mode7_demo: fix interrupt bug on older (pre IIe-enhanced) systems

mode7_demo/Makefile

@@ -9,12 +9,17 @@ all:	mode7_demo.dsk
 $(DOS33):	
 	cd ../dos33fs-utils && make
 
-mode7_demo.dsk:	$(DOS33) MODE7_DEMO MODE7_DEMO_C
+mode7_demo.dsk:	$(DOS33) MODE7_DEMO MODE7_DEMO_C HELLO
 #	$(DOS33) -y mode7_demo.dsk BSAVE -a 0x4000 MODE7_DEMO
 	$(DOS33) -y mode7_demo.dsk BSAVE -a 0x2000 MODE7_DEMO_C
+	$(DOS33) -y mode7_demo.dsk SAVE A HELLO
 
 
 
+####
+HELLO:	hello.bas
+	../asoft_basic-utils/tokenize_asoft < hello.bas > HELLO
+
 ###
 
 MODE7_DEMO_C:	mode7_decompress.o

mode7_demo/hello.bas

@@ -0,0 +1,10 @@
+   2  HOME 
+   5  PRINT 
+  10  PRINT "MODE7_DEMO V1.1"
+  20  PRINT 
+  23  PRINT 
+  24  PRINT "WWW.DEATER.NET/WEAVE/VMWPROD/MODE7_DEMO"
+  25  PRINT : PRINT 
+  30  FOR I = 1 TO 1000: NEXT I
+  40  HGR 
+  50  PRINT  CHR$ (4);"BRUN MODE7_DEMO_C"

mode7_demo/interrupt_handler.s

@@ -27,9 +27,17 @@
 CHUNKSIZE	EQU     11	; hardcoded, based on krg file
 
 interrupt_handler:
-	pha			; save A				; 3
+;	pha			; save A				; 3
+	; instead count on the handler saving A to $45
+
 				; Should we save X and Y too?
 
+	txa
+	pha			; Save X
+	tya
+	pha			; Save Y
+
+
 ;	inc	$0404		; debug (flashes char onscreen)
 
 	bit	$C404		; clear 6522 interrupt by reading T1C-L	; 4
@@ -278,7 +286,16 @@ done_interrupt:
 
 exit_interrupt:
 
-	pla			; restore a				; 4
+	pla
+	tay
+	pla
+	tax
+
+
+;	pla			; restore a				; 4
+
+	lda	$45		; restore A
+
 
 	rti			; return from interrupt			; 6
 

mode7_demo/mode7_demo.s

@@ -324,7 +324,9 @@ title_routine:
 .include "mockingboard.s"
 .include "credits.s"
 .include "interrupt_handler.s"
-.byte 0,0,0,0,0,0,0,0
+;.byte 0,0,0,0,0,0,0,0
+;.byte 0,0,0,0,0,0,0,0			; irq handler fix = +8 in size
+
 .byte 0,0,0,0,0,0,0,0
 .byte 0,0,0,0,0,0,0,0
 .byte 0,0,0,0