Texas Instruments TMS320C28x, Reference Manual

Page: 392 / 695

MPYB ACC,T,#8bit
6-235
MPYB ACC,T,#8bit
Multiply by 8-bit Constant
SYNTAX OPTIONS OPCODE OBJMODE RPT CYC
MPYB ACC,T,#8bit
0011 0101 CCCC CCCC
X − 1
Operands ACC Accumulator register
T Multiplicand register
#8bit 8-bit immediate constant value
Description Multiply the signed 16-bit content of the T register by the unsigned 8-bit
constant value zero extended and store the result in the ACC register:
ACC = signed T * 0:8bit
Flags and
Modes
Z After the operation, the Z flag is set if the ACC is zero, else Z is cleared.
N After the operation, the N flag is set if bit 31 of the ACC is 1, else N is
cleared.
Repeat This instruction is not repeatable. If this instruction follows the RPT
instruction, it resets the repeat counter (RPTC) and executes only once.
Example
; Calculate signed using 16-bit multiply:
; Y32 = Y32 + (X16 * 5)
MOV T,@X16 ; T = X16
MPYB ACC,T,#5 ; ACC = T * 5
ADDL @Y32,ACC ; Y32 = Y32 + ACC