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https://github.com/SEPPDROID/Digital-Research-Source-Code.git
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46 lines
1.6 KiB
C
46 lines
1.6 KiB
C
/*****************************************************************************
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*
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* I G E T C / F R E E C R O U T I N E S
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* -------------------------------------------
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*
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* Routines "igetc" and "freec" are used to allocate / deallocate a
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* channel number so that the user may do I/O directly without the OTS
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* getting in the way.
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*
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* Calling Sequence:
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*
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* i = getc();
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* freec(i);
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*
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*****************************************************************************/
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#include "stdio.h" /* Include std definitions */
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#include "cpm.h" /* Also CP/M ones */
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WORD chmask = 0; /* Allocate storage */
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WORD igetc() /****************************/
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{ /* */
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REG i,j; /* Define 2 temporaries */
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/* */
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j = 1; /* Start with channel 0 */
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for(i=0;i<MAXFILE;i++) /* Look at all 16 bits */
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{ /* */
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if((j & chmask) == 0) /* If 0, then channel free */
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{ /* */
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chmask |= j; /* set allocated bit */
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return(i); /* and return the channel # */
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} /* */
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j = j << 1; /* Up to next bit */
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} /* End FOR loop */
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return(FAILURE); /* All channels in use! */
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} /****************************/
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WORD freec(ch) /****************************/
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{ /* */
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REG i,j; /* Define 2 temporaries */
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/* */
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j = 1; /* Start with channel 0 */
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for (i=0; i<ch; i++) /* Compute */
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j = j << 1; /* bit mask */
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chmask &= (~j); /* clear allocation bit */
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return(SUCCESS); /* Return OK */
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} /****************************/
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