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44 lines
832 B
ArmAsm
44 lines
832 B
ArmAsm
;
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; Ullrich von Bassewitz, 17.06.1998
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;
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; int _fdesc (void);
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; /* Find a free descriptor slot */
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.export __fdesc
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.import return0
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.include "stdio.inc"
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.include "_file.inc"
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.proc __fdesc
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ldy #0
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lda #_FOPEN
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Loop: and __filetab + _FILE_f_flags,y ; load flags
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beq Found ; jump if closed
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.repeat ::_FILE_size
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iny
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.endrepeat
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cpy #(FOPEN_MAX * _FILE_size) ; Done?
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bne Loop
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; File table is full
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jmp return0
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; Free slot found, get address
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Found: tya ; Offset
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clc
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adc #<__filetab
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ldx #>__filetab ; High byte
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bcc @L1 ; Jump if no overflow
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inx ; Bump high byte
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@L1: rts
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.endproc
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