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CHAPTER 7 DETAILED EXECUTION INSTRUCTIONS
7.33 BTSTH (Test Higher 4 Bits of Byte Data in Memory)
Takes the logical AND of the 4-bit immediate data and the higher 4 bits of byte data at
memory address "Ri", places the results in the condition code register (CCR).
■ BTSTH (Test Higher 4 Bits of Byte Data in Memory)
Assembler format: BTSTH #u4, @Ri
Operation: {u4 < < 4} and (Ri) [Test uses higher 4 bits only]
Flag change:
N: Set when the MSB (bit 7) of the operation result is "1", cleared when the MSB is "0".
Z: Set when the operation result is "0", cleared otherwise.
V and C: Unchanged
Execution cycles: 2 + a cycles
Instruction format:
Example: BTSTH #1, @R3
NZVC
CC– –
MSB LSB
10001001 u4 Ri
12345678
12345679
1234 5678
NZVC
CCR
R3R3
CCR
0000
01
NZVC
0100
1234 5678
12345678
12345679
01
Instruction bit pattern : 1000 1001 0001 0011
Before execution After execution
Memory Memory