Changes between Version 17 and Version 18 of PortableRrdFormat


Ignore:
Timestamp:
Jun 21, 2007, 9:51:16 AM (15 years ago)
Author:
oetiker
Comment:

--

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  • PortableRrdFormat

    v17 v18  
    152152}}}
    153153
     154Alpha
     155{{{
     156    0.000000e+00 ->  00 00 00 00 00 00 00 00
     157    1.000000e+00 ->  00 00 00 00 00 00 f0 3f
     158   -1.000000e+00 ->  00 00 00 00 00 00 f0 bf
     159            NaNQ ->  00 00 00 00 00 00 f8 ff
     160             INF ->  00 00 00 00 00 00 f0 7f
     161            -INF ->  00 00 00 00 00 00 f0 ff
     162    2.000000e+00 ->  00 00 00 00 00 00 00 40
     163    4.000000e+00 ->  00 00 00 00 00 00 10 40
     164    8.000000e+00 ->  00 00 00 00 00 00 20 40
     165    1.600000e+01 ->  00 00 00 00 00 00 30 40
     166   8.642135e+130 ->  2f 25 c0 c7 43 2b 1f 5b
     167}}}
     168
    154169As you can see, there is not all that much difference between the architectures (it is all IEEE 754 after all). For one there is the endianess difference and then there are some differing ideas regarding NANs. In any event, a converter between these formats is only a few defines away.
    155170
     
    207222                                       : A )
    208223
     224#define alpha2x86(A)   ((uint64_t)(A) == 0x000000000000f8ffLL \
     225                                       ? 0x000000000000f87fLL \
     226                                       : A )
     227
     228#define x862alpha(A)   ((uint64_t)(A) == 0x000000000000f87fLL \
     229                                       ? 0x000000000000f8ffLL \
     230                                       : A )
     231
     232
    209233}}}
    210234
     
    253277
    254278Based on this information a portable RRDtool data format that works at least on
    255 PPC, x86, Itanium, PARISC, ARM4, ARM5 and SPARC will be not all that difficult to design.
    256 
    257 Information on other architectures is welcome: Alpha, MIPS.
     279PPC, x86, Itanium, PARISC, ARM4, ARM5, Alpha and SPARC will be not all that difficult to design.
     280
     281Information on other architectures is welcome: MIPS.

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