REBOL [ Title: "IEEE-32" Description: "REBOL to IEEE-32 FLOAT" Date: 2004-01-28 Version: 0.0.2 Author: "Piotr Gapinski" Email: %news--rowery--olsztyn--pl File: %ieee.r Copyright: "Olsztynska Strona Rowerowa http://www.rowery.olsztyn.pl" Purpose: {Provides conversion to and from IEEE-32 float (binary)} License: "GNU Lesser General Public License (Version 2.1)" Comment: { http://sandbox.mc.edu/~bennet/cs110/flt/index.html +--------------------------------------------------------------------+ |bit |0 1 2 3 4 5 6 7 8 9 A B C D E F 0 1 2 3 4 5 6 7 8 9 A B C D E F| +--------------------------------------------------+---------------+-+ |IEEE| mantissa | exponent |s| +--------------------------------------------------+---------------+-+ UWAGA: 1. procedury obsługuja TYLKO liczby 24bitowe! (ułomnosc Rebol'a) 2. zakres -0.5 > x > 0.5 nie jest suportowany } Example: { x: to-ieee 233.76 from-ieee x } library: [ level: 'intermediate platform: 'all type: [module tool] domain: [math] tested-under: [ view 1.2.33 on [Winxp] ] support: none license: 'LGPL ] ] from-ieee: func [ "Zamienia binarna liczbe float ieee-32 na number!" [catch] dat [binary!] "liczba w formacie ieee-32" /local ieee-sign ieee-exponent ieee-mantissa] [ ieee-sign: func [dat] [either zero? ((to-integer dat) and (to-integer 2#{10000000000000000000000000000000})) [1][-1]] ;; 1 bit ieee-exponent: func [dat] [ exp: (to-integer dat) and (to-integer 2#{01111111100000000000000000000000}) ;; 8 bitow exp: (exp / power 2 23) - 127 ;; 127=[2^(k-1) - 1] (k=8 dla IEEE-32bit) ] ieee-mantissa: func [dat] [ ((to-integer dat) and (to-integer 2#{00000000011111111111111111111111})) + (to-integer (1 * power 2 23)) ;; 23 bity ] s: ieee-sign dat e: ieee-exponent dat m: ieee-mantissa dat d: s * (to-integer m) / power 2 (23 - e) ] to-ieee: func [ "Zamienia decimal! lub integer! na binary! w formacie ieee-32." [catch] dat [number!] "liczba do konwersji (24 bity)" /local ieee-sign ieee-exponent ieee-mantissa integer-to-binary] [ integer-to-binary: func [i [number!]] [debase/base to-hex i 16] ieee-sign: func [dat] [either positive? dat [0][1]] ieee-exponent: func [dat] [ ;; only for -0.5 > x > 0.5 dat: to-integer dat weight: to-integer #{800000} i: 0 forever [ i: i + 1 if ((weight and dat) = weight) [break] weight: to-integer (weight / 2) ] 24 - i + 127 ] ieee-mantissa: func [dat e] [ m: to-integer (dat * (power 2 (23 - e + 127))) m: m and to-integer 2#{0111 1111 1111 1111 1111 1111} ] s: ieee-sign dat dat: abs dat e: ieee-exponent dat m: ieee-mantissa dat e integer-to-binary to-integer (m + (e * power 2 23) + (s * power 2 31)) ]