From e6d3638f4f71040b445d18b7daf3814e08f56023 Mon Sep 17 00:00:00 2001
From: Virgil Dupras <hsoft@hardcoded.net>
Date: Thu, 9 Apr 2020 12:01:08 -0400
Subject: [PATCH] Add CURRENT* and simplify xcomp

---
 dictionary.txt      |   2 ++
 emul/forth/xcomp.fs |   5 +++++
 emul/forth/z80c.bin | Bin 1702 -> 1731 bytes
 forth/icore.fs      |   4 +++-
 forth/xcomp.fs      |  30 ++++++++----------------------
 forth/z80c.fs       |   4 ----
 notes.txt           |   8 +++++++-
 7 files changed, 25 insertions(+), 28 deletions(-)

diff --git a/dictionary.txt b/dictionary.txt
index 3c81f3c..d526565 100644
--- a/dictionary.txt
+++ b/dictionary.txt
@@ -98,6 +98,8 @@ J           -- n            Copy RS third item to PS
 C@          a -- c          Set c to byte at address a
 C!          c a --          Store byte c in address a
 CURRENT     -- a            Set a to wordref of last added entry.
+CURRENT*    -- a            A pointer to active CURRENT*. Useful when we have
+                            multiple active dicts.
 HERE        -- a            Push HERE's address
 H@          -- a            HERE @
 MOVE        a1 a2 u --      Copy u bytes from a1 to a2, starting with a1, going
diff --git a/emul/forth/xcomp.fs b/emul/forth/xcomp.fs
index 864ed4c..73b3340 100644
--- a/emul/forth/xcomp.fs
+++ b/emul/forth/xcomp.fs
@@ -4,3 +4,8 @@
 
 CURRENT @ XCURRENT !
 H@ ' _bend - 4 + XOFF !
+
+( dummy entry for dict hook )
+(xentry) _
+H@ 256 /MOD 2 PC! 2 PC!
+
diff --git a/emul/forth/z80c.bin b/emul/forth/z80c.bin
index 66265d01c39d15266a5b52785d449f3d28de7b8e..8ffdb2ed32cd3ec50131d310dd2d31950082cd38 100644
GIT binary patch
delta 474
zcmXw#%}QHQ6ouEl=O;<=o?t;yM<>OfC=Q$y+F)Ds7%<lo^?H<;iHd)8QZ5R<fe21A
zI724|!Le^3+9xPN1tDV{86O}J_c6+zY}VR*d#`;F{f#aQY;xiwvI-i@IO7IpHA%`<
z+l!3CBe%?;xcBS#&bWe9XuA?C&P1XWG+;0@yO`J!2!%Y?!r)sDfx;rc4h^Q?dW}xU
zlJ`C8dKv+&J7>drD^d)h6?o+?JaPY7p>LD45BM5tfcQ=Fa!6edFXv9gb(n%<-qrbm
z_#&IZvHQpM)E}7-4eK&qRhi<c;|c0D&Wc%Dp9EI~J7UdX-xb6dyOK|CK@5(zDc?gF
z%YAuEU7H(9TdCS|vXqqV59AcCWF*|FSliJEiT6k&pHNJ<4i0z6;s0<$ipOYd`hDKr
zp6*&2J#SK_TCp^pB8vuUkd(TfG5A@r)w;h;Q^hiNC0U${<uhvq2Bo}z*g(byiKV|I
dML(q&&Awwe={0)S4XtmWH(SGf$6(_#f)|ZUV_5(I

delta 423
zcmXv~yGjF56rA1r*hI|66cM6@8}X5Vg@s{JM2XiR0rMa(8U<hY01IV_!H*Cm#Vy6w
zDutE3@e?crC7lp#jD=O2cyFSd<}h>4%$)Nax(_|XNh|`(h659~R3LGBc5$2>0=LnU
zIg*HWXxpekAiYv3d6Qr^!ZakW$!H|a1eQWDY!s*i18Mn4Cc<gvV+3tOBd=yvev)`J
zr?3Icn+~9qnu-fzSB}w4u*#lH9~3EhPAhDZH;sz?pw8?K51WGYHF_xb@zvD|b}#0J
zC~nVy+Dhz-G!0MAv1wB0?{bgDrdre^Ez{*5f6*NkL?D~@GNocE<1Hg-qs}{2-m%S{
zaU}f1%H>HC`p$+L)yobJv<p$}(PE!+F!%>$^I1<#`v{<hGPt^R%@SD8dikPG<fwAF
yE4O%J)#cx$Z3rxc^_!Tb<GWnD`xsW)gMoh;s_?RUQbXC-@MD$n))m-K!T1FTgkA{%

diff --git a/forth/icore.fs b/forth/icore.fs
index e445dd1..1b073e3 100644
--- a/forth/icore.fs
+++ b/forth/icore.fs
@@ -35,7 +35,8 @@
 : FLAGS 0x08 RAM+ ;
 : (parse*) 0x0a RAM+ ;
 : HERE 0x04 RAM+ ;
-: CURRENT 0x02 RAM+ ;
+: CURRENT* 0x51 RAM+ ;
+: CURRENT CURRENT* @ ;
 
 ( w -- a f )
 : (find) CURRENT @ SWAP _find ;
@@ -185,6 +186,7 @@
 ;
 
 : BOOT
+    0x02 RAM+ CURRENT* !
     LIT< (parse) (find) DROP (parse*) !
     ( 60 == SYSTEM SCRATCHPAD )
     CURRENT @ 0x60 RAM+ !
diff --git a/forth/xcomp.fs b/forth/xcomp.fs
index a3f92a8..18cec96 100644
--- a/forth/xcomp.fs
+++ b/forth/xcomp.fs
@@ -24,40 +24,26 @@
 VARIABLE XCURRENT
 VARIABLE XOFF
 
-: (xentry)
-    H@           ( h )
-    WORD         ( h s )
-    SCPY         ( h )
-    ( Adjust HERE -1 because SCPY copies the null )
-    H@ 1 -       ( h h' )
-    DUP HERE !   ( h h' )
-    -^           ( sz )
-    ( write prev value )
-    H@ XCURRENT @ - ,
-    ( write size )
-    C,
-    H@ XCURRENT !
-;
+: XCON XCURRENT CURRENT* ! ;
+: XCOFF CURRENT CURRENT* ! ;
+
+: (xentry) XCON (entry) XCOFF ;
 
 ( Finds in *both* CURRENT and XCURRENT )
 ( w -- a f xa xf )
 : (xfind)
     DUP                     ( w w )
-    CURRENT @ SWAP          ( w cur w )
+    ( hardcoded system CURRENT )
+    0x02 RAM+ @ SWAP        ( w cur w )
     _find                   ( w a f )
     ROT                     ( a f w )
     XCURRENT @ SWAP         ( a f xcur w )
     _find                   ( a f xa xf )
 ;
 
-: XCODE
-    (xentry) 23 ,
-;
+: XCODE XCON CODE XCOFF ;
 
-: XIMM
-    XCURRENT @ 1 -
-    DUP C@ 128 OR SWAP C!
-;
+: XIMM XCON IMMEDIATE XCOFF ;
 
 : X:
     (xentry)
diff --git a/forth/z80c.fs b/forth/z80c.fs
index 82dcf86..b178fad 100644
--- a/forth/z80c.fs
+++ b/forth/z80c.fs
@@ -22,10 +22,6 @@
   This unit expects the same conf as boot.fs.
 )
 
-( dummy entry for dict hook )
-(xentry) _
-H@ 256 /MOD 2 PC! 2 PC!
-
 ( a b c -- b c a )
 CODE ROT
     HL POPqq,       ( C )
diff --git a/notes.txt b/notes.txt
index 2d16513..0e71504 100644
--- a/notes.txt
+++ b/notes.txt
@@ -88,7 +88,8 @@ RAMSTART   INITIAL_SP
 +0e        WORDBUF
 +2e        SYSVNXT
 +4e        INTJUMP
-+51        RESERVED
++51        CURRENTPTR
++53        RESERVED
 +60        SYSTEM SCRATCHPAD
 +80        RAMEND
 
@@ -116,6 +117,11 @@ those slots...) in boot binaries are made to jump to this address. If you use
 one of those slots for an interrupt, write a jump to the appropriate offset in
 that RAM location.
 
+CURRENTPTR points to current CURRENT. The Forth CURRENT word doesn't return
+RAM+2 directly, but rather the value at this address. Most of the time, it
+points to RAM+2, but sometimes, when maintaining alternative dicts (during
+cross compilation for example), it can point elsewhere.
+
 SYSTEM SCRATCHPAD is reserved for temporary system storage or can be reserved
 by low-level drivers. These are the current usages of this space throughout the
 project: