To set or clear a bit within a byte variable based upon a bit in the same or other byte variable try:
(byte2 &= ~BITMASK2), (byte1 & BITMASK1) ? (byte2 |= BITMASK2) : 0;
Which could be encapsulated into a macro:
#define setmask(b1, m1, b2, m2) (((b2) &= ~(m2)), ((b1) & (m1)) ? ((b2) |= (m2)) : 0)
which you would use thusly:
setmask(byte1, BITMASK1, byte2, BITMASK2);
The result for the PIC is:
bcf _byte2,3 btfsc _byte1,2 bsf _byte2,3
Which is very effecient. If you don't want to clear the bit first (e.g. if it was a port pin) then it would be:
(!(byte1 & BITMASK1) ? (byte2 &= ~BITMASK2) : 0), (byte1 & BITMASK1) ? (byte2 |= BITMASK2) : 0;
PIC - Bit operations@
|file: /Techref/language/ccpp/bittwid.htm, 1KB, , updated: 2008/3/19 02:23, local time: 2018/9/21 10:02,
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<A HREF="http://www.piclist.com/techref/language/ccpp/bittwid.htm"> Efficient bit twiddeling in C</A>
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