Add word "LOAD"

blk/001

@@ -1,4 +1,4 @@
 MASTER INDEX
 
   3 Usage                      30 Dictionary
- 70 Implementation notes
+ 70 Implementation notes      100 Block explorer

blk/064

@@ -3,3 +3,4 @@ Disk
 BLK> -- a Address of the current block variable.
 LIST n -- Prints the contents of the block n on screen in the
           form of 16 lines of 64 columns.
+LOAD n -- Interprets Forth code from block n

blk/100

@@ -0,0 +1,10 @@
+Block explorer
+
+This is an application to conveniently browse the contents of
+the disk blocks. You can launch it with "102 LOAD".
+
+USAGE: When loaded, the Forth interpreter is replaced by the
+explorer interpreter. Typing "Q" quits the program.
+
+Typing a decimal number followed by space or return lists the
+contents of that block.

blk/102

@@ -0,0 +1,2 @@
+: foo ." Hello world! " 42 . ;
+foo

forth/blk.fs

@@ -7,11 +7,17 @@
 : BLK!* 2 BLKMEM+ ;
 ( Current blk pointer in ( )
 : BLK> 4 BLKMEM+ ;
-: BLK( 6 BLKMEM+ ;
+( backup for CINPTR when LOADing )
+: BLKC<* 6 BLKMEM+ ;
+: BLK( 8 BLKMEM+ ;
 
 : BLK$
     H@ 0x57 RAM+ !
-    1030 ALLOT
+    ( 1024 for the block, 8 for variables )
+    1032 ALLOT
+    ( LOAD detects end of block with ASCII EOT. This is why
+      we write it there. EOT == 0x04 )
+    4 C,
     -1 BLK> !
 ;
 
@@ -30,3 +36,23 @@
         CRLF
     LOOP
 ;
+
+: _
+    (boot<)
+    DUP 4 = IF
+        DROP
+        ( We're finished interpreting )
+        BLKC<* @ 0x0c RAM+ !
+        C<
+    THEN
+;
+
+: LOAD
+    BLK@
+    ( 2e == BOOT C< PTR )
+    BLK( 0x2e RAM+ !
+    ( Save current C< ptr )
+    0x0c RAM+ @ BLKC<* !
+    ( 0c == CINPTR )
+    ['] _ 0x0c RAM+ !
+;

forth/icore.fs

@@ -178,7 +178,7 @@
 
 ( system c< simply reads source from binary, starting at
   LATEST. Convenient way to bootstrap a new system. )
-: (c<)
+: (boot<)
     ( 2e == BOOT C< PTR )
     0x2e RAM+ @   ( a )
     DUP C@        ( a c )
@@ -192,7 +192,7 @@
     ( 2e == SYSTEM SCRATCHPAD )
     CURRENT @ 0x2e RAM+ !
     ( 0c == CINPTR )
-    LIT< (c<) (find) DROP 0x0c RAM+ !
+    LIT< (boot<) (find) DROP 0x0c RAM+ !
     LIT< INIT (find)
     IF EXECUTE
     ELSE DROP INTERPRET THEN