Arm VERSION 1.2 Manuel d'utilisateur télécharger pdf (Page 223)

100

101

Thumb Instruction Reference

Condition flags

MOV Rd,#expr

and

MVN

instructions update the N and Z flags. They have no effect on the

C or V flags.

NEG

instructions update the N, Z, C, and V flags.

MOV Rd, Rm

behaves as follows:

• if either

is a high register (

r15

), the flags are unaffected

• if both

and

are low registers (

), the N and Z flags are updated, and C

and V flags are cleared.

Note

You can use

LSL

, with a shift of zero, to move between low registers without

clearing the C and V flags (see ASR, LSL, LSR, and ROR on page 5-24).

Architectures

These instructions are available in all T variants of the ARM architecture.

Examples

MOV r3,#0

MOV r0,r12 ; does not update flags

MVN r7,r1

NEG r2,r2

Incorrect examples

MOV r2,#256 ; immediate value out of range

MOV r8,#3 ; cannot move immediate to high register

MVN r8,r2 ; high registers not allowed with MVN or NEG

NEG r0,#3 ; immediate value not allowed with MVN or NEG

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Arm VERSION 1.2 Manuel d'utilisateur Page 223

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