From e9399116c75f3976baaf893648359ec13dd67de4 Mon Sep 17 00:00:00 2001
From: Martin Haye <martin.haye@ucop.edu>
Date: Tue, 2 Mar 2021 17:28:04 -0800
Subject: [PATCH] Test that AUX RAM is available; if not complain that 128K IIe
 or later is required.

---
 Platform/Apple/virtual/src/core/loader.s | 26 ++++++++++++++++++++----
 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/Platform/Apple/virtual/src/core/loader.s b/Platform/Apple/virtual/src/core/loader.s
index 0f393931..00791d30 100644
--- a/Platform/Apple/virtual/src/core/loader.s
+++ b/Platform/Apple/virtual/src/core/loader.s
@@ -38,15 +38,30 @@ init	; Put something interesting on the screen :)
 	jsr ROM_setkbd
 	jsr ROM_setvid
 	jsr ROM_home
-	ldy #0
++	; Test that we have AUX RAM (required)
+	sty pSrc
+	sta setAuxZP
+	iny
+	sty pSrc
+	cpy pSrc
+	sta clrAuxZP
+	bne +
+	cpy pSrc
+	bne ++
++	ldy #0
+-	lda .insuffText,y
+	beq -		; loop forever
+	jsr ROM_cout
+	iny
+	bne -
+	; Display welcome message
+++	ldy #0
 -	lda .welcomeText,y
 	beq +
 	jsr ROM_cout
 	iny
 	bne -
-	beq +
-.welcomeText: !text "Welcome to LegendOS.",$8D,0
-; Init pointer to blocks we're going to move/decompress
+	; Init pointer to blocks we're going to move/decompress
 +	lda #<dataStart
 	sta pData
 	lda #>dataStart
@@ -167,4 +182,7 @@ debug	jsr ROM_crout
 	jmp ROM_cout
 }
 
+.insuffText : !text "REQUIRES 128K IIE OR LATER.",0
+.welcomeText: !text "Welcome to LegendOS.",$8D,0
+
 dataStart = *
\ No newline at end of file