Texas Instruments TMS320C2XX - Manual (Page 280)

Normalize Contents of Accumulator NORM
7-127 Assembly Language Instructions
Notes:
For the NORM instruction, the auxiliary register operations are executed dur-
ing the fourth phase of the pipeline, the execution phase. For other instruc-
tions, the auxiliary register operations take place in the second phase of the
pipeline, in the decode phase. Therefore:
1) The auxiliary register values should not be modified by the two
instruction words following NORM. If the auxiliary register used in the
NORM instruction is to be affected by either of the next two instruction
words, the auxiliary register value will be modified by the other instruc-
tions
before it is modified by the NORM instruction.
2) The value in the auxiliary register pointer (ARP) should not be mo-
dified by the two instruction words following NORM. If either of the
next two instruction words specify a change in the ARP value, the ARP
value will be changed
before NORM is executed; the ARP will not be
pointing at the correct auxiliary register when NORM is executed.
Words 1
Cycles for a Single NORM Instruction
ROM DARAM SARAM External
1 1 1 1+p
Cycles for a Repeat (RPT) Execution of a NORM Instruction
ROM DARAM SARAM External
n n n n+p
Example 1 NORM *+
Before Instruction After Instruction
ARP 2 ARP 2
AR2 00h AR2 01h
ACC X 0FFFFF001h ACC X 0FFFE002h
C C
X 0
TC TC
Example 2 31-Bit Normalization:
MAR *,AR1 ;Use AR1 to store the exponent.
LAR AR1,#0h ;Clear out exponent counter.
LOOP NORM *+ ;One bit is normalized.
BCND LOOP,NTC ;If TC = 0, magnitude not found yet.
Cycles