ARM ARM1176JZF-S Manual do Utilizador descarregar pdf (Página 3)

Confidential

555

Data Sizes and Instruction Sets

When used in relation to the ARM:

Halfword means 16 bits (two bytes)

Word means 32 bits (four bytes)

Doubleword means 64 bits (eight bytes)

Most ARMs implement two instruction sets

32-bit ARM Instruction Set

16-bit Thumb Instruction Set

Latest ARM cores introduce a new instruction set Thumb-2

Provides a mixture of 32-bit and 16-bit instructions

Maintains code density with increased flexibility

Jazelle-DBX cores can also execute Java bytecode

666

The ARM has seven basic operating modes:

Each mode has access to own stack and a different subset of registers

Some operations can only be carried out in a privileged mode

Processor Modes

Entered when a high priority (fast) interrupt is

raised

FIQ

Entered when a low priority (normal) interrupt

is raised

IRQ

Used to handle memory access violationsAbort

Used to handle undefined instructionsUndef

Privileged mode using the same registers as

User mode

System

Unprivileged

mode

Mode under which most Applications / OS

tasks run

User

Privileged

modes

Entered on reset and when a Software Interrupt

instruction (SWI) is executed

Supervisor

(SVC)

DescriptionMode

Exception modes

1 2 3 4 5 6 7 8 ... 18 19

Comentários a estes Manuais

Sem comentários

ARM ARM1176JZF-S Manual do Utilizador Página 3

Comentários a estes Manuais

Manuais e produtos relacionados com Processadores ARM ARM1176JZF-S