rom4x/rom4x/B1_E300_new_bootfail.s

#include "iic.defs"
.text
* = nbtfail
	ldx #msglen
lp1	lda bootmsg,x
	ora #$80
	sta $7d0+19-msglen/2,x
	dex
	bpl lp1
	lda #23		; last line
	sta cv
	lda #>(basic-1)
	pha
	lda #<(basic-1)
	pha
	jmp swrts2
bootmsg	.db "No bootable device."
msglen = * - bootmsg - 1
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`
			`* = nbtfail`
			`ldx #msglen`
			`lp1 lda bootmsg,x`
			`ora #$80`
			`sta $7d0+19-msglen/2,x`
			`dex`
			`bpl lp1`
			`lda #23 ; last line`
			`sta cv`
			`lda #>(basic-1)`
			`pha`
			`lda #<(basic-1)`
			`pha`
			`jmp swrts2`
			`bootmsg .db "No bootable device."`
			`msglen = * - bootmsg - 1`