Texas Instruments TMS320C28x Reference Manual page 386

MPY P,loc16,#16bit
SYNTAX OPTIONS
MPY P,loc16,#16bit
Operands P
loc16
#16bit
Description
Flags and
Modes
Repeat
Example
; ; Calculate using 16-bit multiply:
; Y = (X0*C0) >> 2) + (X1*C1 >> 2) + (X2*C2 >> 2),
; C0, C1 and C2 are constants
SPM
MOVB
MPY
MPYA
MPYA
ADDL
MOVL
1000 1100 LLLL LLLL
CCCC CCCC CCCC CCCC
Product register
Addressing mode (see Chapter 5)
16-bit immediate constant value
Multiply the signed 16-bit contents of the location pointed to by the "loc16"
addressing mode by the 16-bit immediate value and store the 32-bit result in
the P register:
P = signed [loc16] * signed 16bit;
None
This instruction is not repeatable. If this instruction follows the RPT
instruction, it resets the repeat counter (RPTC) and executes only once.
−2 ; Set product shift to >> 2
ACC,#0 ; Zero ACC
P,@X2,#C2 ; P = X2*C2
P,@X1,#C1 ; ACC = X2*C2>>2, P = X1*C1
P,@X0,#C0 ; ACC = X1*C1>>2 + X2*C2>>2, P = X0*C0
ACC,P << PM ; ACC = X0*C0>>2 + X1*C1>>2 + X2*C2>>2
@Y,ACC ; Store result into Y
OPCODE OBJMODE
MPY P,loc16,#16bit
16 X 16-Bit Multiply
RPT CYC
1 − 1
6-229