# or_bits

Definition: | atom x3 = or_bits(atom x1, atom x2)
Description: | Perform the logical OR operation on corresponding bits in x1 and x2. A bit in x3 will be 1 when a corresponding bit in either x1 or x2 is 1. Commonly used to set bits in a bit-field (see example 1).
pwa/p2js: | Supported.
Comments: | As of 0.8.2+ the infix operator || can be used in place of or_bits(). This function may be applied to an atom or sq_or_bits() to all elements of a sequence. The rules for sequence operations apply. The arguments must be representable as 32-bit numbers, either signed or unsigned. If you intend to manipulate full 32-bit values, you should declare your variables as atom, rather than integer. The integer type is limited to 31-bits. Results are treated as signed numbers. They will be negative when the highest-order bit is 1. Caution: many cryptographic functions and the like require unsigned 32-bit integers, especially when bit-shifting, for which or_bitsu() can be used instead.
Example 1: |
    flags = or_bits(flags,XPAD) -- apply width padding (sometime later)
Example 2: |
    a = or_bits(#0F0F0000, #12345678)
    -- a is #1F3F5678
Example 3: |
    s = sq_or_bits(#FF, {#123456, #876543, #2211})
    -- s is {#1234FF, #8765FF, #22FF}
Implementation: | pilx86.e emits inline binary directly for two initialised integers, otherwise a call to :%opOrBits in builtins\VM\pMath.e or_bitsu() is currently implemented in builtins/ubits.e (also an autoinclude), though that could probably be improved on, if needed.
See Also: | and_bits, xor_bits, not_bits, int_to_bits