Check ROM is valid before loading.

projects/library/check-rom.tal

@@ -0,0 +1,15 @@
+@check-rom ( filename* -- 00 if the file doesn't exist or not a valid ROM
+                       OR 01 if the ROM seems to be valid )
+	.File/name DEO2
+	#0001 .File/length DEO2
+	;&first-char .File/read DEO2
+
+	( did the file read okay? )
+	.File/success DEI2 ORA
+
+	( is the first character a LIT, LIT2, LITk or LIT2k? )
+	LIT &first-char $1 #9f AND #80 EQU
+
+	AND
+	JMP2r
+

projects/library/load-rom.tal

@@ -12,14 +12,6 @@
 
 	.File/name DEO2
 
-	( return if file can't be found, or zero length )
-	#0001 .File/length DEO2
-	;&tmp .File/read DEO2
-	.File/success DEI2 ORA JMP JMP2r
-
-	( close the file so the next read starts at the beginning )
-	.File/name DEI2k ROT DEO2
-
 	( clear wst )
 	#ab
 	&wst-loop

projects/software/boot.tal

@@ -182,6 +182,11 @@ RTN
 	DUP2 INC2 ;close-path JSR2
 	#0006 ++ DUP2 ;print-string JSR2
 	#0a .Console/write DEO
+
+	DUP2 ;check-rom JSR2 ,&valid JCN
+	POP2 RTN
+
+	&valid
 	;load-rom JSR2
 
 RTN
@@ -394,6 +399,7 @@ RTN
 	2729 2b2e 3032 3537 3a3d 3f42 4547 4a4d
 	5053 5659 5c5f 6265 686b 6e71 7477 7a7d
 
+include projects/library/check-rom.tal
 include projects/library/load-rom.tal
 
 include projects/assets/logo05x05.tal