Bftsth - T - Motorola DSP56800 Manual

BFTSTH
Operation:
Test <bit field> of destination for ones
Test <bit field> of destination for ones
Description: Test all selected bits of the destination operand. If all selected bits are set, C is set; otherwise, C is
cleared. The bits to be tested are selected by a 16-bit immediate value in which every bit set is to be
tested. This instruction performs two destination accesses.
Usage:
This instruction is very useful for testing I/O and flag bits.
Example:
BFTSTH
Before Execution
X:$FFE2
SR
Explanation of Example:
Prior to execution, the 16-bit X memory location X:$FFE2 contains the value $0FF0. Execution of the
instruction tests the state of bits 4, 8, and 9 in X:$FFE2 and sets C (because all the CCR bits were set).
Condition Codes Affected:
15 14
LF *
Note:
If all bits in the mask are set to zero, the destination is unchanged, and the C bit is set.
A-56
Test Bit Field High
#$0310,X:<<$FFE2
0FF0
0000
MR
13 12 11 10 9
* * * * I1
L — Set if data limiting occurred during 36-bit source move
C — Set if all bits specified by the mask are set
Clear if not all bits specified by the mask are set
DSP56800 Family Manual
Assembler Syntax:
BFTSTH
BFTSTH
; test high bits 4, 8, and 9 in
; an on-chip peripheral register
After Execution
X:$FFE2
SR
CCR
8 7 6 5 4
L
I0 SZ E U
BFTSTH
#iiii,X:<ea>
#iiii,D
0FF0
0001
3 2 1 0
C
N Z V