mirror of https://github.com/A2osX/A2osX.git
89 lines
2.2 KiB
Plaintext
89 lines
2.2 KiB
Plaintext
NEW
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AUTO 3,1
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* object code = ram_2
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* /RAM driver (main bank portion)
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* origin = $FF00
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RAMDRV cld no decimal.
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ldx #$0B save 13 bytes of parms
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.1 lda A1L,x
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sta a1l1,x
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dex
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bpl .1
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ldx #$01
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.2 lda passit,x save xfer vectors
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sta sp1,x
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dex
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bpl .2
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lda A4L get command.
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beq stat 0 = status
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cmp #$04 check for command too high.
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bcs ioerr if it is, i/o error
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eor #$03
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sta A4L 0=format, 2=read, 1=write
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beq format
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ldy bloknml+1 check for large block number.
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bne ioerr too big.
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lda bloknml block #
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bmi ioerr largest block number is $7F
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* at this point, control is passed to the code in the alternate 64k.
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* it it used for read, write and format. after the request is completed,
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* control is passed back to 'noerr'.
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format lda #RAMXDRV card entry point
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sta passit
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lda /RAMXDRV
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gocard sta passit+1 also used by 'mainwrt'
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sec direction ram -> card
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clv start with original zero page
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jmp xfer transfer control
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ioerr lda #$27
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bne H2D41
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lda #$2B write protect error.
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H2D41 sec flags error
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bcs H2D47
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noerr .EQ *
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stat lda #$00
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clc
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H2D47 php save status
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pha and error code.
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ldx #$0B restore 13 byes of parms
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H2D4B lda a1l1,x
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sta A1L,x
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dex
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bpl H2D4B
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lda sp1 restore xfer parms.
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bit $6060 addr $FF58 must = rts ($60) as in ROM
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sta passit
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lda sp1+1
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sta passit+1
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pla restore error code
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plp and status.
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rts
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mainwrt sta SETWRITEAUX write to alt 48K
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ldy #$00
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H2D6A lda (A1L),y pointers set in card by 'setptr'
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sta (A4L),y
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lda (A2L),y
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sta (A3L),y
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dey
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bne H2D6A
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sta CLRWRITEAUX write to main 48K.
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lda #donewrt done writing card
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sta passit
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lda /donewrt
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jmp gocard
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sp1 .HS 0000
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a1l1 .BS 13 13 bytes of storage
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* end of obj ram_2
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RAMDRV.END .EQ *
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.BS $FF9B-* fill to lanirq ($FF9B see note below)
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*--------------------------------------
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MAN
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SAVE usr/src/prodos.203/prodos.s.ram
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LOAD usr/src/prodos.203/prodos.s
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ASM
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