rom4x/rom4x/B0_C552_patch_bootfail.s

#include "iic.defs"

.text
* = $c552
	jsr setnorm
	jsr init
	bra cbtfail
	.dsb coma-*,$ea
	bra coma		; Make sure coma routine exists
	.db 0			; rom4x present
cbtfail	jsr setvid
	jsr setkbd
	lda #>(nbtfail-1)
	pha
	lda #<(nbtfail-1)
	pha
	jmp swrts2
Simplify bootable ramdisk detection. Jump to AppleSoft if no boot device. I discovered that there are more than one ProDOS boot block in the wild, so I simplified the check for recoverable RAM disk to check card for $01 and then anything besides $00 and $FF since most uninitialized RAM tends to have one of those two values. This is slightly more rigid than the boot code checks for. I added a jump to AppleSoft if no bootable device is found. I changed the message a little bit, too. I also added notes about the feasibility of using the RamFactor firmware. 2017-01-13 03:40:55 +00:00			`#include "iic.defs"`

			`.text`
			`* = $c552`
			`jsr setnorm`
			`jsr init`
			`bra cbtfail`
			`.dsb coma-*,$ea`
			`bra coma ; Make sure coma routine exists`
			`.db 0 ; rom4x present`
			`cbtfail jsr setvid`
			`jsr setkbd`
			`lda #>(nbtfail-1)`
			`pha`
			`lda #<(nbtfail-1)`
			`pha`
			`jmp swrts2`