dsp56800e Freescale Semiconductor, Inc, dsp56800e Datasheet - Page 381

• Manufacturer Part Number: dsp56800e
• Description: 16-bit Digital Signal Controller Core
• Manufacturer: Freescale Semiconductor, Inc

ASL.W
Operation:
(see following figure)
:
Description: Arithmetically shift the destination operand (D) 1 bit to the left, and store the result in the destination
Example:
Explanation of Example:
Condition Codes Affected:
Freescale Semiconductor
Before Execution
register. The MSB, bit 15 of the destination prior to the execution of the instruction, is shifted into C,
and a zero is shifted into the LSB of the destination. This instruction is used only when the destination
is X0, Y0, or Y1 register. For the purpose of calculating condition code, the 16-bit register is first sign
extended and concatenated to 16 zero bits to form a 36-bit operand. For arithmetic shifts left on the Y
register or accumulator, refer to ASL.
ASL.W
Prior to execution, the 16-bit Y0 register contains the value $C000. Execution of the ASL.W instruc-
tion shifts the 16-bit value in Y0 by 1 bit to the left and stores the result back in Y0. C is set by the
operation because bit 15 of Y0 was set prior to the execution of the instruction. The N bit is set because
the MSB of the result is set.
L
E
U
N
Z
V
C
2000
Y1
LF
15
— Set if overflow has occurred in result
— Set if the extension portion of the result is in use
— Set according to the standard definition of the U bit
— Set if bit 15 of result is set
— Set if the result equals zero
— Set if bit 15 of result is changed due to left shift
— Set if bit 15 of was set prior to the execution of the instruction
P4
14
SR
Y0
13
P3
P2
12
C000
0300
MR
C
Y0
P1
11
; shift Y0 left by 1
Arithmetic Shift Left
P0
10
15
Instruction Set Details
I1
9
Assembler Syntax:
ASL.W
I0
8
SZ
7
0
After Execution
6
L
5
E
2000
0
Y1
D
U
4
CCR
SR
N
3
(no parallel move)
2
Z
8000
0309
Y0
V
1
C
0
ASL.W
A-37