Arm VERSION 1.2 Instrukcja Użytkownika Pobierz pdf (Strona 150)

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ARM Instruction Reference

4.4.1 MUL and MLA

Multiply and multiply-accumulate (32-bit by 32-bit, bottom 32-bit result).

Syntax

MUL{cond}{S} Rd, Rm, Rs

MLA{cond}{S} Rd, Rm, Rs, Rn

where:

cond

is an optional condition code (see Conditional execution on page 4-4).

is an optional suffix. If

is specified, the condition code flags are updated

on the result of the operation (see Conditional execution on page 4-4).

is the ARM register for the result.

Rm, Rs, Rn

are ARM registers holding the operands.

r15 cannot be used for any of

, or

cannot be the same as

Usage

The

MUL

instruction multiplies the values from

and

, and places the least significant

32 bits of the result in

The

MLA

instruction multiplies the values from

and

, adds the value from

, and

places the least significant 32 bits of the result in

Condition flags

is specified, these instructions:

• update the N and Z flags according to the result

• do not affect the V flag

• corrupt the C flag in ARM architecture v4 and earlier

• do not affect the C flag in ARM architecture v5 and later.

Architectures

These instructions are available in ARM architecture v2 and above.

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