From afbcea2d821d1166ae347338ae52a64f3ee51e57 Mon Sep 17 00:00:00 2001
From: Leo C <erbl259-lmu@yahoo.de>
Date: Wed, 29 Jun 2016 16:43:56 +0200
Subject: [PATCH] reduce stack usage

---
 cbios/msgbuf.180 | 61 ++++++++++++++++++++----------------------------
 1 file changed, 25 insertions(+), 36 deletions(-)

diff --git a/cbios/msgbuf.180 b/cbios/msgbuf.180
index 7b70d54..1bce062 100644
--- a/cbios/msgbuf.180
+++ b/cbios/msgbuf.180
@@ -95,9 +95,8 @@ bg.wait:
 	cp	(ix+o.in_idx)		;
 	jr	z,bg.wait
 
-	push	hl			;
-	push	ix
-	pop	hl
+	push	ix			;
+	ex	(sp),hl			;
 	add	a,l
 	ld	l,a
 	jr	nc,bg.nc
@@ -130,37 +129,27 @@ bg.nc:
 ; TODO: result code
 
 msg.recv:
-	push	de
-
-mr_wait_start:
 	call 	msg.in
 	cp	0AEh
-	jr	nz,mr_wait_start
-
+	jr	nz,msg.recv
 	call 	msg.in		; get message length
 	ld	c,a
 	inc	c
 	jr	mr_do
-
 mr_next:
-	dec	c
-	jr	z,mr_exit	; while chars in input buffer
+	dec	c		; while chars in input buffer
+	ret	z
 	call 	msg.in		;    get next
 mr_do:
-	ld	e,a
-	ld	a,b
-	or	a		;    if room in output buffer
-	jr	z,mr_skip
-	ld	(hl),e		;       store char
-	inc	hl
 	dec	b
-mr_skip:
+	jp	p,mr_store
+	inc	b
+	jr	mr_next
+mr_store:
+	ld	(hl),a		;       store char
+	inc	hl
 	jr	mr_next		;
 
-mr_exit:
-	pop	de
-	ret
-
 ;--------------------------------------------------------------
 
 msgo.st:
@@ -185,10 +174,9 @@ msg.out:
 	push	ix
 	ld	ix,(fifolst+itx)		;
 
-	push	hl			;
 	push	bc
 	push	ix
-	pop	hl
+	ex	(sp),hl			;
 	ld	c,(ix+o.in_idx)		;
 	ld	b,0
 	add	hl,bc
@@ -205,8 +193,8 @@ bp.wait:
 
 	ld	a,b
 	out	(AVRINT5),a
-	pop	bc
 	pop	hl
+	pop	bc
 	pop	ix
 	ret
 
@@ -330,7 +318,7 @@ msg.sout:
 	ld	b,(hl)			; 6
 	inc	hl			; 4
 	ex	de,hl			; 3
-ms.ol:					;	\
+ms.ol:					;
 	push	ix			;14
 	pop	hl			; 9
 	ld	c,(ix+o.in_idx)		;14
@@ -392,17 +380,19 @@ msnd_l:
 
 buf.put:
 	push	ix			;15
-	push	bc			;11
+	ex	(sp),hl			;16
 	ld	a,(ix+o.in_idx)		;19
-	ld	c,a			;4
-	ld	b,0			;7
-	add	ix,bc			;11
-	pop	bc			;10
-	ld	(ix),c			;7
-	pop	ix			;14
+	add	a,l			; 4
+	ld	l,a			; 4
+	jr	nc,bufp.1		;12/7
+	inc	h			; 4
+bufp.1:
+	ld	(hl),c			; 7
+	pop	hl			;10
 
+	ld	a,(ix+o.in_idx)		;19
 	inc	a			;4
-	and	(ix+o.mask)		;19	=121
+	and	(ix+o.mask)		;19	=129
 bufp.wait:
 	cp	(ix+o.out_idx)		;19
 	jr	z,bufp.wait		;12/7
@@ -410,8 +400,7 @@ bufp.wait:
 
 	out	(AVRINT5),a		;11
 	ld	a,c			;4
-	ret				;10	=191
-
+	ret				;10	=199
 
 ;----------------------------------------------------------------------
 ; Send message MEMORY
-- 
2.39.2