Support nested LOAD

This commit is contained in:
Virgil Dupras 2020-04-14 21:04:07 -04:00
parent aec19e5c87
commit 415bd7a169
4 changed files with 35 additions and 10 deletions

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@ -1,3 +1,4 @@
(cont.)
UNTIL f -- *I* Jump backwards to BEGIN if f is
false.
EXIT! -- Exit current INTERPRET loop.

1
blk/103 Normal file
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@ -0,0 +1 @@
42 . 102 LOAD 43 .

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@ -7,14 +7,12 @@
: BLK!* 2 BLKMEM+ ;
( Current blk pointer in ( )
: BLK> 4 BLKMEM+ ;
( backup for CINPTR when LOADing )
: BLKC<* 6 BLKMEM+ ;
: BLK( 8 BLKMEM+ ;
: BLK( 6 BLKMEM+ ;
: BLK$
H@ 0x57 RAM+ !
( 1024 for the block, 8 for variables )
1032 ALLOT
( 1024 for the block, 6 for variables )
1030 ALLOT
( LOAD detects end of block with ASCII EOT. This is why
we write it there. EOT == 0x04 )
4 C,
@ -42,17 +40,33 @@
DUP 4 = IF
DROP
( We're finished interpreting )
BLKC<* @ 0x0c RAM+ !
C<
EXIT!
THEN
;
: LOAD
( save BLK>, CINPTR and boot< ptr to RSP )
BLK> @ >R
0x0c RAM+ @ >R
0x2e RAM+ @ >R
BLK@
( 2e == BOOT C< PTR )
( Point to beginning of BLK )
BLK( 0x2e RAM+ !
( Save current C< ptr )
0x0c RAM+ @ BLKC<* !
( 0c == CINPTR )
['] _ 0x0c RAM+ !
INTERPRET
R> 0x2e RAM+ !
( Before we restore CINPTR, are we restoring it to "_"?
if yes, it means we're in a nested LOAD which means we
should also load back the saved BLK>. Otherwise, we can
ignore the BLK> from RSP. )
I 0x0c RAM+ @ = IF
( nested load )
R> DROP ( CINPTR )
R> BLK@
ELSE
( not nested )
R> 0x0c RAM+ !
R> DROP ( BLK> )
THEN
;

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@ -149,3 +149,12 @@
LIT< _sys (find) NOT IF ABORT THEN
DUP HERE ! CURRENT !
;
( Drop RSP until I-2 == INTERPRET. )
: EXIT!
['] INTERPRET ( I )
BEGIN ( I )
DUP ( I I )
R> DROP I 2 - @ ( I I a )
= UNTIL
;