aforth

commit 3b30307c5f3b6f51b17647d107fc844ef16087f8
parent 21b624f1a3a098eb8e2f54572b7d46a3ff388db9
Author: Henry Wilson <m3henry@googlemail.com>
Date:   Thu, 13 Jul 2017 18:38:38 +0100

downwards growing stack

Diffstat:
M
macros.i
 | 
6
+++---
M
main.s
 | 
15
++++++++-------

2 files changed, 11 insertions(+), 10 deletions(-)
diff --git a/macros.i b/macros.i
@@ -129,7 +129,7 @@
 #	Stack manipulation
 
 .macro	_dup
-	advance	SP
+	retreat	SP
 	mov	TOS,	(SP)
 .endm
 
@@ -156,8 +156,8 @@ verb	code	\name	"\altname\()"
 .endm
 
 .macro	minstk	depth:req
-	cmp	$stack + ( \depth * 8 ), SP
-	jge	1f
+	cmp	$stack - ( \depth * 8 ), SP
+	jle	1f
 		mov	$_uflow,	IP
 		jmp	next
 1:
diff --git a/main.s b/main.s
@@ -423,15 +423,15 @@ verb	code	DUP
 
 verb	code	drop2	"2DROP"
 	minstk	2
-_drop2:	retreat	SP
+_drop2:	advance	SP
 	mov	(SP),	TOS
-	retreat	SP
+	advance	SP
 	jmp	next
 
 verb	code	DROP
 	minstk	1
 _drop:	mov	(SP),	TOS
-	retreat	SP
+	advance	SP
 	jmp	next
 
 _uflow:	do	RESETDATA
@@ -547,8 +547,8 @@ dountil:	codeword
 #	Memory management
 
 verb	code	DEPTH
-	mov	SP,	ACC
-	sub	$stack,	ACC
+	mov	$stack,	ACC
+	sub	SP,	ACC
 	shr	ACC
 	shr	ACC
 	shr	ACC
@@ -735,13 +735,14 @@ verb	code	EXECUTE
 	minstk	1
 	mov	TOS,	WP
 	mov	(SP),	TOS
-	retreat	SP
+	advance	SP
 	jmp	*(WP)
 
 
 # "STACK"
 
-stack:	.skip	1048576
+	.skip	1048576
+stack:	.quad	0
 
 # "CORE VARIABLES"