Changeset 8181f5 in git for libpolys/coeffs/longrat.cc


Ignore:
Timestamp:
Sep 7, 2012, 2:07:49 PM (12 years ago)
Author:
Oleksandr Motsak <motsak@…>
Branches:
(u'spielwiese', 'fe61d9c35bf7c61f2b6cbf1b56e25e2f08d536cc')
Children:
6dffa9e5b66ac5a81df2b68ff1c38dafc918b1f9
Parents:
f284db60abd29db5bed239271c0b6f6b1b680996
git-author:
Oleksandr Motsak <motsak@mathematik.uni-kl.de>2012-09-07 14:07:49+02:00
git-committer:
Oleksandr Motsak <motsak@mathematik.uni-kl.de>2012-09-07 19:51:24+02:00
Message:
moved the description of 'struct snumber' to longrat.h and documented the struct. members
File:
1 edited

Legend:

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Added
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  • libpolys/coeffs/longrat.cc

    rf284db r8181f5  
    6969#endif
    7070
    71 /*-----------------------------------------------------------------*/
    72 /*3
    73 * parameter s in number:
    74 * 0 (or FALSE): not normalised rational
    75 * 1 (or TRUE):  normalised rational
    76 * 3          :  integer with n==NULL
    77 */
    78 /*3
    79 **  'SR_INT' is the type of those integers small enough to fit into  29  bits.
    80 **  Therefor the value range of this small integers is: $-2^{28}...2^{28}-1$.
    81 **
    82 **  Small integers are represented by an immediate integer handle, containing
    83 **  the value instead of pointing  to  it,  which  has  the  following  form:
    84 **
    85 **      +-------+-------+-------+-------+- - - -+-------+-------+-------+
    86 **      | guard | sign  | bit   | bit   |       | bit   | tag   | tag   |
    87 **      | bit   | bit   | 27    | 26    |       | 0     | 0     | 1     |
    88 **      +-------+-------+-------+-------+- - - -+-------+-------+-------+
    89 **
    90 **  Immediate integers handles carry the tag 'SR_INT', i.e. the last bit is 1.
    91 **  This distuingishes immediate integers from other handles which  point  to
    92 **  structures aligned on 4 byte boundaries and therefor have last bit  zero.
    93 **  (The second bit is reserved as tag to allow extensions of  this  scheme.)
    94 **  Using immediates as pointers and dereferencing them gives address errors.
    95 **
    96 **  To aid overflow check the most significant two bits must always be equal,
    97 **  that is to say that the sign bit of immediate integers has a  guard  bit.
    98 **
    99 **  The macros 'INT_TO_SR' and 'SR_TO_INT' should be used to convert  between
    100 **  a small integer value and its representation as immediate integer handle.
    101 **
    102 **  Large integers and rationals are represented by z and n
    103 **  where n may be undefined (if s==3)
    104 **  NULL represents only deleted values
    105 */
    106 #define SR_HDL(A) ((long)(A))
     71//#define SR_HDL(A) ((long)(A))
    10772/*#define SR_INT    1L*/
    10873/*#define INT_TO_SR(INT)  ((number) (((long)INT << 2) + SR_INT))*/
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