poke
| Definition: | poke(atom a, object x) |
| Description: | If x is an atom, write a single byte value to memory address a.
If x is a sequence, write a sequence of byte values to consecutive memory locations starting at location a. |
| pwa/p2js: | Not supported. |
| Comments: |
There are in fact 5 other variations of the poke routine:
poke1 poke2 poke4 poke8 pokeN
which write byte/word/dword/qword value(s) to memory. The poke procedure is an alias of poke1. The pokeN routine has 3 parameters: address, value, and size(1|2|4|8). The poken procedure is a simple hll wrapper of pokeN() that defaults size to machine_word() For poke (/poke1) the lower 8 bits of each byte value, i.e. and_bits(x, #FF), are stored in memory, and likewise for poke2/4/8, the lower 16/32/64 bits of each word/dword/qword value. The poke8 function is only intended for use on 64-bit architectures, see technicalia. It is faster to write several bytes at once by poking a sequence of values, than it is to write one byte at a time in a loop. |
| Example: |
a = allocate(100) -- allocate 100 bytes in memory
-- poke one byte at a time:
poke(a,97)
poke(a+1,98)
poke(a+2,99)
-- poke 3 bytes at once:
poke(a,{97,98,99})
|
| Implementation: |
via :%opPokeN in builtins\VM\pMem.e (an autoinclude) - be warned however it is low-level complicated stuff that you do not need to know. The poken routine is (trivially) implemented in builtins\peekns.e (an autoinclude), see also the notes in peek. |
| See Also: |
peek,
allocate,
free,
call |
