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Big Number Functions
- CosmBNInit
- CosmBNSet
- CosmBNSets32
- CosmBNGets32
- CosmBNCmp
- CosmBNOdd
- CosmBNZero
- CosmBNBits
- CosmBNAdd
- CosmBNSub
- CosmBNMul
- CosmBNDiv
- CosmBNMod
- CosmBNModExp
- CosmBNModInv
- CosmBNGCD
- CosmBNPrimeRM
- CosmBNPrimeGen
- CosmBNStr
- CosmBNPrint
- CosmBNFree
- CosmBNLoad
- CosmBNSave
CosmBNInit
Syntax
#include "cosm/bignum.h" s32 CosmBNInit( cosm_BN * x );
Description
Initialize the bignum to 0. This isn't neccesary if you have allocated the cosm_BN with CosmMemAlloc. The library will handle numbers up to 2^31 - 64 bits in length or the limit of memory.
Return Values
COSM_PASS or COSM_FAIL on an error.
Errors
Example
CosmBNSet
Syntax
#include "cosm/bignum.h" s32 CosmBNSet( cosm_BN * x, const cosm_BN * a );
Description
x = a.
Return Values
COSM_PASS or COSM_FAIL on an error.
Errors
Example
CosmBNSets32
Syntax
#include "cosm/bignum.h" s32 CosmBNSets32( cosm_BN * x, const s32 a );
Description
x = (s32) a.
Return Values
COSM_PASS or COSM_FAIL on an error.
Errors
Example
CosmBNGets32
Syntax
#include "cosm/bignum.h" s32 CosmBNGets32( s32 * x, const cosm_BN * a );
Description
x = (s32) a. Nasty truncation will occur if the number is more then 31 bits long.
Return Values
COSM_PASS or COSM_FAIL on an error.
Errors
Example
CosmBNCmp
Syntax
#include "cosm/bignum.h" s32 CosmBNCmp( const cosm_BN * a, const cosm_BN * b );
Description
Compare the numbers a and b.
Return Values
-1 if a < b, 0 if a == b, 1 if a > b.
Errors
Example
CosmBNOdd
Syntax
#include "cosm/bignum.h" s32 CosmBNOdd( const cosm_BN * x );
Description
Is x odd?
Return Values
1 if x is odd, 0 if even.
Errors
Example
CosmBNZero
Syntax
#include "cosm/bignum.h" s32 CosmBNZero( const cosm_BN * x );
Description
Is x zero?
Return Values
1 if x is zero, 0 otherwise.
Errors
Example
CosmBNBits
Syntax
#include "cosm/bignum.h" s32 CosmBNBits( u32 * x, const cosm_BN * a );
Description
x = bits in a, could be 0.
Return Values
COSM_PASS or COSM_FAIL on an error.
Errors
Example
CosmBNAdd
Syntax
#include "cosm/bignum.h" s32 CosmBNAdd( cosm_BN * x, const cosm_BN * a, const cosm_BN * b );
Description
x = a + b.
Return Values
COSM_PASS or COSM_FAIL on an error.
Errors
Example
CosmBNSub
Syntax
#include "cosm/bignum.h" s32 CosmBNSub( cosm_BN * x, const cosm_BN * a, const cosm_BN * b );
Description
x = a - b.
Return Values
COSM_PASS or COSM_FAIL on an error.
Errors
Example
CosmBNMul
Syntax
#include "cosm/bignum.h" s32 CosmBNMul( cosm_BN * x, const cosm_BN * a, const cosm_BN * b );
Description
x = a * b.
Return Values
COSM_PASS or COSM_FAIL on an error.
Errors
Example
CosmBNDiv
Syntax
#include "cosm/bignum.h" s32 CosmBNDiv( cosm_BN * x, const cosm_BN * a, const cosm_BN * b );
Description
x = a / b.
Return Values
COSM_PASS or COSM_FAIL on an error.
Errors
Example
CosmBNMod
Syntax
#include "cosm/bignum.h" s32 CosmBNMod( cosm_BN * x, const cosm_BN * a, const cosm_BN * b );
Description
x = a % b.
Return Values
COSM_PASS or COSM_FAIL on an error.
Errors
Example
CosmBNModExp
Syntax
#include "cosm/bignum.h" s32 CosmBNModExp( cosm_BN * x, const cosm_BN * a, const cosm_BN * e, const cosm_BN * m );
Description
x = a to the e-th power modulo m.
Return Values
COSM_PASS or COSM_FAIL on an error.
Errors
Example
CosmBNModInv
Syntax
#include "cosm/bignum.h" s32 CosmBNModInv( cosm_BN * x, const cosm_BN * a, const cosm_BN * m );
Description
x = Inverse of a modulo m.
Return Values
COSM_PASS or COSM_FAIL on an error.
Errors
Example
CosmBNGCD
Syntax
#include "cosm/bignum.h" s32 CosmBNGCD( cosm_BN * x, const cosm_BN * a, const cosm_BN * b );
Description
x = Greatest Common Divisor (GCD) of a and b. 1 if a and b are relatively prime.
Return Values
COSM_PASS or COSM_FAIL on an error.
Errors
Example
CosmBNStr
Syntax
#include "cosm/bignum.h" s32 CosmBNStr( cosm_BN * x, void ** end, const void * string, u32 radix );
Description
Convert the string written in radix to the bignum x. Numbers are of the form: [space*][+|-][0|0x|0X]{0-9a-zA-Z}+ radix must be 2-36 or 0. If radix is 0, numbers starting with 0x|0X will be read as base 16, numbers starting with 0 will be interpreted as base 8, and all others will be base 10. If end is not NULL, it will be set to the character after the last character used in the number. Note that use of radixes other then 2, 8, 10, or 16 are generally useless.
Return Values
Sets result to number and returns COSM_PASS on success, or sets result to 0 and returns COSM_FAIL on failure.
Errors
Example
CosmBNPrint
Syntax
#include "cosm/bignum.h" u32 CosmBNPrint( cosm_FILE * file, utf8 * string, u32 max_bytes, u32 radix, cosm_BN * x );
Description
Prints x to the string in the radix. No more than max_bytes-1 characters will be written to the string. radix must be from 2 and 16.
Return Values
Number of characters written to string, or -1 if truncated due to max_bytes.
Errors
Example
CosmBNFree
Syntax
#include "cosm/bignum.h" void CosmBNFree( cosm_BN * x );
Description
Free the bignum internals.
Return Values
COSM_PASS or COSM_FAIL on an error.
Errors
Example
CosmBNLoad
Syntax
#include "cosm/bignum.h" s32 CosmBNLoad( cosm_BN * x, const u8 * bytes, u32 bits );
Description
Load bits bits of big endian bytes into x. bits must be a multiple of 8. The largest number you can load is 2^31 - 64 bits long (COSM_BN_MAXBITS). Do not load more bits the number originally had when saved.
Return Values
COSM_PASS or COSM_FAIL on an error.
Errors
Example
CosmBNSave
Syntax
#include "cosm/bignum.h" s32 CosmBNSave( u8 * bytes, const cosm_BN * x, u32 max_bits, u32 min_bits );
Description
Save x into bytes in big endian order. If the number is more then max_bits long the function will fail and no bytes will be saved. The largest number you can save is 2^31 - 64 bits long (COSM_BN_MAXBITS). Care should be taken to record how many bits were in the number for later loading.
Return Values
COSM_PASS or COSM_FAIL on an error.
Errors
Example
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Document last modified: Jun 01, 2012