MPLAB C Compiler for PIC24 MCUs and dsPIC DSCs ... - Microchip

16-Bit C Compiler User’s Guide
__builtin_movsac
Argument: xptr Integer pointer to pointer to x prefetch.
xval Integer pointer to value of x prefetch.
xincr Integer increment value of x prefetch.
yptr Integer pointer to pointer to y prefetch.
yval Integer pointer to value of y prefetch.
yincr Integer increment value of y prefetch.
AWB Integer pointer to accumulator selection.
Return Value: Returns prefetch data.
Assembler Operator
/ Machine
Instruction:
movsac
Error Messages An error message will be displayed if:
• the result is not an accumulator register
• xval is a null value but xptr is not null
• yval is a null value but yptr is not null
__builtin_mpy
Description: Computes a x b ; also prefetchs data ready for a future MAC operation.
xptr may be null to signify no X prefetch to be performed, in which
case the values of xincr and xval are ignored, but required.
yptr may be null to signify no Y prefetch to be performed, in which
case the values of yincr and yval are ignored, but required.
xval and yval nominate the address of a C variable where the
prefetched value will be stored.
xincr and yincr may be the literal values: -6, -4, -2, 0, 2, 4, 6 or an
integer value.
For example:
register int result asm("A");
int *xmemory;
int *ymemory;
int xVal, yVal;
result = __builtin_mpy(xVal, yVal,
&xmemory, &xVal, 2,
&ymemory, &yVal, 2);
Prototype:
might generate:
mac w4*w5, A, [w8]+=2, w4, [w10]+=2, w5
int __builtin_mpy(int a, int b,
int **xptr, int *xval, int xincr,
int **yptr, int *yval, int yincr);
Argument: a Integer multiplicand.
b Integer multiplier.
xptr Integer pointer to pointer to x prefetch.
xval Integer pointer to value of x prefetch.
xincr Integer increment value of x prefetch.
yptr Integer pointer to pointer to y prefetch.
yval Integer pointer to value of y prefetch.
yincr Integer increment value of y prefetch.
AWB Integer pointer to accumulator selection.
Return Value: Returns the cleared value result to an accumulator.
Assembler Operator
/ Machine
Instruction:
mpy
DS51284G-page 152 © 2008 Microchip Technology Inc.