ARM学习笔记

ARMv7与ARMv8的简要对比：

CPU	Core Version	Pipeline	DMIPS/MHz	Physical Memory Addresses
Cortex A7	ARMv7	In-Order	1.9	LPAE 40bits
Cortex A15	ARMv7	Out-of-Order	3.5	LPAE 40bits
Cortex A53	ARMv8	In-Order	2.3	40bits
Cortex A57	ARMv8	Out-of-Order	4.1	44bits

 

AArch64寄存器组：

Register	Special	Role in the procedure call standard
x0…x7		Parameter/result registers.
x8		Indirect result location register.
x9…x15		Temporary registers.
x16	IP0	The first intra-procedure-call scratch register (can be used by call veneers and PLT code); at other times may be used as a temporary register.
x17	IP1	The second intra-procedure-call temporary register (can be used by call veneers and PLT code); at other times may be used as a temporary register.
x18		The Platform Register, if needed; otherwise a temporary register.
x19…x28		Callee-saved registers.
x29	FP	The Frame Pointer.
x30	LR	The Link Register.
SP		The Stack Pointer.

 

AArch32寄存器组：

Register	Special	Role in the procedure call standard
r0…r3		Parameter/result registers.
r4…r8 r9(also as platform register) r10,r11		Temporary registers.
r12	IP	The Intra-Procedure-call scratch register.
r13	SP	The second intra-procedure-call temporary register (can be used by call veneers and PLT code); at other times may be used as a temporary register.
r14	LR	The Platform Register, if needed; otherwise a temporary register.
r15	PC	Callee-saved registers.

 

ARMv8支持的数据类型：

Data Type	Length
Data Type	Length
Byte (B)	8 bits.
Halfword (H)	16 bits.
Word (S)	32 bits.
Doubleword (D)	64 bits.
Quadword (V)	128 bits.

 

ARMv8通用寄存器可区分32bits（Wn）和64bits（Xn）：

63                                            32 31                                               0

                                               Rn                                                 

                                                    |-------------------Wn-------------------|

|---------------------------------------Xn-----------------------------------------|

 

SIMD与浮点数相关的寄存器有8bits～128bits不同的size：

127                                                                                                64  63                                          32  31                 16 15       8 7      0

                                                                                                      Vn                                                                                                 

                                                                                                                                                                                                        |-Bn-|

                                                                                                                                                                                          |-------Hn------|

                                                                                                                                                               |------------------Sn-----------------|

                                                                                                            |----------------------------------------Dn------------------------------------|

|------------------------------------------------------------------------------------Qn------------------------------------------------------------------------------|