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CPM OPERATING SYSTEMS/CPM 8000 (CPM8K)/P-CP M-Z8K SOURCES/newos/membcp.c

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+
+/*=======================================================================*/
+/*+---------------------------------------------------------------------+*/
+/*|									|*/
+/*|     P-CP/M(tm)  Block Move  for the KONTRON BOARD (Z8002)		|*/
+/*|									|*/
+/*|     Copyright 1982, Zilog Incorporated.				|*/
+/*|									|*/
+/*+---------------------------------------------------------------------+*/
+/*=======================================================================*/
+
+char copyright[] = "Copyright 1982, Zilog Incorporated";
+
+/* HISTORY
+**
+**	830111	F. Zlotnick (Zilog)
+**	830121	D. Heintz (Me) Fixed bug in s/d window computation
+*/
+ 
+mem_bcp( sseg, source, dseg, dest, length)/* sseg and dseg are pseudo-segment */
+unsigned short sseg, source, dseg, dest;/*  numbers from mem_copy.	    */
+unsigned short length;			/*  source and dest are offsets in  */
+					/*  the pseudo-segments.  length is */
+					/*  the number of bytes to be copied*/
+{
+	register unsigned length1, length2;
+	register unsigned middle;
+	short swindow, dwindow;
+	unsigned short blength;
+	static char locbuf[256];	/* intermediate buffer */
+
+/* deal recursively with the possibility of crossing the half-segment line */
+
+	middle = 0x8000;
+
+	if(source < middle && source + length > middle) {
+		length1 = middle - source;	/* first half */
+		length2 = length - length1;	/* second half */
+		mem_bcp(sseg,source,dseg,dest,length1);	/* recurse */
+		mem_bcp(sseg,middle,dseg,dest+length1,length2);/* recurse */
+		return;
+	}
+
+	if(dest < middle && dest + length > middle) {
+		length1 = middle - dest;	/* first half */
+		length2 = length - length1;	/* second half */
+		mem_bcp(sseg,source,dseg,dest,length1);	/* recurse */
+		mem_bcp(sseg,source+length1,dseg,middle,length2);/* recurse */
+		return;
+	}
+
+/*
+ * This part is non-recursive.  If you get this far, you're guaranteed
+ * not to cross a mid-segment boundary on either the source or dest
+ * blocks.
+ */
+
+	swindow = ((sseg >> 8) << 1) | ( (source >= middle) ? 1 : 0);
+	dwindow = ((dseg >> 8) << 1) | ( (dest >= middle) ? 1 : 0);
+	if ( swindow == dwindow ) {	/* Both in same window */
+		map_wdw(swindow);
+		if(swindow != 0) {		/* If really mapped, then */
+			source |= 0x8000;	/*  must be in upper half */
+			dest |= 0x8000;		/*  of system address space */
+		}
+		blkmov(source,dest,length);
+	}
+	else if(swindow != 0 && dwindow != 0) {
+		source |=  0x8000;
+		dest |=  0x8000;
+		while(length > 0) {
+			blength = (length > 256)? 256: length ;
+			map_wdw(swindow);
+			blkmov(source,locbuf,blength);	/* Assumes pointers*/
+			map_wdw(dwindow);		/*  are short!     */
+			blkmov(locbuf,dest,blength);	/* Ditto	   */
+			source += blength;
+			dest += blength;
+			length -= blength;
+		}
+	}
+	else {
+		if ( swindow == 0 ) {	/* System lower half: no window */
+			map_wdw(dwindow);	/* Put dest block in upper */
+			dest |= 0x8000;		/*  half of system space */
+		}
+		else if ( dwindow == 0 ) {
+			map_wdw(swindow);	/* Put source block in upper */
+			source |= 0x8000;	/*  half of system space */
+		}
+		while ( length > 0 ) {
+			blength = (length > 256)? 256: length ;
+			blkmov(source,dest,blength);
+			source += blength;
+			dest += blength;
+			length -= blength;
+		}
+	}
+}