Description:
This instruction tests a single bit in an I/O register and skips the next instruction if the bit is set. This instruction operates on the lower 32 I/O registers - addresses 0-31.
Operation:
(i)If I/O(A,b) = 1 then PC ← PC + 2 (or 3) else PC ← PC + 1
Syntax: Operands: Program Counter:
(i)SBIS A,b 0 ≤ A ≤ 31, 0 ≤ b ≤ 7 PC ← PC + 1, Condition false - no skip
PC ← PC + 2, Skip a one word instruction
PC ← PC + 3, Skip a two word instruction
16-bit Opcode:
|
1001 |
1011 |
AAAA |
Abbb |
Status Register (SREG) and Boolean Formula:
|
I |
T |
H |
S |
V |
N |
Z |
C |
|---|---|---|---|---|---|---|---|
|
- |
- |
- |
- |
- |
- |
- |
- |
Example:
waitset: sbis $10,0 ; Skip next inst. if bit 0 in Port D set rjmp waitset ; Bit not set nop ; Continue (do nothing)
Words:1 (2 bytes)
|
Cycles |
Cycles xmega |
Cycles AVR8L | |
|---|---|---|---|
|
Condition is false |
1 |
2 |
1 |
|
Condition is true and instruction skipped is 1 word |
2 |
3 |
2 |
|
Condition is true and instruction skipped is 2 words |
3 |
4 |
N/A |