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AVR Instruction Set Nomenclature: Status Register (SREG ...

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BRID - Branch if Global Interrupt is Disabled<br />

<strong>Instruction</strong> <strong>Set</strong><br />

Description:<br />

Conditional relative branch. Tests the Global Interrupt flag (I) and branches relatively to PC if I is cleared. This instruction<br />

branches relatively to PC in either direction (PC - 63 ≤ destination ≤ PC + 64). The parameter k is the offset from PC and is<br />

represented in two’s complement form. (Equivalent to instruction BRBC 7,k).<br />

Operation:<br />

(i) If I = 0 then PC ← PC + k + 1, else PC ← PC + 1<br />

Syntax: Operands: Program Counter:<br />

(i) BRID k -64 ≤ k ≤ +63 PC ← PC + k + 1<br />

PC ← PC + 1, if condition is false<br />

16-bit Opcode:<br />

<strong>Status</strong> <strong>Register</strong> (<strong>SREG</strong>) and Boolean Formula:<br />

Example:<br />

1111 01kk kkkk k111<br />

I T H S V N Z C<br />

- - - - - - - -<br />

brid intdis<br />

...<br />

; Branch if interrupt disabled<br />

intdis: nop ; Branch destination (do nothing)<br />

Words: 1 (2 bytes)<br />

Cycles: 1 if condition is false<br />

2 if condition is true<br />

25

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