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48 lines
1.0 KiB
ArmAsm
48 lines
1.0 KiB
ArmAsm
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; Ullrich von Bassewitz, 17.11.2002
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; Common stuff for the read/write routines
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;
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.export rwcommon
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.import popax
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.importzp ptr1, ptr2, ptr3, tmp2
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.include "filedes.inc"
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;--------------------------------------------------------------------------
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; rwcommon: Pop the parameters from stack, preprocess them and place them
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; into zero page locations. Return carry set if the handle is invalid,
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; return carry clear if it is ok. If the carry is clear, the handle is
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; returned in A.
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.proc rwcommon
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jsr popax ; Get count
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eor #$FF
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sta ptr1
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txa
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eor #$FF
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sta ptr1+1 ; Remember -count-1
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jsr popax ; Get buf
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sta ptr2
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stx ptr2+1
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lda #$00
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sta ptr3
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sta ptr3+1 ; Clear ptr3
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jsr popax ; Get the handle
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sta tmp2
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cpx #$01
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bcs inv
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cmp #MAX_FDS
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inv: rts
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.endproc
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