baalke@mars.jpl.nasa.gov (Ron Baalke) (10/06/89)
Does anybody know where I can get the format for the IEEE standard for floating point numbers?
montnaro@sprite.crd.ge.com (Skip Montanaro) (10/07/89)
Try the Apple SANE manual(s). -- Skip Montanaro (montanaro@crdgw1.ge.com)
campbell@redsox.bsw.com (Larry Campbell) (10/07/89)
In article <1861@jato.Jpl.Nasa.Gov> baalke@mars.jpl.nasa.gov (Ron Baalke) writes:
-Does anybody know where I can get the format for the IEEE standard
-for floating point numbers?
Uh, have you tried the IEEE?
--
Larry Campbell The Boston Software Works, Inc.
campbell@bsw.com 120 Fulton Street
wjh12!redsox!campbell Boston, MA 02146johnl@esegue.segue.boston.ma.us (John R. Levine) (10/08/89)
In article <1861@jato.Jpl.Nasa.Gov> baalke@mars.jpl.nasa.gov (Ron Baalke) writes: >Does anybody know where I can get the format for the IEEE standard >for floating point numbers? The IEEE sells their publications directly. Contact: IEEE Publications Office 10662 Los Vaqueros Circle PO Box 3014 Los Alamitos CA 90720-1264 Phone +1 714 821 8380 Fax +1 714 821 4010 As I recall, the P754 floating point standard cost me about $10. -- John R. Levine, Segue Software, POB 349, Cambridge MA 02238, +1 617 492 3869 johnl@esegue.segue.boston.ma.us, {ima|lotus}!esegue!johnl, Levine@YALE.edu Massachusetts has 64 licensed drivers who are over 100 years old. -The Globe
decot@hpisod2.HP.COM (Dave Decot) (10/08/89)
IEEE Standard for Binary Floating-Point Arithmetic, ANSI/IEEE Std 754-1985. To quote from a draft version (presumably the same as the final version): Numbers in the single and double formats are composed of three fields: A 1-bit sign s. A biased exponent e = E + bias A fraction f = .b b ....b 1 2 p-1 ... A 32-bit single format number X is divided as shown in Figure 1. The value v of X is inferred from its constituent fields thus: (1) If e = 255 and f != 0, then v is NaN [not-a-number] regardless of s. (2) If e = 255 and f = 0, then v = (-1)^s * infinity. (3) If 0 < e < 255, then v = (-1)^s * 2^(e-127) * (1.f). (4) If e = 0 and f != 0, then v = (-1)^s * 2^(-126) * (0.f) (denormalized numbers). (5) If e = 0 and f = 0, then v = (-1)^s * 0 (zero). Figure 1. Single Format 1 8 23 ...widths +-+--------+----------------+ |s| e | f | +-+--------+----------------+ msb lsb msb lsb ...order "msb" means "most significant bit" "lsb" means "least significant bit" ... A 64-bit double format number X is divided as shown in Figure 2. The value v of X is inferred from its constituent fields thus: (1) If e = 2047 and f != 0, then v is NaN [not-a-number] regardless of s. (2) If e = 2047 and f = 0, then v = (-1)^s * infinity. (3) If 0 < e < 2047, then v = (-1)^s * 2^(e-1023) * (1.f). (4) If e = 0 and f != 0, then v = (-1)^s * 2^(-1022) * (0.f) (denormalized numbers). (5) If e = 0 and f = 0, then v = (-1)^s * 0 (zero). Figure 2. Double Format 1 11 52 ...widths +-+--------+----------------+ |s| e | f | +-+--------+----------------+ msb lsb msb lsb ...order (I've used "^" to signify exponentiation and "*" to signify multiplication) Hope this helps!
pozar@hoptoad.uucp (Tim Pozar) (10/10/89)
In article <1861@jato.Jpl.Nasa.Gov> baalke@mars.jpl.nasa.gov (Ron Baalke) writes: >Does anybody know where I can get the format for the IEEE standard >for floating point numbers? One place I've seen it described was in the MicroSoft C (5.1) manuals. Tim -- Tim Pozar Try also... Internet: pozar@toad.com Fido: 1:125/555 PaBell: (415) 788-3904 USNail: KKSF / 77 Maiden Lane / San Francisco CA 94108