From 031bfc6d725b096bb16cee9c690e7ffae7b3c230 Mon Sep 17 00:00:00 2001
From: Virgil Dupras <hsoft@hardcoded.net>
Date: Mon, 30 Mar 2020 21:48:56 -0400
Subject: [PATCH] forth: setup SYSVNXT in Forth code

---
 emul/forth/z80c.bin | Bin 1549 -> 1549 bytes
 forth/core.fs       |   4 ++++
 forth/forth.asm     |   7 ++-----
 3 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/emul/forth/z80c.bin b/emul/forth/z80c.bin
index 0133c1b74cf00c22843fa5fcd53201987da4d04d..2190a1db3602403b87ce76eaf653b1f5b85230e2 100644
GIT binary patch
delta 18
ZcmeC>>E+pw!pu5H^c+Xn=1k@#OaM7j1@Qm?

delta 18
ZcmeC>>E+pw!pyo(^Z`f4=1k@#OaMCq1}6Xj

diff --git a/forth/core.fs b/forth/core.fs
index 574b8ed..0c099a8 100644
--- a/forth/core.fs
+++ b/forth/core.fs
@@ -116,6 +116,10 @@
     2 50 @ +!
 ;
 
+( Set up initial SYSVNXT value, which is 2 bytes after its
+  own address )
+50 @ DUP 2 + SWAP !
+
 : ."
     LIT
     BEGIN
diff --git a/forth/forth.asm b/forth/forth.asm
index 92fd968..394d729 100644
--- a/forth/forth.asm
+++ b/forth/forth.asm
@@ -36,8 +36,7 @@
 ; that we can't compile a regular variable in it. SYSVNXT points to the next
 ; free space in SYSVBUF. Then, at the word level, it's a regular sysvarWord.
 .equ	SYSVNXT		@+WORD_BUFSIZE
-.equ	SYSVBUF		@+2
-.equ	RAMEND		@+SYSV_BUFSIZE
+.equ	RAMEND		@+SYSV_BUFSIZE+2
 
 ; (HERE) usually starts at RAMEND, but in certain situations, such as in stage0,
 ; (HERE) will begin at a strategic place.
@@ -179,9 +178,6 @@ forthMain:
 	ld	(CURRENT), hl
 	ld	hl, HERE_INITIAL
 	ld	(HERE), hl
-	; Set up SYSVNXT
-	ld	hl, SYSVBUF
-	ld	(SYSVNXT), hl
 	ld	hl, .bootName
 	call	find
 	push	de
@@ -531,6 +527,7 @@ litWord:
 	ld	(IP), hl
 	jp	next
 
+.fill 6
 ; *** Dict hook ***
 ; This dummy dictionary entry serves two purposes:
 ; 1. Allow binary grafting. Because each binary dict always end with a dummy