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Diffstat (limited to 'x68/_round.c')
-rw-r--r-- | x68/_round.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/x68/_round.c b/x68/_round.c new file mode 100644 index 0000000000..761930fb8c --- /dev/null +++ b/x68/_round.c @@ -0,0 +1,45 @@ +/* + * PROJECT C Library, X68000 PROGRAMMING INTERFACE DEFINITION + * -------------------------------------------------------------------- + * This file is written by the Project C Library Group, and completely + * in public domain. You can freely use, copy, modify, and redistribute + * the whole contents, without this notice. + * -------------------------------------------------------------------- + * $Id$ + */ +/* changed 1997.2.2 by K.Okabe */ + +/* System headers */ +#include <stdlib.h> +#include <sys/xstdlib.h> + +/* Functions */ +int _round (char *top, char *cur, int undig) +{ + char *ptr; + + /* 最後が5未満なら丸めは必要ない */ + if (undig < '5') + return 0; + + /* ポインタ設定 */ + ptr = cur - 1; + + /* 先頭まで戻りながら丸め処理 */ + while (ptr >= top) { + + /* 繰り上がらなければそれで終わり */ + if (++(*ptr) <= '9') + return 0; + + /* その桁を0に戻す */ + *ptr-- = '0'; + + } + + /* 先頭を1にする */ + *++ptr = '1'; + + /* 繰り上がりをしらせる */ + return 1; +} |