Texas Instruments TMS320C2XX - Manual (Page 249)

LTD Load TREG, Accumulate Previous Product, and Move Data
7-96
Words 1
Cycles for a Single LTD Instruction
Program
Operand ROM DARAM SARAM External ‡
DARAM 1 1 1 1+p
SARAM 1 1 1, 3 † 1+p
External 2+2d 2+2d 2+2d 5+2d+p
† If the operand and the code are in the same SARAM block
‡ If the LTD instruction is used with external memory, the data move will not occur. (The previous
product will be accumulated, and the TREG will be loaded.)
Cycles for a Repeat (RPT) Execution of an LTD Instruction
Program
Operand ROM DARAM SARAM External ‡
DARAM n n n n+p
SARAM 2n–2 2n–2 2n–2, 2n+1 † 2n–2+p
External 4n–2+2nd 4n–2+2nd 4n–2+2nd 4n+1+2nd+p
† If the operand and the code are in the same SARAM block
‡ If the LTD instruction is used with external memory, the data move will not occur. (The previous
product will be accumulated, and the TREG will be loaded.)
Example 1 LTD 126 ;(DP = 7: addresses 0380h–03FFh,
;PM = 0: no shift of product).
Before Instruction After Instruction
Data Memory Data Memory
3FEh 62h 3FEh 62h
Data Memory Data Memory
3FFh 0h 3FFh 62h
TREG 3h TREG 62h
PREG 0Fh PREG 0Fh
ACC X 5h ACC 0 14h
C C
Cycles