MC68020 查看數據表（PDF） - Freescale Semiconductor

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MC68020

MICROPROCESSORS USER’S MANUAL

Freescale Semiconductor 

Freescale Semiconductor, Inc.

1.3 DATA TYPES AND ADDRESSING MODES OVERVIEW

For detailed information on the data types and addressing modes supported by the

MC68020/EC020, refer to M68000PM/AD, M68000 Family Programmer’s Reference

Manual.

The MC68020/EC020 supports seven basic data types:

1. Bits

2. Bit Fields (Fields of consecutive bits, 1–32 bits long)

3. BCD Digits (Packed: 2 digits/byte, Unpacked: 1 digit/byte)

4. Byte Integers (8 bits)

5. Word Integers (16 bits)

6. Long-Word Integers (32 bits)

7. Quad-Word Integers (64 bits)

In addition, the MC68020/EC020 instruction set supports operations on other data types

such as memory addresses. The coprocessor mechanism allows direct support of floating-

point operations with the MC68881 and MC68882 floating-point coprocessors as well as

specialized user-defined data types and functions.

The 18 addressing modes listed in Table 1-1 include nine basic types:

1. Register Direct

2. Register Indirect

3. Register Indirect with Index

4. Memory Indirect

5. PC Indirect with Displacement

6. PC Indirect with Index

7. PC Memory Indirect

8. Absolute

9. Immediate

The register indirect addressing modes have postincrement, predecrement, displacement,

and index capabilities. The PC modes have index and offset capabilities. Both modes are

extended to provide indirect reference through memory. In addition to these addressing

modes, many instructions implicitly specify the use of the CCR, stack pointer, and/or PC.

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M68020 USER’S MANUAL

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