CHAPTER 7 DETAILED EXECUTION INSTRUCTIONS
7.32
BTSTL (Test Lower 4 Bits of Byte Data in Memory)
Take the logical AND of the 4-bit immediate data and the lower 4 bits of byte data at
memory address "Ri", place the results in the condition code register (CCR).
■ BTSTL (Test Lower 4 Bits of Byte Data in Memory)
Assembler format:
BTSTL #u4, @Ri
Operation:
u4 and (Ri) [Test uses lower 4 bits only]
Flag change:
N:
Z:
V and C: Unchanged
Execution cycles:
2+a cycles
Instruction format:
Example:
BTSTL #1, @R3
118
N
Z
V
C
0
C
–
–
Cleared
Set when the operation result is "0", cleared otherwise.
MSB
1
0
0
0
Instruction bit pattern :
1000 1000 0001 0011
R3
1 2 3 4 5 6 7 8
Memory
12345678
1 0
12345679
N Z V C
CCR
0 0 0 0
Before execution
1
0
0
0
u4
LSB
Ri
R3
1 2 3 4 5 6 7 8
Memory
12345678
1 0
12345679
N Z V C
CCR
0 1 0 0
After execution