mirror of https://github.com/cc65/cc65.git
96 lines
2.3 KiB
ArmAsm
96 lines
2.3 KiB
ArmAsm
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; Oliver Schmidt, 31.03.2005
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;
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; unsigned __fastcall__ dio_query_sectcount (dhandle_t handle);
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;
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.export _dio_query_sectcount
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.import _dio_query_sectsize, _malloc, _free
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.include "zeropage.inc"
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.include "errno.inc"
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.include "mli.inc"
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_dio_query_sectcount:
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; Set handle
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sta mliparam + MLI::ON_LINE::UNIT_NUM
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; Get ProDOS 8 block size (clears ___oserror)
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jsr _dio_query_sectsize
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; Alloc buffer
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jsr _malloc
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sta ptr4
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stx ptr4+1
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; Set buffer
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sta mliparam + MLI::ON_LINE::DATA_BUFFER
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stx mliparam + MLI::ON_LINE::DATA_BUFFER+1
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; Check buffer (hibyte is enough)
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txa
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beq nomem
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; Get device state
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lda #ON_LINE_CALL
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ldx #ON_LINE_COUNT
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jsr callmli
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bcs check
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; UNIT_NUM already set
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.assert MLI::RW_BLOCK::UNIT_NUM = MLI::ON_LINE::UNIT_NUM, error
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; DATA_BUFFER already set
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.assert MLI::RW_BLOCK::DATA_BUFFER = MLI::ON_LINE::DATA_BUFFER, error
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; Read volume directory key block
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tax ; A = 0
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lda #$02
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sta mliparam + MLI::RW_BLOCK::BLOCK_NUM
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stx mliparam + MLI::RW_BLOCK::BLOCK_NUM+1
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lda #READ_BLOCK_CALL
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ldx #RW_BLOCK_COUNT
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jsr callmli
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bcs oserr
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; Get and save total blocks from volume directory header
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ldy #$29
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lda (ptr4),y
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pha
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iny
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lda (ptr4),y
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pha
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; Cleanup buffer
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done: lda ptr4
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ldx ptr4+1
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jsr _free
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; Restore total blocks and return
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pla
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tax
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pla
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rts
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nomem: lda #$FF ; Error code for sure not used by MLI
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oserr: sta ___oserror
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; Save total blocks for failure
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lda #$00
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pha
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pha
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beq done ; Branch always
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; Check for non-ProDOS disk
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check: cmp #$52 ; "Not a ProDOS volume"
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bne oserr
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sta ___oserror
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; Save total blocks for a 16-sector disk
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lda #<280
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pha
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lda #>280
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pha
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bne done ; Branch always
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