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CHAPTER 7 DETAILED EXECUTION INSTRUCTIONS
7.32 BTSTL (Test Lower 4 Bits of Byte Data in Memory)
Takes the logical AND of the 4-bit immediate data and the lower 4 bits of byte data at
memory address "Ri", places 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: Cleared
Z: Set when the operation result is "0", cleared otherwise.
V and C: Unchanged
Execution cycles: 2+a cycles
Instruction format:
Example: BTSTL #1, @R3
NZVC
0C––
MSB LSB
10001000 u4 Ri
12345678
12345679
1234 5678
NZVC
CCR
R3R3
CCR
0000
10
NZVC
0100
1234 5678
12345678
12345679
10
Instruction bit pattern : 1000 1000 0001 0011
Before execution After execution
Memory Memory