Configurations/README: reword bn_ops description.
Fixes GH#3116.
@@ -136,34 +136,38 @@ In each table entry, the following keys are significant:
to have the different variants in different
directories.
- bn_ops => Building options (was just bignum options
- in the earlier history of this option,
- hence the name). This a string of words
- that describe properties on the designated
- target platform, such as the type of
- integers used to build up the bitnum,
- different ways to implement certain ciphers
- and so on. To fully comprehend the
+ bn_ops => Building options (was just bignum options in
+ the earlier history of this option, hence the
+ name). This is a string of words that describe
+ algorithms' implementation parameters that
+ are optimal for the designated target platform,
+ such as the type of integers used to build up
+ the bignum, different ways to implement certain
+ ciphers and so on. To fully comprehend the
meaning, the best is to read the affected
source.
The valid words are:
- BN_LLONG use 'unsigned long long' in
- some bignum calculations.
- This has no value when
- SIXTY_FOUR_BIT or
- SIXTY_FOUR_BIT_LONG is given.
- RC4_CHAR makes the basic RC4 unit of
- calculation an unsigned char.
- SIXTY_FOUR_BIT processor registers
- are 64 bits, long is
- 32 bits, long long is
- 64 bits.
- SIXTY_FOUR_BIT_LONG processor registers
- are 64 bits, long is
- 64 bits.
- THIRTY_TWO_BIT processor registers
- are 32 bits.
+ THIRTY_TWO_BIT bignum limbs are 32 bits,
+ this is default if no
+ option is specified, it
+ works on any supported
+ system [unless "wider"
+ limb size is implied in
+ assembly code];
+ BN_LLONG bignum limbs are 32 bits,
+ but 64-bit 'unsigned long
+ long' is used internally
+ in calculations;
+ SIXTY_FOUR_BIT_LONG bignum limbs are 64 bits
+ and sizeof(long) is 8;
+ SIXTY_FOUR_BIT bignums limbs are 64 bits,
+ but execution environment
+ is ILP32;
+ RC4_CHAR RC4 key schedule is made
+ up of 'unsigned char's;
+ RC4_INT RC4 key schedule is made
+ up of 'unsigned int's;
EXPORT_VAR_AS_FN for shared libraries,
export vars as
accessor functions.
