Analog Devices ADSP-BF53x Blackfin Reference page 728

Instruction Overview
/* MAC1 multiplies a signed fraction by an unsigned fraction.
MAC0 multiplies two signed fractions. */
r5.h=r3.h*r2.h (m), r5.l=r3.l*r2.l (fu) ;
/* MAC1 multiplies signed fraction by unsigned fraction. MAC0
multiplies two unsigned fractions. */
r0.h=r3.h*r2.h, r0.l=r3.l*r2.l (is) ;
/* both MACs perform signed integer multiplication. */
r3.h=r0.h*r1.h, r3.l=r0.l*r1.l (s2rnd) ;
/* MAC1 and MAC0 multiply signed fractions. Both scale the result
on the way to the destination register. */
r0.l=r7.l*r6.l, r0.h=r7.h*r6.h (iss2) ;
/* both MACs process signed integer operands and scale and round
the result on the way to the destination half-registers. */
r7=r2.l*r5.l, r6=r2.h*r5.h ;
/* both operations produce 32-bit results and save in a Dreg
pair. */
r0=r4.l*r7.l, r1=r4.h*r7.h (s2rnd) ;
/* same as above, but with signed fraction scaling mode. Order of
the MAC instructions makes no difference. */
19-40 ADSP-BF53x/BF56x Blackfin Processor Programming Reference