AppletTalk.com Java discussions newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  need code to convert float format to internal java float for          AppletTalk.com Forum Index -> JVM, native methods and hardware View previous topic :: View next topic   Author Message Andy Guest Posted: Fri May 07, 2004 2:44 pm    Post subject: need code to convert float format to internal java float for JVM structure CONSTANT_Float_info keeps float value in 4 bytes integer type. I need code to convert float to 4 bytes according to JVM spec Thanks a lot Back to top Thomas Fritsch Guest Posted: Fri May 07, 2004 3:23 pm    Post subject: Re: need code to convert float format to internal java float Andy wrote: Quote: JVM structure CONSTANT_Float_info keeps float value in 4 bytes integer type. I need code to convert float to 4 bytes according to JVM spec Thanks a lot float f = ...; int i = Float.floatToIntBits(f); See [url]http://java.sun.com/j2se/1.4.2/docs/api/java/lang/Float.html#floatToIntBits(float[/url]) -- Thomas<dot>Fritsch<squiggle>ops<dot>de Back to top Andy Guest Posted: Sat May 08, 2004 3:00 pm    Post subject: Re: need code to convert float format to internal java float Thanks But I need piece of code written in C. Quote: JVM structure CONSTANT_Float_info keeps float value in 4 bytes integer type. I need code to convert float to 4 bytes according to JVM spec Thanks a lot float f = ...; int i = Float.floatToIntBits(f); See [url]http://java.sun.com/j2se/1.4.2/docs/api/java/lang/Float.html#floatToIntBits([/url] float) Quote: -- Thomas<dot>Fritsch<squiggle>ops<dot>de Back to top Andy Guest Posted: Mon May 10, 2004 1:26 pm    Post subject: Re: need code to convert float format to internal java float This is code to convert bytes to float. I need the reverse of this bytes The bytes item of the CONSTANT_Integer_info structure represents the value of the int constant. The bytes of the value are stored in big-endian (high byte first) order. The bytes item of the CONSTANT_Float_info structure represents the value of the float constant in IEEE 754 floating-point single format (§3.3.2). The bytes of the single format representation are stored in big-endian (high byte first) order. The value represented by the CONSTANT_Float_info structure is determined as follows. The bytes of the value are first converted into an int constant bits. Then: * If bits is 0x7f800000, the float value will be positive infinity. * If bits is 0xff800000, the float value will be negative infinity. * If bits is in the range 0x7f800001 through 0x7fffffff or in the range 0xff800001 through 0xffffffff, the float value will be NaN. * In all other cases, let s, e, and m be three values that might be computed from bits: int s = ((bits >> 31) == 0) ? 1 : -1; int e = ((bits >> 23) & 0xff); int m = (e == 0) ? (bits & 0x7fffff) << 1 : (bits & 0x7fffff) | 0x800000; Then the float value equals the result of the mathematical expression s·m·2e-150. Back to top Pete Kirkham Guest Posted: Mon May 10, 2004 7:24 pm    Post subject: Re: need code to convert float format to internal java float Andy wrote: Quote: This is code to convert bytes to float. I need the reverse of this .... Then the float value equals the result of the mathematical expression s·m·2e-150. You have three choices- 1/ perform the opposite operations to what you posted and hope you don't get too bad rounding errors. 2/ look up the float representation on your machine, use the cast Daniel Sjöblom gave you, and maybe have to do some additional bit twiddling to make your machine's representation big-endian IEEE. 3/ in the unlikely event that your machine cannot support IEEE directly, find and use a IEEE library. Pete Back to top Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First         AppletTalk.com Forum Index -> JVM, native methods and hardware All times are GMT Page 1 of 1   Jump to: Select a forum Java Newsgroups----------------Java DiscussionsWeb-based java games comp.lang.java 3D Graphics API's for Java Java: Support and criticism Java System Announcements comp.lang.java.api JavaBeans Java and CORBA Java and Databases comp.lang.java.developer Java GUI Toolkits Java Help comp.lang.java.javascript JVM, native methods and hardware comp.lang.java.misc Java Language Programming Security and Java comp.lang.java.setup Java Software Tools comp.lang.java.tech ibm.software.java.linux  Non-English Java Newsgroups----------------Java Language (German)Language Java (Français)Java (Italian)  You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum Powered by phpBB © 2001, 2006 phpBB Group SEO toolkit © 2004-2006 webmedic.