From mboxrd@z Thu Jan 1 00:00:00 1970 From: erik quanstrom Date: Sun, 2 Oct 2011 14:06:48 -0400 To: 9fans@9fans.net Message-ID: In-Reply-To: <20111002175227.2D7F1B856@mail.bitblocks.com> References: <20111002163800.GA12773@polynum.com> <20111002175227.2D7F1B856@mail.bitblocks.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Subject: Re: [9fans] circular fonctions: precision? Topicbox-Message-UUID: 2f4bae7e-ead7-11e9-9d60-3106f5b1d025 > > To my limited knowledge, an OS is integer based, so the floating > > point support is mainly "user space" and is, despite IEEE754 and due to > > the interaction between hardware, software, and programmer, really > > floating, but is there a range given for the association of OS/hardware > > telling that say sin(r) or asin(s) is accurate, at worst, at some > > epsilon near? > > It depends on the algorithm used, not on the OS. The C > standard leaves accuracy upto the implementation. If you care, > you can compare the result of a C function with what bc(1) > computes for the same function (by using a suitably large > scale). unless the hardware doesn't actually have floating point, doesn't this depend only on the hardware? (c.f. /sys/src/libc/386/387/sin.s) 754 defines the results to be accurate to within 1 bit. obviously that's as good as you can get. minix's math(3) points to a collection of detailed man pages on the subject. - erik