MPLAB C Compiler for PIC24 MCUs and dsPIC DSCs ... - Microchip
MPLAB C Compiler for PIC24 MCUs and dsPIC DSCs ... - Microchip
MPLAB C Compiler for PIC24 MCUs and dsPIC DSCs ... - Microchip
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16-Bit C <strong>Compiler</strong> User’s Guide<br />
__builtin_ed<br />
Error Messages An error message will be displayed if:<br />
• the result is not an accumulator register<br />
• xptr is null<br />
• yptr is null<br />
• distance is null<br />
__builtin_edac<br />
Description: Squares sqr <strong>and</strong> sums with the nominated accumulator register,<br />
returning it as the result. Also prefetchs data <strong>for</strong> future square operation<br />
by computing **xptr - **yptr <strong>and</strong> storing the result in *distance.<br />
xincr <strong>and</strong> yincr may be the literal values: -6, -4, -2, 0, 2, 4, 6 or an<br />
integer value.<br />
For example:<br />
register int result asm("A");<br />
int *xmemory, *ymemory;<br />
int distance;<br />
result = __builtin_ed(distance,<br />
&xmemory, 2,<br />
&ymemory, 2,<br />
&distance);<br />
Prototype:<br />
might generate:<br />
ed w4*w4, A, [w8]+=2, [W10]+=2, w4<br />
int __builtin_edac(int sqr, int **xptr, int xincr,<br />
int **yptr, int yincr, int *distance);<br />
Argument: sqr Integer squared value.<br />
xptr Integer pointer to pointer to x prefetch.<br />
xincr Integer increment value of x prefetch.<br />
yptr Integer pointer to pointer to y prefetch.<br />
yincr Integer increment value of y prefetch.<br />
distance Integer pointer to distance.<br />
Return Value: Returns the squared result to specified accumulator.<br />
Assembler Operator<br />
/ Machine<br />
Instruction:<br />
edac<br />
Error Messages An error message will be displayed if:<br />
• the result is not an accumulator register<br />
• xptr is null<br />
• yptr is null<br />
• distance is null<br />
__builtin_fbcl<br />
Description: Finds the first bit change from left in value. This is useful <strong>for</strong> dynamic<br />
scaling of fixed-point data. For example:<br />
int result, value;<br />
result = __builtin_fbcl(value);<br />
might generate:<br />
fbcl w4, w5<br />
Prototype: int __builtin_fbcl(int value);<br />
DS51284G-page 148 © 2008 <strong>Microchip</strong> Technology Inc.