1 /*
2 * PROJECT C Library, X68000 PROGRAMMING INTERFACE DEFINITION
3 * --------------------------------------------------------------------
4 * This file is written by the Project C Library Group, and completely
5 * in public domain. You can freely use, copy, modify, and redistribute
6 * the whole contents, without this notice.
7 * --------------------------------------------------------------------
8 * $Id: _round.c,v 1.1.1.2 1999/01/20 04:59:39 matz Exp $
9 */
10 /* changed 1997.2.2 by K.Okabe */
11
12 /* System headers */
13 #include <stdlib.h>
14 #include <sys/xstdlib.h>
15
16 /* Functions */
17 int _round (char *top, char *cur, int undig)
18 {
19 char *ptr;
20
21 /* 最後が5未満なら丸めは必要ない */
22 if (undig < '5')
23 return 0;
24
25 /* ポインタ設定 */
26 ptr = cur - 1;
27
28 /* 先頭まで戻りながら丸め処理 */
29 while (ptr >= top) {
30
31 /* 繰り上がらなければそれで終わり */
32 if (++(*ptr) <= '9')
33 return 0;
34
35 /* その桁を0に戻す */
36 *ptr-- = '0';
37
38 }
39
40 /* 先頭を1にする */
41 *++ptr = '1';
42
43 /* 繰り上がりをしらせる */
44 return 1;
45 }