Texas Instruments C28 Series

Multiplier
Basic Multiplier
Multiplier Instructions
Instruction Execution Purpose
MOV T,loc16 T = loc16 Get first operand
MPY ACC,T,loc16 ACC = T*loc16 For single or first product
MPY P,T,loc16 P = T*loc16 For n
th
product
MPYB ACC,T,#8bu ACC = T*8bu Using 8-bit unsigned const
MPYB P,T,#8bu P = T*8bu Using 8-bit unsigned const
MOV ACC,P ACC = P Move 1
st
product<<PM to ACC
ADD ACC,P ACC += P Add n
th
product<<PM to ACC
SUB ACC,P ACC -= P Sub n
th
product<<PM fr. ACC
Instruction
MPYA P, T, #16b ACC += P<<PM then P = T*#16b
MPYA P, T, loc16 ACC += P<<PM then P = T*loc16
MPYS P, T, loc16 ACC - = P<<PM then P = T*loc16
Execution
MOVP T, loc16 ACC = P<<PM T = loc16
MOVA T, loc16 ACC += P<<PM T = loc16
MOVS T, loc16 ACC - = P<<PM T = loc16
Sum-of-Products
ZAPA ;ACC = P = OVC = 0
MOV T,@X1 ;T = X1
MPY P,T,@A ;P = A*X1
MOVA T,@X2 ;T = X2 ;ACC = A*X1
MPY P,T,@B ;P = B*X2
MOVA T,@X3 ;T = X3 ;ACC = A*X1 + B*X2
MPY P,T,@C ;P = C*X3
MOVA T,@X4 ;T = X4;ACC = A*X1 + B*X2 + C*X3
MPY P,T,@D ;P = D*X4
ADDL ACC,P<<PM ;ACC = Y
MOVL @y,ACC
Y = A*X1 + B*X2 + C*X3 + D*X4
Y = A*X1 + B*X2 + C*X3 + D*X4
C - 10 C28x - Appendix C - Assembly Programming