AVR Instruction Set Nomenclature: Status Register (SREG ...
AVR Instruction Set Nomenclature: Status Register (SREG ...
AVR Instruction Set Nomenclature: Status Register (SREG ...
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CPSE - Compare Skip if Equal<br />
<strong>Instruction</strong> <strong>Set</strong><br />
Description:<br />
This instruction performs a compare between two registers Rd and Rr, and skips the next instruction if Rd = Rr.<br />
Operation:<br />
(i) If Rd = Rr then PC ← PC + 2 (or 3) else PC ← PC + 1<br />
Syntax: Operands: Program Counter:<br />
(i) CPSE Rd,Rr 0 ≤ d ≤ 31, 0 ≤ r ≤ 31 PC ← PC + 1, Condition false - no skip<br />
PC ← PC + 2, Skip a one word instruction<br />
PC ← PC + 3, Skip a two word instruction<br />
16-bit Opcode:<br />
<strong>Status</strong> <strong>Register</strong> (<strong>SREG</strong>) and Boolean Formula:<br />
Example:<br />
0001 00rd dddd rrrr<br />
I T H S V N Z C<br />
- - - - - - - -<br />
inc r4 ; Increase r4<br />
cpse r4,r0 ; Compare r4 to r0<br />
neg r4 ; Only executed if r4r0<br />
nop ; Continue (do nothing)<br />
Words: 1 (2 bytes)<br />
Cycles: 1 if condition is false (no skip)<br />
2 if condition is true (skip is executed) and the instruction skipped is 1 word<br />
3 if condition is true (skip is executed) and the instruction skipped is 2 words<br />
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