dsp56800 Freescale Semiconductor, Inc, dsp56800 Datasheet - Page 391

• Manufacturer Part Number: dsp56800
• Description: 16-bit Digital Signal Controllers
• Manufacturer: Freescale Semiconductor, Inc

TST
Operation:
S - 0
S - 0
Description: Compare the specified source accumulator (S) with zero, and set the condition codes accordingly. No
Example:
Explanation of Example:
Condition Codes Affected:
Freescale Semiconductor
Before Execution
A2
SR
(single parallel move)
8
result is stored, although the condition codes are updated. The result is not affected by the state of the
saturation bit (SA).
TST
Prior to execution, the 36-bit A accumulator contains the value $8:0203:0000, and the 16-bit SR con-
tains the value $0300. Execution of the TST A instruction compares the value in the A register with
zero and updates the CCR accordingly. The contents of the A accumulator are not affected.
See Section 3.6.2, “36-Bit Destinations — CC Bit Set,” on page 3-34 and Section 3.6.4, “20-Bit Des-
tinations — CC Bit Set,” on page 3-34 for the case when the CC bit is set.
15
LF
0203
0300
14
A1
*
SZ — Set according to the standard definition of the SZ bit (parallel move)
L
E
U
N
Z
V
C
13
*
— Set if data limiting has occurred during parallel move
— Set if the extension portion of accumulator result is in use
— Set according to the standard definition of the U bit
— Set if bit 35 of accumulator result is set
— Set if result equals zero
— Always cleared
— Always cleared
A
12
*
MR
11
*
0000
A0
Test Accumulator
10
X:(R0)+N,B
*
Instruction Set Details
I1
9
Assembler Syntax:
TST
TST
I0
8
SZ
7
After Execution
L
6
A2
SR
8
E
5
S
S
; set condition codes for the
;
U
4
CCR
0203
0338
A1
value in A, update B & R0
N
3
Z
2
V
(single parallel move)
1
0000
C
0
A0
TST
A-161