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b2e0ed603e
changed/added some comments all cbm_* IO functions are using _oserror now git-svn-id: svn://svn.cc65.org/cc65/trunk@682 b7a2c559-68d2-44c3-8de9-860c34a00d81
36 lines
955 B
C
36 lines
955 B
C
/*
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* Marc 'BlackJack' Rintsch, 19.03.2001
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*
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* int cbm_read(unsigned char lfn, void* buffer, unsigned int size);
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*/
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#include <cbm.h>
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extern unsigned char _oserror;
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int cbm_read(unsigned char lfn, void* buffer, unsigned int size)
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{
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static unsigned int bytesread;
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static unsigned char tmp;
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/* if we can't change to the inputchannel #lfn then return an error */
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if (_oserror = cbm_k_chkin(lfn)) return -1;
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bytesread = 0;
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while (bytesread<size && !cbm_k_readst()) {
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tmp = cbm_k_basin();
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/* the kernal routine BASIN sets ST to EOF if the end of file
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* is reached the first time, then we have store tmp.
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* every subsequent call returns EOF and READ ERROR in ST, then
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* we have to exit the loop here immidiatly. */
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if (cbm_k_readst() & 0xBF) break;
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((unsigned char*)buffer)[bytesread++] = tmp;
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}
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cbm_k_clrch();
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return bytesread;
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}
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