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 bf561 汇编指令集（二）

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位操作指令

Bit Operations
bitclr (r2, 3) ;   /* clear bit 3 (the fourth bit from LSB) in R2 */
bitset (r2, 7) ;   /* set bit 7 (the eighth bit from LSB) in R2 */
bittgl (r2, 24) ;   /* toggle bit 24 (the 25th bit from LSB in R2 */
cc = bittst (r7, 15) ;   /* test bit 15 TRUE in R7 */
cc = ! bittst (r3, 0) ;   /* test bit 0 FALSE in R3 */
r7 = deposit (r4, r3) ;                   /* Special Applications：Video image overlay algorithms */

r7 = extract (r4, r3.l) (x) ;            /*Special Applications Video image pattern recognition and separation algorithms */

bitmux (r2, r3, a0) (asr) ;   /* right shift*/
bitmux (r3, r2, a0) (asl) ;   /* left shift*/
r3.l = ones r7 ; /*loads the number of 1’s*/   /*Special Applications
Software parity testing */

Shift/Rotate Operations
Add with Shift
p3 = (p3+p2)<<2 ;
r3 = (r3+r2)<<1 ;
Shift with Add
p3 = p0+(p3<<1) ;
Arithmetic Shift
r0 >>>= 19 ;
r3.l = r0.h << 12 (S) ;
r3.l = r0.h >>> 7(s) ;
r4 = ashift r2 by r7.l ;  
A1 = ashift A1 by r7.l ;
Logical Shift
p3 = p2 >> 1 ;
r3.h = r0.h << 14 ;
a0 = lshift a0 by r7.l ;
ROT (Rotate)
r4 = rot r1 by 8 ;
a1 = rot a1 by -31 ;  
r4 = rot r1 by r2.l ;

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