| (name>x) tuck (x>int) ( b xt ) |
(name>x) tuck (x>int) ( b xt ) |
| swap immediate-mask and flag-sign ; |
swap immediate-mask and flag-sign ; |
| |
|
| |
: head? ( addr -- f ) |
| |
\G heuristic check whether addr is a name token; may deliver false |
| |
\G positives; addr must be a valid address |
| |
\ we follow the link fields and check for plausibility; two |
| |
\ iterations should catch most false addresses: on the first |
| |
\ iteration, we may get an xt, on the second a code address (or |
| |
\ some code), which is typically not in the dictionary. |
| |
2 0 do |
| |
dup @ dup |
| |
if ( addr addr1 ) |
| |
dup rot forthstart within |
| |
if \ addr1 is outside forthstart..addr, not a head |
| |
drop false unloop exit |
| |
then ( addr1 ) |
| |
else \ 0 in the link field, no further checks |
| |
2drop true unloop exit |
| |
then |
| |
loop |
| |
\ in dubio pro: |
| |
drop true ; |
| |
|
| const Create ??? 0 , 3 c, char ? c, char ? c, char ? c, |
const Create ??? 0 , 3 c, char ? c, char ? c, char ? c, |
| \ ??? is used by dovar:, must be created/:dovar |
\ ??? is used by dovar:, must be created/:dovar |
| |
|
| : >head ( cfa -- nt ) \ gforth to-name |
: >head ( cfa -- nt ) \ gforth to-head |
| $21 cell do |
$21 cell do ( cfa ) |
| dup i - count $9F and + cfaligned over alias-mask + = if |
dup i - count $9F and + cfaligned over alias-mask + = |
| i - cell - unloop exit |
if ( cfa ) |
| |
dup i - cell - dup head? |
| |
if |
| |
nip unloop exit |
| |
then |
| |
drop |
| then |
then |
| cell +loop |
cell +loop |
| drop ??? ( wouldn't 0 be better? ) ; |
drop ??? ( wouldn't 0 be better? ) ; |
