Texas Instruments TMS320C28x Reference Manual page 300

LSR64 ACC:P,T
SYNTAX OPTIONS
LSR64 ACC:P,T
Operands ACC:P Accumulator register (ACC) and product register (P)
T
Description
Flags and
N
Modes
Z
C
Repeat
Example
; Arithmetic shift right the 64-bit Var64 by contents of Var16:
MOVL
MOVL
MOV
LSR64 ACC:P,T
MOVL
MOVL
Upper 16 bits of the multiplicand register (XT)
Logical shift right the 64-bit combined value of the ACC:P registers by the
amount specified by the six least significant bits of the T register,
T(5:0) = 0...63. Higher order bits are ignored. As the value is shifted, the
most significant bits are zero filled. If T specifies a shift of 0, then C is cleared;
otherwise, C is filled with the last bit to be shifted out of the ACC:P registers:
0
After the shift, if bit 31 of the ACC register is 1 then ACC:P is negative and the
N bit is set; otherwise N is cleared.
After the shift, the Z flag is set if the combined 64-bit value of the ACC:P is
zero; otherwise, Z is cleared.
If (T(5:0) = 0) clear C; otherwise, the last bit shifted out of the combined 64-bit
value is loaded into the C bit.
This instruction is not repeatable. If this instruction follows the RPT
instruction, it resets the repeat counter (RPTC) and executes only once.
ACC,@Var64+2
P,@Var64+0
T,@Var16
@Var64+2,ACC
@Var64+0,P
64-Bit Logical Shift Right by T(5:0)
OPCODE
0101 0110 0101 1011
ACC:P
Right shift
(Contents of T(5:0)
ACC:P
; Load ACC with high 32 bits of Var64
; Load P with low 32 bits of Var64
; Load T with shift value from Var16
; Logical shift right ACC:P by T(5:0)
; Store high 32-bit result into Var64
; Store low 32-bit result into Var64
LSR64 ACC:P,T
OBJMODE RPT CYC
1 − 1
Last bit out or cleared
C
Discard
other bits
6-143