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rom4x
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add block counter safety check to config finder

This commit is contained in:
mgcaret 2017-05-27 17:08:08 -07:00
parent fdbb458ec6
commit ea801bed1f
1 changed files with 55 additions and 48 deletions
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29
rom4x/B1_E000_rom4x.s
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@ -92,30 +92,33 @@ msg1 = *
.byte $04,$2e,"6 Boot Int. 5.25"
.byte $04,$ae,"7 Boot Ext. 5.25"
.byte $07,$5f,"By M.G."
msg2: .byte $07,$db,"ROM 4X 04/08/17"
msg2: .byte $07,$db,"ROM 4X 05/27/17"
.byte $05,$ae,$00 ; cursor pos in menu
msg3: .byte $05,$b0,"SURE? ",$00
; Boot4X - the boot portion of the program
.assert * < boot4x, warning, .sprintf("Boot4X overrun! * = %x, > %x", *, boot4x)
.res boot4x - *, 0
.org boot4x
jsr gobanner ; "Apple //c"
jsr rdrecov ; try to recover ramdisk
lda power2 + rx_mslot ; get action saved by reset4x
beq :+
beq :+ ; unset, go look for config on ram card
pha ; save it
bra selboot ; set, go do it
: lda numbanks,y ; (y should be OK here) ram card present?
bra selboot ; now go do it
: lda numbanks,y ; (y should be set in rdrecov) ram card present?
beq boot6 ; nope, boot slot 6
jsr getcfg ; try to get config
bcs boot4 ; no config, normal boot
;stx $7d2
;sty $7d3
phx ; config present, move on
phx ; config present, save it and move on
lda #'C' ; tell user
sta $7d1 ; on screen
selboot: ldx #(msg2-msg1) ; short banner offset
jsr disp ; display it
pla ; boot selection
sta $7d2
pla ; get boot selection from stack
;sta $7d2
btc2: cmp #$02 ; clear ramcard
bne btc3
jsr rdclear ; do clear
@ -231,10 +234,11 @@ bt4xend = *
chktype = $06 ; 'BIN' - easy to set auxtype with bsave
entbuf = $0280
; zp locs, safe to use under our circumstances
blkptrl = $06
blkptrl = $06 ; block we are going to read
blkptrh = blkptrl + 1
entryl = $08
nentries = $09
entryl = $08 ; length of an entry
nentries = $09 ; number of entries per block
blkcnt = $0a ; block counter for safety
.proc getcfg
jsr rdinit
lda #$02 ; first block of volume directory
@ -255,7 +259,8 @@ bt4xend = *
cmp #$f0 ; storage type is $f?
bne nocfg ; nope, eom
lda #$23 ; offset of directory entry length in block
sta addrl,x
sta blkcnt ; may as well use this for the safety check
sta addrl,x ; set data pointer
lda data,x ; grab entry length
sta entryl ; save it
ldy data,x ; entries per block
@ -263,6 +268,8 @@ bt4xend = *
bra nxtbl1 ; skip setting slinky block and nentries, already there
nxtblk: jsr setblk
beq nocfg ; just set block 0, eom
dec blkcnt ; decrease safety counter
beq nocfg ; and if we hit zero, bail out
ldy nentries ; restore # entries per block+1 into y
nxtbl1: jsr gnxtblk ; set next block pointer, leave data ptr at offset $04
nxtent: dey ; next entry, assumes y has # of entries remaining to check