ARM ARM7TDMI User Manual download pdf (Page 42)

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5.7 NOP – No Operation

Syntax:

NOP

Description:

There are numerous ways to encode a NOP (no operation) instruction for the

ARM7TDMI processor, such as adding 0 to a register, ORing a register with 0,

branching to the next instruction, etc. The actual encoding of the NOP is assembler-

dependent.

5.8 POP - Pop

Syntax:

POP{cond} reg_list

Description:

POP is a pseudonym for the LDMIA instruction, with R13! specified for the base register

(Rn). The PUSH/POP instructions assume a full-descending (FD) stack organization.

5.9 PUSH - Push

Syntax:

PUSH{cond} reg_list

Description:

PUSH is a pseudonym for the STMDB instruction, with R13! specified for the base

organization.

5.10 ROR – Rotate Right

Syntax:

ROR{cond}{S} <Rd>, <Rm>, <Rs>

ROR{cond}{S} <Rd>, <Rm>, <#shift_count>

Description:

ROR is a synonym for the MOV instruction with an ROR shifter operand. If an

immediate shift count is used, it is limited to the range 1-31. If Rm is not included, the

assembler will assume it is the same as Rd.

ROR R0, R1 is equivalent to MOV R0, R0, ROR R1

ROR R0, R1, R2 is equivalent to MOV R0, R1, ROR R2

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ARM ARM7TDMI User Manual Page 42