like any other sxmple procedure. Justification These routines allow the user to extract an arbitrary sequence of bits from some other sequence of bits. Examples: a *■ array (7, 1 to 10, -255 to 0) ' ' 'a is mapped as a two-dimensionaT array whose elements are 7 bits wide''' a t-f -3] ,,,selection of a byte''' a [5,1 '"selection of a row'" a [2 to 5, -10 to -2] ,,,selection of a new square array''' id *- field. (0 to 15) ; wages *■ field (16 to 31) ; son *■ field (32 to 32 + 16) ; son 2 + field (32 + 15 to 63); '•'this is a definition of the fields of a 64 bit wide record, a use follows''1 employee + array (64, üFto'.lGOO) ; employee ■*• tape 2; display «■ wages (employee [3 to 15]), display ■*- employee [son (employee [5])] |
