From 7e4f4505e544aaefc0fb3f6d9cd50fcdffc6f677 Mon Sep 17 00:00:00 2001
From: Joshua Wise <joshua@rebirth.joshuawise.com>
Date: Mon, 7 Apr 2008 02:50:15 -0400
Subject: [PATCH 1/1] Don't print A until we have to.

---
 diag.asm | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/diag.asm b/diag.asm
index 28fce99..786052e 100644
--- a/diag.asm
+++ b/diag.asm
@@ -13,7 +13,8 @@ main:
 
 	ld hl, $DF81
 	xor a
-	ld [hl], a
+	ld [hli], a
+	ld [hli], a
 	
 	ld hl, signon
 	call puts
@@ -44,10 +45,13 @@ irqhand:
 	ld c, $0F	; ack the irq
 	ld [c], a
 	
+	ld hl, $DF82
+	ld a, [hld]
+	cp 0
+	jr z, .noprint
 	ld a, $41	; print A
 	call putc
-	
-	ld hl, $DF81
+.noprint:
 	ld a, [hl]
 	add 1
 	ld c, $51
@@ -138,6 +142,10 @@ puthex:				; Put two hex nibbles to the serial console.
 waitsw:
 	ld hl,waitswstr
 	call puts
+	
+	ld hl,$DF82
+	ld a, 1
+	ld [hl], a
 
 	ld c, $51
 	xor a
-- 
2.43.0