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Small updates for photon's bootloader

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This commit is contained in:
alpine9000
2016-03-19 13:04:44 +11:00
parent 908613627b
commit 450802d39f
2 changed files with 18 additions and 16 deletions
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3
Makefile
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@ -23,7 +23,8 @@ SUBDIRS=tools/makeadf \
018.vert_scroll\
019.hori_scroll\
020.shrinkler\
021.calling_c
021.calling_c\
022.photons_bootloader
.PHONY: subdirs $(SUBDIRS)

31
shared/hardware_bootblock.s
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@ -104,7 +104,7 @@ LoadScript: ;At $120, sysinfo in 4 regs, a6=$dff002
moveq #2,d0 ;from sector 2
move.w #-((mainEnd-mainStart)/512),d1;num sectors, - == Step0
jsr LoadMFMB
lea $dff000,a6 ;restore plain custombase addr for demo
lea $dff000,a6 ;restore plain custombase addr for demo
if SHRINKLER == 0
@ -171,7 +171,7 @@ LoadMFMB: ;loadsectors.a0=dst,d0=startsec.W,d1=nrsecs.W(-=Step0)
not.w d0 ;=neg+sub#1
.StOut: bsr.s StepOut
dbf d0,.StIn
.StRdy: swap d0 ;startsec within cyl
.StRdy: swap d0 ;startsec within cyl
cmp.w #11,d0
blt.s .Head0
sub.w #11,d0
@ -179,12 +179,12 @@ LoadMFMB: ;loadsectors.a0=dst,d0=startsec.W,d1=nrsecs.W(-=Step0)
.Head0: bset #2,(a4)
lea MFMhead(PC),a1
clr.w (a1)
bsr LoadTrak ;read track+decode
bsr LoadTrak ;read track+decode
beq.s .End
.Head1: bclr #2,(a4) ;Head 1
lea MFMhead(PC),a1
move.w #1,(a1)
bsr LoadTrak ;read track+decode
bsr LoadTrak ;read track+decode
beq.s .End
bsr.s StepIn ;1 cyl forward
bra.s .Head0
@ -253,12 +253,12 @@ LoadTrak: ;loadtrack+decode.a0=dst,d0=secoffs,d1=secsleft
lea (MFMbuf).w,a1
move.w #2,$9c-2(a6) ;Clr Req
move.l a1,$20-2(a6)
move.w #$8210,$96-2(a6) ;DskEna
move.w #$8210,$96-2(a6) ;DskEna
move.w #MFMsync,$7e-2(a6)
move.w #$9500,$9e-2(a6)
move.w #$4000,$24-2(a6)
move.w #$8000+MFMlen/2,$24-2(a6) ;DskLen(12980)+DmaEn
move.w #$8000+MFMlen/2,$24-2(a6) ;start reading MFMdata
move.w #$8000+MFMlen/2,$24-2(a6);DskLen(12980)+DmaEn
move.w #$8000+MFMlen/2,$24-2(a6);start reading MFMdata
.Wrdy:
btst #1,$1f-2(a6) ;wait until data read
beq.s .Wrdy
@ -275,7 +275,7 @@ LoadTrak: ;loadtrack+decode.a0=dst,d0=secoffs,d1=secsleft
bne.s .FindS
cmp.b (a1),d3 ;search for 0-nibble
bne.s .FindS
move.l (a1)+,d4 ;decode fmtbyte/trk#,sec#,eow#
move.l (a1)+,d4 ;decode fmtbyte/trk#,sec#,eow#
move.l (a1)+,d5
and.w d3,d4
and.w d3,d5
@ -288,12 +288,12 @@ LoadTrak: ;loadtrack+decode.a0=dst,d0=secoffs,d1=secsleft
blt.s .DeCode
.Skip: lea 48+1024(a1),a1 ;nope
bra.s .FindS
.DeCode:lea 40(a1),a1 ;found a sec,skip unnecessary data
.DeCode:lea 40(a1),a1 ;found a sec,skip unnecessary data
move.l a1,d6
lea MFMchk(PC),a1
clr.l (a1)
move.l d6,a1
move.l (a1)+,d6 ;decode data chksum.L
move.l (a1)+,d6 ;decode data chksum.L
move.l (a1)+,d5
and.l d3,d6
and.l d3,d5
@ -313,15 +313,15 @@ LoadTrak: ;loadtrack+decode.a0=dst,d0=secoffs,d1=secsleft
add.l d4,d4
or.l d5,d4
move.l d4,(a3)+
dbf d7,.DClup ;chksum should now be 0 if correct
dbf d7,.DClup ;chksum should now be 0 if correct
lea MFMchk(PC),a1
or.l d6,(a1) ;or with track total chksum
move.l a2,a1
dbf d1,.FindS ;decode next sec
dbf d1,.FindS ;decode next sec
MOVE.W (SP)+,D1
MOVE.W (SP)+,D0
move.l MFMchk(PC),d3 ;track total chksum OK?
bne LoadTrak ;no,retry
bne LoadTrak ;no,retry
moveq #0,d0 ;set to start of track
move.w d2,d3
add.w d3,d3
@ -333,7 +333,7 @@ LoadTrak: ;loadtrack+decode.a0=dst,d0=secoffs,d1=secsleft
NullCop:
dc.w $1fc,0
dc.w $100,$0200
dc.w $96,$0020 ;ensure sprite DMA is off until needed
dc.w $96,$0020 ;ensure sprite DMA is off until needed
dc.w $ffdf,$fffe
dc.l -2
@ -344,7 +344,8 @@ BootE:
*** Boot Block ends here ***
dc.b "BootLoader by Photon/Scoopex" ;pad with random bytes
dc.b "BootLoader by Photon/Scoopex"
;pad bootblock to correct size
cnop 0,1024
;MFMbuf is placed here after bootblock end, $3c0.w or so when copied.