Motorola MCF5281 用户手册

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Chapter 2.  ColdFire Core  

2-9

The original ColdFire instruction set architecture (ISA) was derived from the
M68000-family opcodes based on extensive analysis of embedded application code. After
the initial ColdFire compilers were created, developers identified ISA additions that would
enhance both code density and overall performance. Additionally, as users implemented
ColdFire-based designs into a wide range of embedded systems, they identified frequently
used instruction sequences that could be improved by the creation of new instructions. This
observation was especially prevalent in development environments that made use of
substantial amounts of assembly language code.

Table 2-4 summarizes the new instructions added to Revision A+ ISA. For more details see
Section 2.14, “ColdFire Instruction Set Architecture Enhancements.”

D0-D7

0x(0,1)80-0x(0,1)87 No

Data registers 0-7 (0 = load, 1 = store)

A0-A7

0x(0,1)88-0x(0,1)8F No

Address registers 0-7 (0 = load, 1 = store)
A7 is user stack pointer

OTHER_A7

0x800

No

Other stack pointer

VBR

0x801

Yes

Vector base register

MACSR

0x804

No

MAC status register

MASK

0x805

No

MAC address mask register

ACC0-ACC3

0x806, 0x809, 
0x80A, 0x80B

No

MAC accumulators 0-3

ACCext01

0x807

No

MAC accumulator 0, 1 extension bytes

ACCext23

0x808

No

MAC accumulator 2, 3 extension bytes

SR

0x80E

No

Status register

PC

0x80F

Yes

Program counter

FLASHBAR

0xC04

Yes

Flash base address register 

RAMBAR

0xC05

Yes

SRAM base address register