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kickstart.a65
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; C65GS Kick Start ROM.
; Paul Gardner-Stephen, 2014-2015.
;
; Purpose:
; 1. Verify checksum of ROM area of slow RAM.
; 1. If checksum fails, load complete ROM from SD card.
; 2. Select default disk image for F011 emulation.
;
; The kickstart ROM is 16KB in length, and maps at $8000-$BFFF
; in hypervisor mode.
;
; Kickstart modifies RAM from $0000-$07FF (ZP, stack, 40-column
; screen) during normal boot.
;
; If Kickstart needs to load the ROM from SD card, then it may
; modify the first 64KB of fast ram.
;
; We will use the convention of C=0 means failure, and C=1 means
; success.
;
.include "kickstart_machine.a65"
; scratch space in ZP space usually used by kernel
; we try to use address space not normally used by C64 kernel, so that
; it is possible to make calls to kickstart after boot. Eventually
; the desire is to have an SYS call that brings up a menu that lets
; you choose a disk image from a list.
.data
.org $ce00
.space romslab 1
.space screenrow 1
.space checksum 4
.space file_pagesread 2
; variables for testing of D81 boot image
.space d81_clusternumber 4
.space d81_clustersneeded 2
.space d81_clustercount 2
; make sure that we don't go past the 256 byte page reserved for hypervisor scratch space
.checkpc $CEFF
.text
.org $8000
;;; ----------------------------------------------------------------------------
;;; CPU Hypervisor Trap entry points.
;;; 64 x 4 byte entries for user-land traps.
;;; some more x 4 byte entries for system traps (reset, page fault etc)
;;; ----------------------------------------------------------------------------
trap_entry_points:
; Traps $00-$07 (user callable)
jmp dos_and_process_trap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
; Traps $08-$0F (user callable)
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
; Traps $10-$17 (user callable)
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
; Traps $18-$1F (user callable)
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
; Traps $20-$27 (user callable)
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
; Traps $28-$2F (user callable)
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
; Traps $30-$37
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
; Traps $38-$3F (user callable)
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
; Traps $40-$4F (reset, page fault and other system-generated traps)
jmp reset_entry_allow_etherkick ; Trap #$40 (power on / reset)
nop
jmp page_fault ; Trap #$41 (page fault)
nop
jmp nosuchtrap ; Trap #$42 (double-tap RESTORE key)
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
jmp nosuchtrap
nop
; Leave room for traps to $7F
.advance $8200
;;; ----------------------------------------------------------------------------
;;; Etherkick / kickup utility functions
;;; ----------------------------------------------------------------------------
; We place a small routine at precisely $8200 that allows etherkick to reset
; kickstart, without it allowing etherkick mode until reset. This allows the
; etherkick process to update kickstart, and then start it normally, without
; requiring the operator to fiddle any switches.
jmp reset_entry_no_etherkick
;;; ----------------------------------------------------------------------------
;;; Hypervisor traps
;;; ----------------------------------------------------------------------------
;;; ----------------------------------------------------------------------------
;;; Illegal trap / trap sub-function handlers
;;; ----------------------------------------------------------------------------
; Traps are triggered by writing to $D640-$D67F
; and trap to $8000+((address & $3F)*4) in the hypervisor
; Routine for unimplemented/reserved traps
; (Consider replacing with trap to hypervisor error screen with option
; to return?)
nosuchtrap:
; Clear C flag for caller to indicate failure
lda hypervisor_flags
and #$FE ; C flag is bit 0
sta hypervisor_flags
; set A to $FF
lda #$ff
sta hypervisor_a
; return from hypervisor
sta hypervisor_enterexit_trigger
; Return from trap with C flag clear to indicate success
return_from_trap_with_success:
; set C flag for caller to indicate success
lda hypervisor_flags
ora #$01 ; C flag is bit 0
sta hypervisor_flags
; return from hypervisor
sta hypervisor_enterexit_trigger
return_from_trap_with_failure:
; report error in A
sta hypervisor_a
lda hypervisor_flags
ora #$01 ; C flag is bit 0
sta hypervisor_flags
; return from hypervisor
sta hypervisor_enterexit_trigger
invalid_subfunction:
jmp nosuchtrap
;;; ----------------------------------------------------------------------------
;;; DOS, process control and related functions trap
;;; ----------------------------------------------------------------------------
.include "kickstart_dos.a65"
;;; ----------------------------------------------------------------------------
;;; Virtual memory and memory management
;;; ----------------------------------------------------------------------------
.include "kickstart_mem.a65"
;;; ----------------------------------------------------------------------------
;;; Task (process) management
;;; ----------------------------------------------------------------------------
.include "kickstart_task.a65"
;;; ----------------------------------------------------------------------------
;;; CPU Hypervisor Entry Point on reset
;;; ----------------------------------------------------------------------------
reset_machine_state:
; get CPU state sensible
sei
cld
see
; sprites off
lda #$00
sta $d017
lda #$7f
sta $DC0D
sta $DD0D
lda #$00
sta $D01A
; We DO NOT need to mess with $01, because
; the 4510 starts up with kickstart mapped at $8000-$BFFF
; enhanced ($FFD3xxx) IO page mapped at $D000,
; and fast RAM elsewhere.
; disable IRQ sources
lda #$7f
sta $DC0D
sta $DD0D
LDA #$00
STA $D019
sec
jsr enhanced_io
jsr resetdisplay
jsr erasescreen
jsr resetpalette
rts
;;; ----------------------------------------------------------------------------
;;; CPU Hypervisor reset/trap routines
;;; ----------------------------------------------------------------------------
reset_entry_allow_etherkick:
sei
lda #$00
sta kickstart_boot_flags
jmp reset_entry_common
reset_entry_no_etherkick:
sei
lda #$80
sta kickstart_boot_flags
jmp reset_entry_common
reset_entry_common:
jsr reset_machine_state
; display welcome screen
ldx #<msg_kickstart
ldy #>msg_kickstart
jsr printbanner
; leave a blank line below kickstart banner
ldx #<msg_blankline
ldy #>msg_blankline
jsr printmessage
; Display GIT commit
ldx #<msg_gitcommit
ldy #<msg_gitcommit
jsr printmessage
; check keyboard for 0-9 down to select alternate rom
jsr keyboardread
; If switch 8 and 9 are set, and etherkick mode is not disabled
; then wait forever for ethernet packets
lda kickstart_boot_flags
bmi normalboot
lda $d6f1
and #$02
beq normalboot
etherboot:
ldx #<msg_etherkick
ldy #>msg_etherkick
jsr printmessage
jsr setupethernet
etherloop:
jsr checkethernet
jmp etherloop
normalboot:
; Try to read the MBR from the SD card to ensure SD card is
; happy
ldx #<msg_tryingsdcard
ldy #>msg_tryingsdcard
jsr printmessage
tryreadmbr:
jsr readmbr
bcs gotmbr
jmp tryreadmbr
gotmbr:
; Scan SD card for partitions and mount them.
jsr dos_clearall
jsr dos_read_partitiontable
ldx #<msg_diskcount
ldy #>msg_diskcount
jsr printmessage
ldy #$00
ldz dos_disk_count
jsr printhex
; Go to root directory on default disk
ldx dos_default_disk
jsr dos_cdroot
bcs mountsystemdiskok
ldx #<msg_cdrootfailed
ldy #>msg_cdrootfailed
jsr printmessage
ldy #$00
ldz dos_error_code
jsr printhex
mountsystemdiskok:
; Load and display boot logo
; Prepare 32-bit pointer for loading boot logo @ $0004000
lda #$00
sta <dos_file_loadaddress+0
lda #$40
sta <dos_file_loadaddress+1
lda #$00
sta <dos_file_loadaddress+2
lda #$00
sta <dos_file_loadaddress+3
ldx #<txt_bootlogo
ldy #>txt_bootlogo
jsr dos_setname
jsr dos_readfileintomemory
bcs logook
ldx #<msg_nologo
ldy #>msg_nologo
jsr printmessage
ldy #$00
ldz dos_error_code
jsr printhex
logook:
; iterate through directory entries looking for ordinary file
; KICKUP.G65 to load into hypervisor memory ...
; ... but only if we are not running a kick-up'd kickstart now.
lda $d67e
beq nextdirectoryentry3
; already kicked
ldx #<msg_alreadykicked
ldy #>msg_alreadykicked
jsr printmessage
jmp postkickup
nextdirectoryentry3:
; Prepare 32-bit pointer for loading boot logo @ $0004000
lda #$00
sta <dos_file_loadaddress+0
lda #$40
sta <dos_file_loadaddress+1
lda #$00
sta <dos_file_loadaddress+2
lda #$00
sta <dos_file_loadaddress+3
ldx #<txt_kickupfile
ldy #>txt_kickupfile
jsr dos_setname
jsr dos_readfileintomemory
bcc nokickup
; We have loaded kickup file, so jump into it.
ldx #<msg_kickuploaded
ldy #>msg_kickuploaded
jsr printmessage
ldy #$00
ldz <zptempv32+3
jsr printhex
ldz <zptempv32+2
jsr printhex
ldz <zptempv32+1
jsr printhex
ldz <zptempv32+0
jsr printhex
; Use DMAgic to copy $0004000-$0007FFF to $FFF8000-$FFFBFFF
; (We have to copy the routine to do this to RAM, since we will
; be replacing ourselves)
ldx #$00
krc: lda kickuproutine,x
sta $3000,x
inx
bne krc
jmp $3000
kickuproutine:
; The following routine gets copied as-is to $3000 and run from there.
; The DMA list is still available in the kickstart ROM when it gets
; called, so we can just use it there, instead of working out where
; it gets copied to
; Set bottom 22 bits of DMA list address as for C65
; (8MB address range). Kickstart ROM is at $FFF8000, so $FF goes
; in high-byte area
lda #$ff
sta $d702
lda #$ff
sta $d704 ; dma list is in top MB of address space
sta $d706 ; similarly destination of copy is top MB of address space
lda #$00
sta $d705 ; source of copy is bottom MB of address space
lda #>kickupdmalist
sta $d701
lda #<kickupdmalist
sta $d700
; clear source/destination MB so that C65 ROM doesn't go bananas
lda #$00
sta $d706
; copy complete, so mark ourselves upgraded, and jump into hypervisor
; as though we were just reset.
sta $d67e ; mark ourselves as having kicked up
jmp $8100
kickupdmalist:
; copy $0004000-$0007FFF to $FFF8000-$FFFBFFF
; (MB offsets get set in routine)
.byte $00 ; copy + last request in chain
.word $4000 ; size of copy is 16KB
.word $4000 ; starting at $4000
.byte $00 ; of bank $0
.word $8000 ; destination address is $8000
.byte $0F ; of bank $F
.word $0000 ; modulo (unused)
couldntopenkickup:
nokickup:
ldx #<msg_nokickup
ldy #>msg_nokickup
jsr printmessage
postkickup:
; MILESTONE: Have file system properties.
; Look for C65GS.D81 to mount for F011 emulation
; for now indicate that there is no disk in drive
lda #$00
sta $d68b
jsr dos_cdroot
bcc sdcarderror
; set name of file we are looking for
ldx #<txt_c65gsd81
ldy #>txt_c65gsd81
jsr dos_setname
jsr dos_findfile
bcc nod81
jsr dos_closefile
; this is the entry
ldx #<msg_foundd81
ldy #>msg_foundd81
jsr printmessage
; now we need to check that the file is long enough,
; and also that the clusters are contiguous.
; Start by opening the file
jsr dos_set_current_file_from_dirent
bcc nod81
jsr dos_openfile
bcc nod81
; work out how many clusters we need
; We need 1600 sectors, so halve for every zero tail
; bit in sectors per cluster. we can do this because
; clusters in FAT must be 2^n sectors.
lda #$00
sta d81_clustercount
sta d81_clustercount+1
lda #<1600
sta d81_clustersneeded
lda #>1600
sta d81_clustersneeded+1
; get sectors per cluster of disk
ldx dos_disk_table_offset
lda dos_disk_table+fs_fat32_sectors_per_cluster,x
taz
l94: tza
and #$01
bne d81firstcluster
tza
lsr
taz
lsr d81_clustersneeded+1
ror d81_clustersneeded
jmp l94
d81firstcluster:
; Get current cluster of D81 file, so that
; we can check that clusters in file are contiguous
ldx dos_current_file_descriptor_offset
ldy #0
l94b: lda dos_file_descriptors+dos_filedescriptor_offset_currentcluster,x
sta d81_clusternumber,y
inx
iny
cpy #4
bne l94b
d81nextcluster:
; Now read through clusters and make sure that all is
; well.
; check that it matches expected cluster number
ldx dos_current_file_descriptor_offset
ldy #0
l94a: lda dos_file_descriptors+dos_filedescriptor_offset_currentcluster,x
cmp d81_clusternumber,y
bne d81isfragged
inx
iny
cpy #4
bne l94a
; increment number of clusters found so far
inc d81_clustercount
bne l96
inc d81_clustercount+1
l96:
; increment expected cluster number
clc
lda d81_clusternumber
adc #$01
sta d81_clusternumber
lda d81_clusternumber+1
adc #$00
sta d81_clusternumber+1
lda d81_clusternumber+2
adc #$00
sta d81_clusternumber+2
lda d81_clusternumber+3
adc #$00
sta d81_clusternumber+3
jsr dos_file_advance_to_next_cluster
bcs d81nextcluster
jsr dos_closefile
; read to end of D81 file, and it is contiguous
; now check that it is the right length
lda d81_clustersneeded
cmp d81_clustercount
bne d81wronglength
lda d81_clustersneeded+1
cmp d81_clustercount+1
bne d81wronglength
; D81 is good, so set flag
lda #$07
sta $d68b
ldx #<msg_d81mounted
ldy #>msg_d81mounted
jsr printmessage
; all done, move on to loading the ROM
jmp findrom
d81wronglength:
ldx #<msg_d81wronglength
ldy #>msg_d81wronglength
jsr printmessage
jmp findrom
d81isfragged:
ldx #<msg_d81fragged
ldy #>msg_d81fragged
jsr printmessage
jmp findrom
nod81:
; we couldn't find the D81 file, so tell the user
ldx #<msg_nod81
ldy #>msg_nod81
jsr printmessage
ldy #$00
ldz dos_error_code
jsr printhex
findrom:
; Check state of current ROM
jsr checkromok
bcc loadrom
; ROM is loaded and ready, so transfer control
; to it.
ldx #<msg_romok
ldy #>msg_romok
jsr printmessage
jmp go64
loadrom:
; ROM is not loaded, so try to load it, or prompt
; for user to insert SD card
ldx #<msg_rombad
ldy #>msg_rombad
jsr printmessage
; Load CHARROM.G65 into character ROM
ldx #<txt_c65gscharrom
ldy #>txt_c65gscharrom
jsr dos_setname
; Prepare 32-bit pointer for loading whole ROM ($FF7E000)
lda #$00
sta <dos_file_loadaddress+0
lda #$E0
sta <dos_file_loadaddress+1
lda #$F7
sta <dos_file_loadaddress+2
lda #$0F
sta <dos_file_loadaddress+3
jsr dos_readfileintomemory
bcs loadedcharromok
ldx #<msg_charrombad
ldy #>msg_charrombad
jsr printmessage
jmp loadc65rom
loadedcharromok:
ldx dos_current_file_descriptor_offset
lda dos_file_descriptors+dos_filedescriptor_offset_fileoffset+0,x
sta file_pagesread
lda dos_file_descriptors+dos_filedescriptor_offset_fileoffset+1,x
sta file_pagesread+1
ldx #<msg_charromloaded
ldy #>msg_charromloaded
jsr printmessage
ldy #$00
ldz file_pagesread+1
jsr printhex
ldz file_pagesread
jsr printhex
loadc65rom:
ldx #<txt_c65gsrom
ldy #>txt_c65gsrom
jsr dos_setname
; Prepare 32-bit pointer for loading whole ROM ($0020000)
lda #$00
sta <dos_file_loadaddress+0
sta <dos_file_loadaddress+1
sta <dos_file_loadaddress+3
lda #$02
sta <dos_file_loadaddress+2
jsr dos_readfileintomemory
bcs loadedok
; ROM not found: indicate which ROM we were looking for
ldx #$0b
l17d: lda txt_c65gsrom,x
sta msg_romnotfound+19,x
dex
bne l17d
ldx #<msg_romnotfound
ldy #>msg_romnotfound
jsr printmessage
jsr sdwaitawhile
jsr sdwaitawhile
jsr sdwaitawhile
jsr sdwaitawhile
jmp sdcarderror
loadedok:
ldx dos_current_file_descriptor_offset
lda dos_file_descriptors+dos_filedescriptor_offset_fileoffset+0,x
sta file_pagesread
lda dos_file_descriptors+dos_filedescriptor_offset_fileoffset+1,x
sta file_pagesread+1
lda file_pagesread
bne romfiletooshort
lda file_pagesread+1
cmp #$00
beq romfiletooshort
cmp #$02
bne romfiletoolong
; need to store checksum
jsr storeromsum
; ROM file loaded, transfer control
ldx #<msg_romok
ldy #>msg_romok
jsr printmessage
jmp go64
romfiletoolong:
ldx #<msg_romfilelongerror
ldy #>msg_romfilelongerror
jsr printmessage
ldz file_pagesread+1
jsr printhex
ldz file_pagesread
jsr printhex
jsr sdwaitawhile
jmp reset_entry_allow_etherkick
romfiletooshort:
ldx #<msg_romfileshorterror
ldy #>msg_romfileshorterror
jsr printmessage
ldz file_pagesread+1
jsr printhex
ldz file_pagesread
jsr printhex
jsr sdwaitawhile
jmp reset_entry_allow_etherkick
fileopenerror:
ldx #<msg_fileopenerror
ldy #>msg_fileopenerror
jsr printmessage
sdcarderror: ldx #<msg_sdcarderror
ldy #>msg_sdcarderror
jsr printmessage
jsr sdwaitawhile
jmp reset_entry_allow_etherkick
badfs: ldx #<msg_badformat
ldy #>msg_badformat
jsr printmessage
jsr sdwaitawhile
jmp reset_entry_allow_etherkick
;;; ----------------------------------------------------------------------------
;;; FAT file system routines
;;; ----------------------------------------------------------------------------
toupper: ; convert ASCII character to upper case
cmp #$60
bcc tu1
cmp #$7a
bcs tu1
and #$5f
tu1: rts
;;; ----------------------------------------------------------------------------
;;; MBP / partition routines
;;; ----------------------------------------------------------------------------
; read master boot record. Does not sanity check anything.
readmbr:
; begin by resetting SD card
jsr sdreset
bcs l7
rts
l7: ldx #<msg_foundsdcard
ldy #>msg_foundsdcard
jsr printmessage
; MBR is sector 0
lda #$00
sta $D681
sta $d682
sta $d683
sta $d684
jmp sd_readsector
;;; ----------------------------------------------------------------------------
;;; SD Card access routines
;;; ----------------------------------------------------------------------------
sdreset:
; try SD-HC mode first
; lda #$41
; sta $D680
; jsr sd_resetsequence
; bcc sdr1
; rts
sdr1: ; fall back to SD mode
lda #$42
sta $d680
; fall through
sd_resetsequence:
; write $00 to $D680 to start reset
lda #$00
sta $D680
jsr sdtimeoutreset
re1: jsr sdreadytest
bcs re1done ; success, so return
bne re1 ; not timed out, so keep trying
rts ; timeout, so return
re1done:
; write $01 to $D680 to complete reset
lda #$01
sta $D680
jsr sdtimeoutreset
re2: jsr sdreadytest
bcs re2done ; success, so return
bne re2 ; not timed out, so keep trying
rts ; timeout, so return
re2done:
; give card some time to settle after reset, otherwise
; reading sectors will fail
jsr sdwaitawhile
jsr sd_map_sectorbuffer
; write $02 to $D680 to read MBR as a test of reset
lda #$02
sta $D680
jsr sdtimeoutreset
re3: ; allow time for read to happen
lda $d680
jsr sdreadytest
bcs redone ; success, so return
bne re3 ; not timed out, so keep trying
; timeout -- so call reset again
rts
redone:
sec
rts
; Watch for ethernet packets while waiting for the SD card.
; this allows loading of code into the hypervisor for testing and
; bare-metal operation.
sdwaitawhile: jsr sdtimeoutreset
sw1:
inc $d020
jsr checkethernet
dec $d020
inc $0300
bne sw1
inc $0301
bne sw1
inc $0302
bne sw1
rts
; count to timeout value when trying to read from SD card
; (if it is too short, the SD card won't reset)
sdtimeoutreset:
lda #$00
sta $0300
sta $0301
lda #$f7
sta $0302
rts
sdreadytest: ; check if SD card is ready, or if timeout has occurred
; C is set if ready.
; Z is set if timeout has occurred.
lda $d680
and #$03
beq sdisready
inc $0300
bne sr1
inc $0301
bne sr1
inc $0302
bne sr1
; timeout
lda #$00 ; set Z
sr1: clc
rts
sdisready: sec
rts
sd_map_sectorbuffer:
lda #$81
sta $D680
sec
rts
sd_unmap_sectorbuffer:
lda #$82
sta $D680
sec
rts
sd_readsector: