2fe8fb192f
There is important information about booting non-ack images in docs/UPDATING. ack/aout-format images can't be built any more, and booting clang/ELF-format ones is a little different. Updating to the new boot monitor is recommended. Changes in this commit: . drop boot monitor -> allowing dropping ack support . facility to copy ELF boot files to /boot so that old boot monitor can still boot fairly easily, see UPDATING . no more ack-format libraries -> single-case libraries . some cleanup of OBJECT_FMT, COMPILER_TYPE, etc cases . drop several ack toolchain commands, but not all support commands (e.g. aal is gone but acksize is not yet). . a few libc files moved to netbsd libc dir . new /bin/date as minix date used code in libc/ . test compile fix . harmonize includes . /usr/lib is no longer special: without ack, /usr/lib plays no kind of special bootstrapping role any more and bootstrapping is done exclusively through packages, so releases depend even less on the state of the machine making them now. . rename nbsd_lib* to lib* . reduce mtree
74 lines
1.9 KiB
C
74 lines
1.9 KiB
C
/* $NetBSD: difftime.c,v 1.10 2009/12/31 22:49:16 mlelstv Exp $ */
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/*
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** This file is in the public domain, so clarified as of
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** 1996-06-05 by Arthur David Olson.
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*/
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#include <sys/cdefs.h>
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#if defined(LIBC_SCCS) && !defined(lint)
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#if 0
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static char elsieid[] = "@(#)difftime.c 8.1";
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#else
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__RCSID("$NetBSD: difftime.c,v 1.10 2009/12/31 22:49:16 mlelstv Exp $");
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#endif
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#endif /* LIBC_SCCS and not lint */
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/*LINTLIBRARY*/
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#include "private.h" /* for time_t, TYPE_INTEGRAL, and TYPE_SIGNED */
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double
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difftime(time1, time0)
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const time_t time1;
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const time_t time0;
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{
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/*
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** If (sizeof (double) > sizeof (time_t)) simply convert and subtract
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** (assuming that the larger type has more precision).
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** This is the common real-world case circa 2004.
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*/
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/* LINTED constant */
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if (sizeof (double) > sizeof (time_t))
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return (double) time1 - (double) time0;
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/* LINTED constant */
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if (!TYPE_INTEGRAL(time_t)) {
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/*
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** time_t is floating.
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*/
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return time1 - time0;
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}
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/* LINTED constant */
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if (!TYPE_SIGNED(time_t)) {
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/*
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** time_t is integral and unsigned.
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** The difference of two unsigned values can't overflow
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** if the minuend is greater than or equal to the subtrahend.
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*/
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if (time1 >= time0)
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return time1 - time0;
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else return -((double) (time0 - time1));
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}
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/*
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** time_t is integral and signed.
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** Handle cases where both time1 and time0 have the same sign
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** (meaning that their difference cannot overflow).
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*/
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if ((time1 < 0) == (time0 < 0))
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return time1 - time0;
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/*
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** time1 and time0 have opposite signs.
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** Punt if unsigned long is too narrow.
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*/
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/* CONSTCOND */
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if (sizeof (unsigned long) < sizeof (time_t))
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return (double) time1 - (double) time0;
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/*
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** Stay calm...decent optimizers will eliminate the complexity below.
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*/
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if (time1 >= 0 /* && time0 < 0 */)
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return (unsigned long) time1 +
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(unsigned long) (-(time0 + 1)) + 1;
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return -(double) ((unsigned long) time0 +
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(unsigned long) (-(time1 + 1)) + 1);
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}
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