Good job! I am not able to do anything like that due to lack of expertise in
assembly language and lack of time to figure that out. However I have found
that reva forth (http://ronware.org/reva/) and retroforth
(http://www.retroforth.org/) have implemented the callbacks. Reva code for
the callbacks looks like:
variable cb-param-base
: cb-param ( n -- m ) 1+ cells cb-param-base @ + @ ;
: cb-setup (s0) @ >rr sp cell+ cell+ (s0) ! cb-param-base xchg >rr ;
: cb-teardown rr> rr> (s0) ! cb-param-base ! ;
: cb: ( xt stacksize <name> -- )
cells allot | save that many bytes out of 'here'
here cell-
| ( xt newstack <name> -- )
| now, create the callback entity:
header
| fill in "stuff":
$e089 2, | mov eax, esp -- use TOS as the offset
$50 1, | push eax -- temporary area for returned EAX
$60 1, | pusha ( pushed eight registers on-stack )
$be 1, | mov esi, imm32
, | 'here' which was beginning of our stack
['] cb-setup compile
| ( xt -- )
$bb 1, , | mov ebx, imm32 (xt)
$d3ff 2, | call dword ebx
['] cb-teardown compile
$20244489 , | mov [esp+32], eax | save till after popa
$61 1, | popa
$58 1, | pop eax -- get EAX result
$c3 1, | ret
;
and is used as:
:: ( buttonptr -- ) 0 cb-param ['] blocks setpat ; 20 cb: blocks-cb
but you can find the details in the corresponding code trees of those forths
It would be great if one could figure out how to translate it to bigforth.
I've failed so far to make it working :(
On Monday 18 December 2006 18:29, Don Venhaus wrote:
> Also, I'm not sure how to
> return a value.
--
Sergey
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