duskos

commit 3094b1728c6a6b4cf91ec9055825df1cd290cce0
parent 3ecebfc0ff6fa29ed6e9fe36979b92610a453374
Author: Virgil Dupras <hsoft@hardcoded.net>
Date:   Sat, 25 Jun 2022 07:01:41 -0400

Add sys/xhere

Diffstat:
M
fs/cc/cc.fs
 | 
2
+-
M
fs/cc/cc1.fs
 | 
4
++--
M
fs/init.fs
 | 
2
++
A
fs/sys/xhere.fs
 | 
27
+++++++++++++++++++++++++++

4 files changed, 32 insertions(+), 3 deletions(-)
diff --git a/fs/cc/cc.fs b/fs/cc/cc.fs
@@ -1,5 +1,5 @@
+\ Requires sys/scratch sys/xhere
 1 value _debug
-?f<< sys/scratch.fs
 ?f<< lib/str.fs
 ?f<< lib/wordtbl.fs
 ?f<< lib/xdict.fs
diff --git a/fs/cc/cc1.fs b/fs/cc/cc1.fs
@@ -4,6 +4,6 @@
 \ Compiles input coming from the cc< alias (defaulting to in<) and writes the
 \ result to here. Aborts on error.
 : cc1, ( -- )
-  parseast curunit _debug if dup printast nl> then
-  dup mapunit _debug if printmap then
+  xhere$ xhere[ parseast curunit _debug if dup printast nl> then
+  dup mapunit _debug if printmap then ]xhere
   gennode ;
diff --git a/fs/init.fs b/fs/init.fs
@@ -2,6 +2,8 @@
 f<< lib/core.fs
 f<< lib/annotate.fs
 f<< sys/doc.fs
+f<< sys/scratch.fs
+f<< sys/xhere.fs
 f<< sys/rdln.fs
 : init S" Dusk OS" stype nl> .free rdln$ ;
 init
diff --git a/fs/sys/xhere.fs b/fs/sys/xhere.fs
@@ -0,0 +1,27 @@
+\ Extra "here" space
+\ This subsystem is a preallocated buffer for transitionary data. It's very
+\ similar to lib/scratch, but for written (with "," words) data. Unlike the
+\ sratchpad, this is not a rolling buffer. You're expected to know when you
+\ start using it, and when you stop.
+
+\ You initialize it with here$, and then activate it with here[. From that
+\ moment, everything you write is temporary. You return to your regular "here"
+\ with ]here.
+
+\ This is used, for example, as a temporary space for the C compiler AST and
+\ mapping. Without xhere, this data is written to here and permanently uses
+\ system memory.
+
+32 1024 * const XHERESZ
+1024 const XHEREWARN
+
+create _buf XHERESZ allot
+_buf value _ptr
+0 value _oldhere
+
+: xhere$ _buf to _ptr ;
+: xhere[ here to _oldhere _ptr to here ;
+: ]xhere
+  here to _ptr _oldhere to here
+  _ptr XHEREWARN + _buf XHERESZ + > if
+    ." Running out of xhere space!" nl> then ;