mirror of
https://github.com/deater/dos33fsprogs.git
synced 2024-12-29 00:31:52 +00:00
3089f8a840
was a hack to make displaying change disk message easier but now it's super easy to confuse BCD vs BIN for disk number
215 lines
3.1 KiB
ArmAsm
215 lines
3.1 KiB
ArmAsm
qload_hd:
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; set up prodos entry
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lda UNIT ;
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ldy #0
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setup_loop:
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lsr
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lsr
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lsr
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lsr
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and #7
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ora #$c0
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sta slot_smc+2
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sta entry_smc+2 ; set up smartport/prodos entry point
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slot_smc:
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lda $cfff
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sta entry_smc+1 ; set up rest of smartport/prodos entry
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; init the write code if needed
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; ???
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; first time entry
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lda #1
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sta NEW_GAME
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lda #0
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sta CURRENT_DISK
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; load the QLOAD offsets file to $1200
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jsr load_qload_offsets
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lda QLOAD_DISK_BIN ; get disk number (binary)
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sta CURRENT_DISK
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lda #0 ; load title, always 0th
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sta WHICH_LOAD
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main_game_loop:
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jsr load_file
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entry_point_smc:
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jsr $4000 ; most entry points currently $4000
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; CHECK LEVEL_OVER
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; if high bit set, jump to change_disk
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lda LEVEL_OVER
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bmi change_disk
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jmp main_game_loop
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;====================================
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; loads file specified by WHICH_LOAD
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;====================================
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load_file:
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ldx WHICH_LOAD
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lda LOAD_ADDRESS_ARRAY,X
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sta ADRHI
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sta entry_point_smc+2
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lda CURRENT_DISK
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sta BLOKHI
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inc BLOKHI ; off by one
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lda TRACK_ARRAY,X ; track
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asl
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asl
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asl
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rol BLOKHI
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sta BLOKLO
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lda SECTOR_ARRAY,X ; sector
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lsr
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clc
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adc BLOKLO
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sta BLOKLO
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lda LENGTH_ARRAY,X
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clc
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adc #1
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lsr ; important! blocks=sectors/2
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; need to round up if it was odd
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; careful: this could over-write if not careful
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sta COUNT
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jsr seekread
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rts ; todo: tail call
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;===================================================
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;===================================================
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; change disk
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;===================================================
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;===================================================
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; LEVEL_OVER bottom 4 bits hold which exit
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change_disk:
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lda LEVEL_OVER
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and #$f
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sta LEVEL_OVER
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tax
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; set up locations
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lda DISK_EXIT_DISK,X
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sta CURRENT_DISK
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lda DISK_EXIT_LOAD,X
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sta WHICH_LOAD
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lda DISK_EXIT_LEVEL,X
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sta LOCATION
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lda DISK_EXIT_DIRECTION,X
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sta DIRECTION
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lda DISK_EXIT_DNI_H,X
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sta NUMBER_HIGH
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lda DISK_EXIT_DNI_L,X
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sta NUMBER_LOW
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; see if disk we want is in drive
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;==========================
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; load QLOAD table
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; check if disk matches
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verify_disk:
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jsr load_qload_offsets
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;==============================================
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; all good, continue
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update_disk:
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jmp main_game_loop
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load_qload_offsets:
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lda #$12
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sta ADRHI
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lda CURRENT_DISK
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sta BLOKHI
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inc BLOKHI ; off by one
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lda #0 ; track
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asl
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asl
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asl
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rol BLOKHI
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sta BLOKLO
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lda #$2 ; sector
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lsr
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clc
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adc BLOKLO
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sta BLOKLO
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; lda #$0
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; sta load_track
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; lda #$02 ; track 0 sector 2
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; sta load_sector
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lda #$1
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sta COUNT
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jmp seekread
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;================================
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; seek + read blocks
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;================================
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; this calls the smartport PRODOS entrypoint
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; command=1 READBLOCK
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; I can't find this documented anywhere
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; but the paramaters are stored in the zero page
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;================================
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; BLOKHI:BLOKLO = block number to load (???)
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; COUNT = num blocks
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seekread:
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seekread_loop:
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lda #1 ; READBLOCK
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sta COMMAND
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lda ADRHI
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pha
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entry_smc:
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jsr $d1d1
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pla
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sta ADRHI
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inc ADRHI ; twice, as 512 byte chunks
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inc ADRHI
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inc BLOKLO ; increment block pointer
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bne no_blokloflo
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inc BLOKHI
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no_blokloflo:
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dec COUNT
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bne seekread_loop
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rts
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